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Phone power bank

phone power bank

Power Banks are portable battery devices that can be charged through a wall outlet and be used later to charge mobile devices. You should also know how a. Portable chargers or power banks containing a lithium ion battery must be packed in carry-on bags. For more information, see the FAA guidance on portable. Weatherproof, dustproof and shockproof, the 10,000mAh Power Bank is the ideal via E-mail from Bullitt Mobile Ltd (Manufacturer of Cat® phones).

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Mobile phone battery power bank

Running out of battery can be a big problem, especially when you might not have access to a wall outlet to charge your phone. Cue power banks! A power bank can keep your phone full of battery without an outlet, so you’ll never have to miss a selfie opportunity or a call from your mom.

It’s time to get charged up to learn all about power banks, from their purpose, the different types, and why you need one!

What is the Purpose of a Power Bank?

What is the Purpose of a Power Bank?

The purpose of a power bank is to recharge battery-powered electronics when you’re on-the-go! A power bank can be small enough to fit in your pocket or they can be larger with a higher capacity.

Power banks are used to charge cell phones, tablets, speakers, and even laptops! If you can plug it in a wall to charge, chances are a power bank can charge it.

What is the Purpose of a Power Bank?
When Was the First Power Bank Made?

When Was the First Power Bank Made?

The first portable power bank was created in 2001 by a Chinese company called Pisen. The original design was two AA batteries pieced together by a circuit! It made its public debut at the Las Vegas International Consumer Electronics Show.

The first power bank was bulky and had a short battery life. Today, there are much more sophisticated and compact designs with far superior battery life. Most modern power banks can fit in the palm of your hand and charge your smartphone several times before running out of battery.

When Was the First Power Bank Made?

What Are the Different Types of Power Banks?

Power banks come in a variety of different shapes and sizes. Some power banks have multiple uses in addition to charging your electronic devices!

The different types of power banks include:

  • Block power bank
  • Credit card power bank
  • Keychain power bank
  • Wireless power bank
  • Flashlight power bank
  • Speaker power bank
  • Novelty power bank
  • Bluetooth earbud power bank
  • Lantern power bank
  • Solar power bank
  • High capacity power bank
Block Power Bank

Block Power Bank

Block power banks are one of the most common types of portable chargers. The blocks can capital one bank usa contact number in the shape of a slim rectangle, a log, or a wider rectangle. This type of power bank is great for keeping in your bag or backpack for those moments when you need some extra juice on-the-go.

Credit Card Power Bank

Credit Card Power Bank

A credit card power bank is a portable charger with a slim rectangular design, hence its name. This kind of power bank fits comfortably inside your pocket without feeling bulky. The discreet design allows you to slip it inside small places like a wallet or padfolio without taking up a ton of room.

Keychain Power Bank

Keychain Power Bank

You never know when you might find yourself with a phone on low battery and no wall outlet. A keychain power bank is compact enough to add to your keyring and take with you everywhere! The next time you need a quick charge, you’ll have your power bank easily accessible.

Wireless Power Bank

Wireless Power Bank

Keeping track of cords can become a nuisance. A wireless power bank works by simply resting the back of your phone on top, and letting your battery charge. Before you get a wireless power bank, be sure your device is compatible with this type of charger.

Flashlight Power Bank

Flashlight Power Bank

If you go camping, fishing, or hiking, a flashlight power bank is a necessity. Not only does the flashlight provide safety at night, but it can also charge your phone. It’s also a good idea to keep a flashlight power bank in your home in case of a power outage.

Speaker Power Bank

Speaker Power Bank

Next time you head to the beach or to a picnic, don’t forget to grab a speaker power bank. Keep your phone charged while listening to your favorite playlist with this compact power bank. It’s also handy for bike rides or while working on an outdoor project.

Novelty Power Bank

Novelty Power Bank

There are some power banks that don’t look like a power bank at all, like this Rubik’s Cube! The best part is you can twist the colored blocks while your phone charges. It’s still compact and fits in the palm of your hand, so you don’t have to worry about running out of space in your bag.

Bluetooth Earbud Power Bank

Bluetooth Earbud Power Bank

This power bank not only works as a portable charger for your phone, but it’s also a port to store and charge wireless Bluetooth headphones! One end of the power bank has the connection to charge your device, and the other has two slots for the earbuds.

Lantern Power Bank

Lantern Power Bank

Anyone who is outdoorsy will want a lantern power bank. Use the light when you need it, and then charge your phone at the same time. With this power bank, you can use a charging cable, or you can place your phone on top to wirelessly charge it.

Solar Power Bank

Solar Power Bank

Go green with a solar power bank! Leave your power bank in the sun to charge it up, and then connect it to your phone. A solar power bank is great to use over an extended period because you don’t have to worry about needing a wall outlet to recharge it.

High Capacity Power

High Capacity Power Bank

High capacity power banks provide a lot of power and have a battery with 20,000 mAh or higher. These power banks can charge multiple devices at once, or one device multiple times before needing to be charged.

There is truly a different type of power bank to satisfy every need. Whether you end up having one favorite or multiple models for different occasions, a power bank is always a good item to keep on hand.

What Does mAh Mean?

What Does mAh Mean?

mAh means milliamp hour. It is a unit of measurement used for electric power, specifically for batteries. A battery that has a higher mAh will have more power and battery life.

For rechargeable batteries found in power banks, the mAh shows how much charge the battery can hold, and how long it can power another electronic before needing to be charged.

What Does mAh Mean?

How Do I Know My Power Bank Capacity?

Before you invest in a power bank, you’ll want to know how long the battery will last. Knowing the capacity of your power bank will help you make sure you get one that will meet your needs. Use the equation below to find the approximate battery life of your power bank.

How Do I Know My Power Bank Capacity?

If your power bank has 10,000 mAh, you would divide that by the mAh of the device you want to charge. A quick online search can tell you the mAh of your device if you aren’t sure or can’t find the battery. For example, an iPhone XS uses a 2,658 mAh battery. Using the equation, it would take 3 hours and 7 minutes of charging your iPhone XS before your 10,000 mAh power bank ran out of battery life.

Which Type of Power Bank is Best?

Which Type of Power Bank is Best?

The best type of power bank will have a mAh that is higher than the device you want to charge. The larger the battery is on your phone or other electronic device, the more power you’ll need from your power bank to charge it.

For example, if your electronic device has a battery with 2,000 mAh, you’ll want to get a power bank that has at least 2,000 mAh or more. That way, you’ll be able to get at least one full charge for your device without having to recharge the power bank.

Which Type of Power Bank is Best?

What Is the Difference Between a Power Bank and a Portable Charger?

There is no difference between a power bank and a portable charger. Both names can be used to refer to the exact same battery pack you use to charge a device.

What Is the Difference Between a Power Bank and a Portable Charger?

A power bank has several nicknames including:

  • Battery pack
  • Fuel bank
  • Pocket power cell
  • Back-up charging device
  • Wireless charger
  • Portable charger
What Is the Difference Between a Power Bank and a Portable Charger?

Regardless of the name you want to use for your power bank, you’ll be thankful you have it handy when your electronic device needs some extra juice!

What Power Banks Are Allowed on Planes?

What Power Banks Are Allowed on Planes?

According to the Transportation Security Administration, power banks containing a lithium ion battery must be packed in a carry-on bag. The reason why power banks are not allowed in checked bags is because the battery contains potentially hazardous flammable materials.

The Federal Aviation Administration (FAA) does not allow any type of battery onboard an aircraft that exceeds 27,000 mAh. Keep these guidelines in mind before flying and be sure to properly pack your power banks!

What Power Banks Are Allowed on Planes?

What Are the Advantages of Power Banks?

Now that you know what a power bank is, you might be wondering if a power bank is worth it. There are several advantages to having a power bank you should consider before getting your own.

The advantages of power banks include:

Easily Portable

Easily Portable

Most power banks can fit in the palm of your hand, making them easy to take with you anywhere! You won’t have to worry about it taking up too much space in your bag or pocket.



Power banks come in a variety of colors and styles you can choose from. You can also add different designs to your power banks to make it your own.



You don’t have to spend an arm and a leg to get a quality power bank. Most power banks are under $20 and will keep your phone charged whenever you need it.



Each time you need to charge your electronic devices, you don’t have to get a new power bank. You can recharge and reuse the same power bank over and over.



We don’t always have time to wait for our phone battery to charge. Thankfully, you can take a power bank with you to quickly charge your phone on-the-go.

Reduces Worry of a Dead Cell Phone

Reduces Worry of a Dead Cell Phone

No matter where you are, you won’t have to worry about your phone running out of battery as long as you have a power bank handy.

Power banks are an accessory worth having! If you have smartphone or other electronics that you need to keep charged, then you’ll want to have a power bank with you.

The Bottom Line

A power bank can make a huge difference while camping, traveling, or attending a festival. It can help prevent your phone, tablet, or other electronic device from running out of battery. You never know when you might be stuck without a wall outlet, so keeping a power bank nearby can save you in the long run.


Electronics Notes. (2020). What is a power bank – portable charger. Retrieved on March 3, 2020, from

Uber Gizmo. (2020). What is mAh? Retrieved on March 3, 2020, from

Esposito, Felipe. (2019, September 17). iPhone 11 and iPhone 11 Pro have up to 3,969 mAh battery capacity and 4GB of RAM. Retrieved on March 3, 2020, from

Bryan. (2020, February 4). What Does mAh Stand For in Batteries? Retrieved on March 3, 2020, from

TSA. (2020). Power Banks. Retrieved on March 3, 2020, from

SWICAD. (2018, September 17). History of the Power Bank. Retrieved on March 4, 2020, from

Brease, Tom. (2017, November 13). Pisen: From power bank invention to power bank innovation. Retrieved on March 4, 2020, from

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Gianna Petan

About the author

Gianna Petan

Meet Gianna - no stranger to all things promo products. Her background in research-based writing, linguistics, and advertising gives her an edge in blogging about the marketing industry. More articles by Gianna Petan


Introduction: PowerBanks "How It Works"

Powerbanks are becoming popular these days as our gadgets or devices were all getting smarter & versatile tools in our daily lives specially for various types of communications such as calls,sms,emails and other task,and these smart devices (smartphones & tablets) needs more power for them to work and last for a day as they should be. Normally the devices that needs a back up power are the smartphones & tablets these days.And most of us individually owns one.But not all people knew how powerbank works literally.And some sellers just don't explain on how their Powerbank works.And many people just end up buying the wrong specifications of powerbank that suits phone power bank need of their devices (such as smartphones & tablets).That's the reason I made this and compiled some facts gathered from different manufacturers and blogs site ,and made it into one instructables that may help some DIY'ers who planned to build their own powerbank or just buy the right one.

Step 1: How It Works? What Type of Powerbank to Choose?

Power Banks are all the rage, they came in various shapes and sizes.,but what are they for? We explore their potential, and how to choose the right one.
What is a Power Bank and what can they charge?
Portable Power Banks are comprised of a special battery in a special case with a special circuit to control power flow. They allow you to store electrical energy (deposit it in the bank) and then later use it to charge up a mobile device (withdraw it from the bank). Power Banks have become increasingly popular as the battery life of our beloved phones, tablets and portable media players is outstripped by the amount of time we spend using them each day. By keeping a battery backup close by, you can top-up your device(s) while far from a wall outlet.
The Power Banks we're talking about are good for almost any USB-charged devices. Cameras, GoPros, Portable speakers, GPS systems, MP3 players, smartphones and even some tablets can be charged from a Power Bank - practically anything that charges from USB at home can be charged from a Power Bank - you just have to remember to keep your Power Bank charged, too!
Power Banks may also be known as Power Stations or Battery Banks, too.
•What types of Power Banks are there?
-Three major types of Power Bank found on the market today:
1. Universal Power Bank. They come in many sizes and configurations which can phone power bank tailored to your device requirements and to your budget.
2. Solar-Charged Power Bank. They have photovoltaic panels which can trickle-charge the internal battery when placed in sunlight. Solar charging isn't fast, so they can usually charge via cable as well.
3. The third type of Power Bank is the older-style battery phone case. While they can be handy, this type of Power Bank has very narrow device compatibility,
•How do I charge a Power Bank?
Most commonly, a Power Bank will have a dedicated input socket for receiving power. This power can come from a USB socket on your computer, but may charge faster when using a wall socket adapter. We most often see Power Banks use a Mini or Micro-USB socket for charging, and full-sized USB sockets for discharging. On very rare occasions, Power Banks can use the same socket for input and output, but this is rare and should not be assumed of any Power Bank, as trying to force power into an output can damage the battery. Always check the manual for specific instructions if you're not able to find a clearly marked input socket.
Depending on the capacity of the Power Bank and its current charge level, it can take quite a while to fill up. For example, a 1500mAh rated Power Bank should take about the same time as your typical smartphone to charge. For larger banks, this time can be doubled, tripled or quadrupled. Most Power Banks have both an LED indicator to show when they are at capacity, and a safety cut-off to prevent overcharging and overheating. Whenever possible, remove the Power Bank from charge when it is full, or at least avoid leaving it connected long-term after its full. Ambient temperature and power flow will also affect charge times, so it's best to keep it topped off regularly.
Some Power Banks don't work well with high-capacity chargers (like the ones that come with iPads). Trying to fast-charge a Power Bank from a 2A charger can result in damage to the internal circuitry.
•How long does a Power Bank last?
This is a bit of a loaded question. There are two important life expectancies to consider:
1. The number of charge/discharge cycles a Power Bank can reliably perform in its lifetime.
2. How long a Power Bank can retain its charge when not in use.
The answer to point one can differ between models of Power Bank, their internal components and the quality of their manufacturing. We try not to stock Power Banks which have fewer than 500 charge cycles in them. This would allow you to charge a device from the Power Bank every day for a 1.5 years before it started to lose its ability to hold charge long-term. Better and more expensive Power Banks can last longer, while smaller and cheaper units may fall short phone power bank on their treatment. Power Banks are generally not used daily, so they often last much longer than 18 months in real-world usage patterns.
Point two depends on the quality of the controller circuitry and battery cells. A good Power Bank can hold charge for 3 to 6 months with minimal loss. Lower quality Power Banks may struggle to retain a useful charge more than 4 to 6 weeks. In this regard, you get what you pay for, and if you need a long-term emergency power supply consider increasing your budget to ensure you're not going to be caught short. Most Power Banks will slowly lose charge over time, to a degree influenced by the environment and their treatment. For example, leaving a Power Bank in the car where the temperature can fluctuate greatly over time can shorten its lifespan.
•Technical Term Glossary
What does mAh mean?
Batteries common to mobile devices and Power Banks are rated on their ampere-hours, measured in milliamps to create non-decimal numbers. The mAh ratings denote capacity for power flow over time.
Li-Ion & Li-Polymer
Lithium-Ion and Lithium-Polymer batteries are the most common rechargeable cell types found in Power Banks. Lithium-Ion cells are generally cheaper and limited in mAh capacity, while Lithium-Polymer cells can be larger and don't suffer from a memory effect over time.
When power is transferred, there is always loss due to resistance. Power Banks are not able to transfer 100% of their actual capacity to a device, so we factor in this loss when calculating how many times an average device can be charged from a fully powered Power Bank of any given size. Efficiency ratings differ between Power Banks based on their cell type, component quality and environment. Ratings between 80% and 90% are the current industry standard. Beware of suspiciously low-cost options claiming efficiency ratings of over 90%.
Device Depletion
This is the state of the battery in the device you wish to charge. The lower its power, the more a Power Bank has to work to bring it back to life. We consider charging from 20% to 90% a full charge, as the efficiency loss increases beyond these points, leading to wasted charging potential. Going from 5% to 100% can take exponentially more power.

Step 2: Choosing the Right Powerbanks:

1.How do I know which
powerbank suits my device?
Depending on individual
needs and requirements,
there are several general
criteria to consider when
selecting a powerbank:
a) Capacity
For example if your phone battery is 1500mAh and is 0% now, a powerbank with 2200mAh can charge your phone 1 time. If your phone battery is 3000mAh and is 0% now, a powerbank with 2200mAh will not be able to charge your phone to full because the phone battery capacity is higher than the powerbank. If you require a powerbank that is able to charge your phone several times, you need a powerbank with higher capacity.
b) Number of output
1 output to charge 1 device, 2 outputs to charge 2 devices.
c) Output specification
1A-1.5A output is generally for smartphones, 1.5A-2.0A output is generally for tablets.
2. How long do I need to charge the powerbank for the first time and subsequent time?/ How many times can a powerbank charge my phone?
a) Powerbank is already pre-charged and ready to use.
b) Re-charging time depends on the capacity of the powerbank, remaining power in the powerbank and the power supply.
-Powerbank: 13000mAh (0% remaining)
-Power Supply/ Input: 1000mA plug
-Calculation: 13000mAh/ 800mA = minimum 16.25 hours
(Why 800mA? An estimate of 20% power is consumed during the charging/ discharging process)
c) Similar formula applies to calculate number of times a powerbank can charge a phone.
-Powerbank: 10000mAh (full at 90%)
-Phone Battery: 1500mAh
-Calculation: (10000mAh x 90% x 80%) / 1500mAh = up to 5 times
(Why 90%? Assuming the power bank is well maintained in good working condition and can conserve up to 90% power)
(Why 80%? An estimate of 20% power is consumed during the charging/ discharging process)
* Note that the calculation is based on normal condition whereby the powerbank or device (phone/ tablet) is not in use during charging process. A running device generally consumes power therefore if your device is actively in use during the charging process, the charging performance may not meet the expectation.
* The above calculations are examples made simple for easy reference. Accuracy may vary.

•Images in order
1.Commercial PB (upgraded from 1200 to 2800 mah)
2.Commercial PB Kit(modified by adding switch and upgraded 2400 to 4000mah)
3.Commercial PB under my testing.

Step 3: Homebrewed Powerbanks

Image1-using 8 AA Nimh 2800 mah batteries
Image2-using 3*18650 2200mah Li-ion batteries

*ibles can be found on my DIYs

Step 4: Difference Between Li-ion and Li-Po

Lithium-ion batteries use a variety of cathodes and electrolytes. Common combinations use an anode of lithium (Li) ions dissolved in carbon or graphite and a cathode of lithium cobalt-oxide (LiCoO2) or lithium manganese-oxide (LiMn2O4) in an liquid electrolyte of lithium salt. Because they use a liquid electrolyte, lithium-ion batteries are limited in shape to either prismatic (rectangular) or cylindrical. The cylindrical form has a similar construction to other cylindrical rechargeable batteries,Prismatic batteries have the anode and cathode inserted into the rectangular enclosure. The image link at illustrates this construction method. Lithium-Ion-Polymer batteries are the next stage in development and replace the liquid electrolyte with a plastic (or polymer) electrolyte. This allows the batteries to be made in a variety of shapes and sizes.
The significant advantages of lithium-ion batteries are size, weight and energy density (the amount of power the battery can provide). Lithium-ion batteries are smaller, lighter and provide more energy than either nickel-cadmium or nickel-metal-hydride batteries. Additionally, lithium-ion batteries operate in a wider temperature range and can be recharged before they are fully discharged without creating a memory problem.
As with most new technology, the disadvantage is pricing. Currently, lithium-ion and lithium-ion-polymer batteries are more expensive to manufacture than standard rechargeable batteries. Part of this expense is due to the volatile nature of lithium.
Lithium-ion batteries are most commonly used in applications where one or more of the advantages (size, weight or energy) outweigh the additional cost, such as mobile telephones and mobile computing devices. Lithium-ion-polymer batteries are used when the battery needs to be a particular shape.
Lithium-Ion Battery Characteristics
Type Secondary
•Chemical Reaction Varies, depending on electrolyte.
Operating Temperature 4∫ F to 140∫ F ( -20∫ C to 60∫ C)
•Recommended for Cellular telephones, mobile computing devices.
•Initial Voltage 3.6 & 7.2
Capacity Varies (generally up to twice the capacity of a Ni-Cd cellular battery)
•Discharge Rate Flat
•Recharge Life 300 - 400 cycles
•Charging Temperature 32∫ F to 140∫ F (0∫ C to 60∫ C)
•Storage Life Loses less than 0.1% per month.
•Storage Temperature -4∫ F to 140∫ F ( -20∫ C to 60∫ C)
ï The chemical construction of this battery limits it to a rectangular shape.
ï Lighter than nickel-based secondary batteries with (Ni-Cd and NiMH).
Lithium-Ion-Polymer Battery Characteristics
Type Secondary
Chemical Reaction Varies, depending on electrolyte.
Operating Temperature Improved performance at low and high temperatures.
Recommended for Cellular telephones, mobile computing devices.
•Initial Voltage 3.6 & 7.2
•Capacity Varies depending on the battery; superior to standard lithium-ion.
•Discharge Rate Flat
•Recharge Life 300 - 400 cycles
•Charging Temperature 32∫ F to 140∫ F (0∫ C to 60∫ C)
•Storage Life Loses less than 0.1% per month.
•Storage Temperature -4∫ F to 140∫ F ( -20∫ C to 60∫ C)
ï Lighter than nickel-based secondary batteries with (Ni-Cd and NiMH).
ï Can be made in a variety of shapes.

Step 5: Facts About Lithium Ion:

Is Lithium-ion the Ideal Battery?For many years, nickel-cadmium had been the only suitable battery for portable equipment from wireless communications to mobile computing. Nickel-metal-hydride and lithium-ion emerged In the early 1990s, fighting nose-to-nose to gain customer's acceptance. Today, lithium-ion is the fastest growing and most promising battery chemistry.
The lithium-ion battery
Pioneer work with the lithium battery began in 1912 under G.N. Lewis but it was not until the early 1970s when the first non-rechargeable lithium batteries became commercially available. lithium is the lightest of all metals, has the greatest electrochemical potential and provides the largest energy density for weight.
Attempts to develop rechargeable lithium batteries failed due to safety problems. Because of the inherent instability of lithium metal, especially during charging, research shifted to a non-metallic lithium battery using lithium ions. Although slightly lower in energy density than lithium metal, lithium-ion is safe, provided certain precautions are met when charging and discharging. In 1991, the Sony Corporation commercialized the first lithium-ion battery. Other manufacturers followed suit.
The energy density of lithium-ion is typically twice that of the standard nickel-cadmium. There is potential for higher energy densities. The load characteristics are reasonably good and behave similarly to nickel-cadmium in terms of discharge. The high cell voltage of 3.6 volts allows battery pack designs with only one cell. Most of today's mobile phones run on a single cell. A nickel-based pack would require three 1.2-volt cells connected in series.
Lithium-ion is a low maintenance battery, an advantage that most other chemistries cannot claim. There is no memory and no scheduled cycling is required to prolong the battery's life. In addition, the self-discharge is less than half compared to nickel-cadmium, making lithium-ion well suited for modern fuel gauge applications. lithium-ion cells cause little harm when disposed.
Despite its overall advantages, lithium-ion has its drawbacks. It is fragile and requires a protection circuit to maintain safe operation. Built into each pack, the protection circuit limits the peak voltage of each cell during charge and prevents the cell voltage from dropping too low on discharge. In addition, the cell temperature is monitored to prevent temperature extremes. The maximum charge and discharge current on most packs are is limited to between 1C and 2C. With these precautions in place, the possibility of metallic lithium plating occurring due to overcharge is virtually eliminated.
Aging is a concern with most lithium-ion batteries and many manufacturers remain silent about this issue. Some capacity deterioration is noticeable after one year, whether the battery is in use or not. The battery frequently fails after two or three years. It should be noted that other chemistries also have age-related degenerative effects. This is especially true for nickel-metal-hydride if exposed to high ambient temperatures. At the same time, lithium-ion packs are known to have served for five years in some applications.
Manufacturers are constantly improving lithium-ion. New and enhanced chemical combinations are introduced every six months or so. With such rapid progress, it is difficult to assess how well the revised battery will age.
Storage in a cool place slows the aging process of lithium-ion (and other chemistries). Manufacturers recommend storage temperatures of 15∞C (59∞F). In addition, the battery should be partially charged during storage. The manufacturer recommends a 40% charge.
The most economical lithium-ion battery in terms of cost-to-energy ratio is the cylindrical 18650 (size is 18mm x 65.2mm). This cell is used for mobile computing and other applications that do not demand ultra-thin geometry. If a slim pack is required, the prismatic lithium-ion cell is the best choice. These cells come at a higher cost in terms of stored energy.
ï High energy density - potential for yet higher capacities.
ï Does not need prolonged priming when new. One regular charge is all that's needed.
ï Relatively low self-discharge - self-discharge is less than half that of nickel-based batteries.
ï Low Maintenance - no periodic discharge is needed; there is no memory.
ï Specialty cells can provide very high current to applications such as power tools.
ï Requires protection circuit to maintain voltage and current within safe limits.
ï Subject to aging, even if not in use - storage in a cool place at 40% charge reduces the aging effect.
ï Transportation restrictions - shipment of larger quantities may be subject to regulatory control. This restriction does not apply to personal carry-on batteries.
ï Expensive to manufacture - about 40 percent higher in cost than nickel-cadmium.
ï Not fully mature - metals and chemicals are changing on a continuing basis.
The lithium polymer battery
The lithium-polymer differentiates itself from conventional battery systems in the type of electrolyte used. The original design, dating back to the 1970s, uses a dry solid polymer electrolyte. This electrolyte resembles a plastic-like film that does not conduct electricity but allows ions exchange (electrically charged atoms or groups of atoms). The polymer electrolyte replaces the traditional porous separator, which is soaked with electrolyte.
The dry polymer design offers simplifications with respect to fabrication, ruggedness, safety and thin-profile geometry. With a cell thickness measuring as little as one millimeter (0.039 inches), equipment designers are left to their own imagination in terms of form, shape and size.
Unfortunately, the dry lithium-polymer suffers from poor conductivity. The internal resistance is too high and cannot deliver the current bursts needed to power modern communication devices and spin up the hard drives of mobile computing equipment. Heating the cell to 60∞C (140∞F) and higher increases the conductivity, a requirement that is unsuitable for portable applications.
To compromise, some gelled electrolyte has been added. The commercial cells use a separator/ electrolyte membrane prepared from the same traditional porous polyethylene or polypropylene separator filled with a polymer, which gels upon filling with the liquid electrolyte. Thus the commercial lithium-ion polymer cells are very similar in chemistry and materials to their liquid electrolyte counter parts.
Lithium-ion-polymer has not caught on as quickly as some analysts had expected. Its superiority to other systems and low manufacturing costs has not been realized. No improvements in capacity gains are achieved - in fact, the capacity is slightly less than that of the standard lithium-ion battery. Lithium-ion-polymer finds its market niche in wafer-thin geometries, such as batteries for credit cards and other such applications.
ï Very low profile - batteries resembling the profile of a credit card are feasible.
ï Flexible form factor - manufacturers are not bound by standard cell formats. With high volume, any reasonable size can be produced economically.
ï Lightweight - gelled electrolytes enable simplified packaging by eliminating the metal shell.
ï Improved safety - more resistant to overcharge; less chance for electrolyte leakage.
ï Lower energy density and decreased cycle count compared to lithium-ion.
ï Expensive to manufacture.
ï No standard sizes. Most cells are produced for high volume consumer markets.
ï Higher cost-to-energy ratio than lithium-ion

Step 6: Powerbank Accesories

•image 1 - bundled with commercial Powerbanks.
•image 2- additional(option only) accesory to extend compatibility to any devices.

Step 7: Functions of Powerbanks

•image 1- PB on portable speaker great for outdoor use.
•image2- PB on LG Prada using usb cable adapters
•image 3 - PB on portable DVD R/W optical drive
•image 4 - pendrive powerbank (single AA Nimh 2800 mah )

Step 8: Common Problems/Troubleshooting

1.Powerbank unable to charge my tablet?
a) Powerbank with 2A output to charge tablets. While some tablets can accept lower input (1A or 1.5A), the charging is slower and sometimes can only be charged when the tablet is in sleep mode.
b) Some tablet is cables might not be compatible with power bank due to different cable chipset design. For Samsung Galaxy Tab in particular, we recommend using the cable and connector meant for power bank (comes with some power banks.
2.Powerbank battery drained off very fast?
a) Generally, a well maintained powerbank can retain up to 80-90% of its original capacity. Please check your device (phone/ tablet) original battery capacity and the powerbank capacity. Please also see answer 1.a. above.
b) The number of times a powerbank can charge your device very much depends on the capacity of both the powerbank and the device. Examples of calculation shown in answer 2 above.
c) Please do not attach cables to the powerbank when not in use.
3.Unable to turn on my powerbank?
a) It is possible that your powerbank is fully drained. Please charge your powerbank. The indicator will start blinking when the powerbank receives sufficient power.
b) It is possible that your powerbank went into sleep mode. The powerbank will automatically cut-off the power and go into sleep mode when it detects possibility of over-charge/ over-discharge/ short-circuit. This is sometimes due to faulty cable issue. Please activate the ìsleepingî powerbank by charging it with its wall plug (3-pin plug) and use a good condition cable.
4.What is the lifespan of the powerbank?
Generally, a properly maintained powerbank can retain up to 80-90% of its original capacity at 400-500 charge and discharge cycle (charge then discharge = 1 cycle, regardless of whether you charge/ discharge it partially or fully). Until your power bank no longer holds sufficient charge to meet your needs, you may choose to purchase a new one.

Step 9:

Step 10: Credits to the Following Sources

And there it is,Powerbank a very useful devices that really help in time of needs.,particular when you are on outdoor or during calamities when powergrid are down.,
Hoping you like it & hopefully helped those who are interested in doing or building their own powerbanks.

•some of the DIY Powerbank shown here are available on my Instructables found here.

4 People Made This Project! phone power bank

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Battery charger

Device used to provide electricity

For other senses of this term, see AC adapter.

This unit charges batteries until they reach a specific voltage, then trickle chargesthem until disconnected.
A simple charger for NiCD batteries that outputs 300mA of 12V DC.

A battery charger, or recharger,[1][2] is a device that stores energy in a battery by dmv almaden san jose an electric current through it.

The charging protocol (how much voltage or current for how long, and what to do when charging is complete) depends on the size and type of the battery being charged. Some battery types have high tolerance for overcharging (i.e., continued charging after the battery has been fully charged) and can be recharged by connection to a constant voltage source or a constant current source, depending on battery type. Simple chargers of this type must be manually disconnected at the end of the charge cycle. Other battery types use a timer to cut off when charging should be complete. Other battery types cannot withstand over-charging, becoming damaged (reduced capacity, reduced lifetime), over heating or even exploding. The charger may have temperature or voltage sensing circuits and a microprocessor controller to safely adjust the charging current and voltage, determine the state of charge, and cut off at the end of charge.

Chargers may elevate the output voltage proportionally with current to compensate for impedance in the wires.[3]

A trickle charger provides a relatively small amount of current, only enough to counteract self-discharge of a battery that is idle for a long time. Some battery types cannot tolerate trickle charging; attempts to do so may result in damage. Lithium-ion batteries cannot handle indefinite trickle charging.[4]

Slow battery chargers may take several hours to complete a charge. High-rate chargers may restore most capacity much faster, but high rate chargers can be more than some battery types can tolerate. Such batteries require active monitoring of the battery to protect it from overcharging. Electric vehicles ideally need high-rate chargers. For public access, installation of such chargers and the distribution support for them is an issue in the proposed adoption of electric cars.


See also: Battery (electricity) § C rate

Charge and discharge rates are often given as C or C-rate, which is a measure of the rate at which a battery is charged or discharged relative to its capacity. The C-rate is defined as the charge or discharge current divided by the battery's capacity to store an electrical charge. While rarely stated explicitly, the unit of the C-rate is h−1, equivalent to stating the battery's capacity to store an electrical charge in unit hour times current in the same unit as the charge or discharge current. The C-rate is never negative, so whether it describes a charging or discharging process depends on the context.

For example, for a battery with a capacity of 500 mAh, a discharge rate of 5000 mA (i.e., 5 A) corresponds to a C-rate of 10C, meaning that such a current can discharge 10 such batteries in one hour. Likewise, for the same battery a charge current of 250 mA corresponds to a C-rate of C/2, meaning that this current will increase the state of charge of this battery by 50% in one hour.[5]

Since the unit of the C-rate is typically implied, some care is required when using it to avoid confusing it with the battery's capacity to store a charge, which in the SI has unit coulomb with unit symbol C.

If both the (dis)charge current and the battery capacity in the C-rate ratio is multiplied by the battery voltage, the C-rate becomes a ratio of the (dis)charge power to the battery's energy capacity. For example, when the 100 kWh battery in a Tesla Model S P100D is undergoing supercharging at 120 kW the C-rate is 1.2C and when that battery delivers its maximum power of 451 kW, its C-rate is 4.51C.

All charging and discharging of batteries generates internal heat, and the amount of heat generated is roughly proportional to the current involved (a battery's current state of charge, condition / history, etc. are also factors). As some batteries reach their full charge, cooling may also be observed.[6] Battery cells which have been built to allow higher C-rates than usual must make provision for increased heating. But high C-ratings are attractive to end users because such batteries can be charged more quickly, and produce higher current output in use. High C-rates typically require the charger to carefully monitor battery parameters such as terminal voltage and temperature to prevent overcharging and so damage to the cells. Such high charging rates are possible only with some battery types. Others will be damaged or possibly overheat or catch fire. Some batteries may even explode.[citation needed] For example, an automobile SLI (starting, lighting, ignition) lead-acid battery carries several risks of explosion.


Simple charger[edit]

A simple charger works by supplying a constant DC or pulsed DCpower source to a battery being charged. A simple charger typically does not alter its output based on charging time or the charge on the battery. This simplicity means that a simple charger is inexpensive, but there are tradeoffs. Typically, a carefully designed simple charger takes longer to charge a battery because it is set to use a lower (i.e., safer) charging rate. Even so, many batteries left on a simple charger for too long will be weakened or destroyed due to over-charging. These chargers also vary in that they can supply either a constant voltage or a constant current, to the battery.

Simple AC-powered battery chargers usually have much higher ripple current and ripple voltage than other kinds of battery chargers because they are inexpensively designed and built. Generally, when the ripple current is within a battery's manufacturer recommended level, the ripple voltage will also be well within the recommended level. The maximum ripple current for a typical 12 V 100 Ah VRLA battery is 5 amps. As long as the ripple current is not excessive (more than 3 to 4 times the battery manufacturer recommended level), the expected life of a ripple-charged VRLA battery will be within 3% of the life of a constant DC-charged battery.[7]

Fast charger[edit]

See also: Quick Charge

Fast chargers make use of control circuitry to rapidly charge the batteries without damaging any of the cells in the battery. The control circuitry can be built into the battery (generally for each cell) or in the external charging unit, or split between both. Most such chargers have a cooling fan to help keep the temperature of the cells at safe levels. Most fast chargers are also capable of acting as standard overnight chargers if used with standard NiMH cells that do not have the special control circuitry.

Three stage charger[edit]

See also: IUoU battery charging

To accelerate the charging time and provide continuous charging, an intelligent charger attempts to detect the state of charge and condition of the battery and applies a 3-stage charging scheme. The following description assumes a sealed lead acid traction battery at 25 °C. The first stage is referred to as "bulk absorption"; the charging current will be held high and constant and is limited by the capacity of the charger. When the voltage on the battery reaches its outgassing voltage (2.22 volts per cell) the charger switches to the second stage and the voltage is held constant (2.40 volts per cell). The delivered current will decline at the maintained voltage, and when the current reaches less than 0.005C the charger enters its third stage and the charger output will be held constant at 2.25 volts per cell. In the third stage, the charging current is very small 0.005C and at this voltage the battery can be maintained at full charge and compensate for self-discharge.

Induction-powered charger[edit]

Main article: Inductive charging

Inductive battery chargers use electromagnetic induction to charge batteries. A charging station sends electromagnetic energy through inductive coupling to an electrical device, which stores the energy in the batteries. This is achieved without the need for metal contacts between the charger and the battery. Inductive battery chargers are commonly used in electric toothbrushes and other devices used in bathrooms. Because there are no open electrical contacts, there is no risk of electrocution. Nowadays it is being used to charge wireless phones.

Smart charger[edit]

Example of a smart charger for AA and AAA batteries with integrated display for status monitoring.

A smart charger can respond to the condition of a battery and modify its charging parameters accordingly, whereas "dumb" chargers apply a steady voltage, possibly through a fixed resistance. It should not be confused with a smart battery that contains a computer chip and communicates digitally with a smart charger about battery condition. A smart battery requires a smart charger (see Smart Battery Data).

Some smart chargers can also charge "dumb" batteries, which lack any internal electronics.

The output current of a smart charger depends upon the battery's state. An intelligent charger may monitor the battery's voltage, temperature or charge time to determine the optimum charge current or terminate charging.

For Ni-Cd and NiMH batteries, the voltage of the battery increases slowly during the charging process, until the battery is fully charged. After that, the voltage decreases, which indicates to an intelligent charger that the battery is fully charged. Such chargers are often labeled as a ΔV, "delta-V," or sometimes "delta peak" charger, indicating that they monitor voltage change. This can cause even an intelligent charger not to sense that the batteries are already fully charged, and continue charging. Overcharging of the batteries may result. Many intelligent chargers employ a variety of cut-off systems to prevent overcharging.

A typical smart charger fast-charges a battery up to about 85% of its maximum capacity in less than an hour, then switches to trickle charging, which takes several hours to top off the battery to its full capacity.[8]

Motion-powered charger[edit]

Linear induction flashlight, charged by shaking along its long axis, causing magnet (visible at right)to slide through a coil of wire (center)to generate electricity

Several companies have begun making devices that charge batteries using energy from human motion such as walking. One made by Tremont Electric, consists of a magnet held between two springs that can charge a battery as the device is moved up and down. Such products have not yet achieved significant commercial success.[9]

A pedal-powered charger for mobile phones, fitted into desks has been created for installation in public spaces, such as airports, railway stations and universities. They have been installed in a number of countries on several continents.[10]

Pulse charger[edit]

Main article: Battery regenerator

Some chargers use pulse technology, in which a series of electrical pulses is fed to the battery. The DC pulses have a strictly controlled rise time, pulse width, pulse repetition rate (frequency) and amplitude. This technology works with any size and type of battery, including automotive and valve-regulated ones.[11]

With pulse charging, high instantaneous voltages are applied without overheating the battery. In a Lead–acid battery, this breaks down lead-sulfate crystals, thus greatly extending the battery service life.[12]

Several kinds of pulse chargers are patented.[13][14][15] Others are open source hardware.

Some chargers use pulses to check the current battery state when the charger is first connected, then use constant current charging during fast charge, then use pulse mode to trickle charge it.[16]

Some chargers use "negative pulse charging," also called "reflex charging" or "burp charging." These chargers use both positive and brief negative current pulses. There is no significant evidence that negative pulse charging is more effective than ordinary pulse charging.

Solar charger[edit]

Main article: Solar charger

Further information: Energy harvesting

VartaSolar Charger Model 57082 with two 2100 mAh Ni-MH rechargeable batteries

Solar chargers convert light energy into low voltage DC current. They are generally portable, but can also be fixed mounted. Fixed mount solar chargers are also known as solar panels. These are often connected to the electrical grid via control and interface circuits, whereas portable solar chargers are used off-grid (i.e. cars, boats, or RVs).

Although portable solar chargers obtain energy only from the sun, they some can charge in low light like at sunset). Portable solar chargers are often used for trickle charging, though some can completely recharge batteries.

Timer-based charger[edit]

The output of a timer charger is terminated after a predetermined time interval. Timer chargers were the most common type for high-capacity Ni-Cd cells in the late 1990s to charge low-capacity consumer Ni-Cd cells.

Often a timer charger and set of batteries could be bought as a bundle and the charger time is set for those batteries specifically. If batteries of lower capacity are charged, then they would be overcharged, and if batteries of higher capacity were timer-charged, they would not reach full capacity.

Timer based chargers also had the drawback that charging batteries that were not fully discharged would result in over-charging.

Trickle charger[edit]

Main article: Trickle charging

A trickle charger is typically low-current (usually between 5–1,500 mA). They are generally used to charge small capacity batteries (2–30 Ah). They are also used to maintain larger capacity batteries (> 30 Ah) in cars and boats. In larger applications, the current of the battery charger is only sufficient to provide trickle current. Depending on the technology of the trickle charger, it can be left connected to the battery indefinitely. Some battery types are not suitable for trickle charging. For instance, most Li-ion batteries cannot be safely trickle charged and can cause a fire or explosion.

Universal battery charger–analyzer[edit]

The most sophisticated chargers are used in critical applications (e.g. military or aviation batteries). These heavy-duty automatic “intelligent charging” systems can be programmed with complex charging cycles specified by the battery manufacturer. The best are universal (i.e. can charge all battery types), and include automatic capacity testing and analyzing functions.

USB-based charger[edit]

Australian and New Zealand power socket with USB charger socket

See also: USB § Power, and ISO 4165

Since the Universal Serial Bus specification provides five-volt power, it is possible to use a USB cable to connect a device to a power supply. Products based on this approach include chargers for cellular phones, portable digital audio players, phone power bank tablet computers. They may be fully compliant USB peripheral devices or uncontrolled, simple chargers.

Power bank[edit]


This section needs expansion. You can help by adding to it. (September 2020)

Single-cell USB power bank
Power bank with digital charging state display

A power bank is a portable device that can supply power from its built-in battery, typically through a USB port.

Power banks have various sizes and typically contain 18650 battery cells. The smallest power banks have a single cell. Moderately sized ones for mobile phones usually have few cells in a parallel circuit, and large ones additionally in two series.

Power banks are popular for charging smaller battery-powered devices with USB ports such as mobile phones and tablet computers and can be used as a power supply for various USB-powered accessories such as lights, small fans and external digital camera battery chargers. They usually recharge with a USB power supply. More recent power banks use USB-C and may feature an additional USB-B micro port for backwards compatibility.

The power bank includes a control circuit that both regulates charging of the battery and converts the battery voltage to 5.0 volts for the USB port.[citation needed] Power banks may be able to detect a connection and power on automatically. If the current load is under a model-specific threshold for a specific duration, a power bank may power down automatically.[17]

Charging state is typically indicated through four LED lamps for each quartal, whereas some higher-end models feature an exact percentage display.[18][19]

Some power banks are able to deliver power wirelessly, some are equipped with an LED flashlight for casual near-distance illumination when necessary, and some have a pass-through charging feature which allows providing power through their USB ports while being charged themselves simultaneously.[20]

Some larger power banks have DC connector (or barrel connector) for higher power demands such as laptop computers.

Battery cases[edit]

Battery cases are small power banks attached to the rear side of a mobile phone like a case. Power may be delivered through the USB charging ports,[21] or wirelessly.[22]

Battery cases also exist in the form of a camera grip accessory, as was for the Nokia Lumia 1020.[23]

For mobile phones with removable rear cover, extended batteries exist. These are larger internal batteries attached with a dedicated, more spacious rear cover replacing the default one. A disadvantage is incompatibility with other phone cases while attached.[24]


Since a battery charger is intended to be connected to a battery, it may not have voltage regulation or filtering of the DC voltage output; it is cheaper to make them that way. Battery chargers equipped with both voltage regulation and filtering are sometimes termed battery eliminators.

Battery charger for vehicles[edit]

There are two main types of chargers used for vehicles:

Chargers for car batteries come in varying ratings. Chargers that are rated up to two amperes may be used to maintain charge on parked vehicle batteries or for small batteries on garden tractors or similar equipment. A motorist may keep a charger rated a few amperes to ten or fifteen amperes for maintenance of automobile batteries or to recharge a vehicle battery that has accidentally discharged. Service stations and commercial garages will have a large charger to fully charge a battery in an hour or two; often these chargers can briefly source the hundreds of amperes required to crank an internal combustion engine starter.

Electric vehicle batteries[edit]

Electric vehicle battery chargers (ECS) come in a variety of brands and characteristics. These chargers vary from 1 kW to 7.5 kW maximum charge rate. Some use algorithm charge curves, others use constant voltage, constant current. Some are programmable by the end user through a CAN port, some have dials for maximum voltage and amperage, some are preset to specified battery pack voltage, amp-hour and chemistry. Prices range from $400 to $4500.

A 10 amp-hour battery could take 15 hours to reach a fully charged state from a fully discharged condition with a 1 amp charger as it would require roughly 1.5 times the battery's capacity.

Public EV charging stations provide 6 kW (host power of 208 to 240 VAC off a 40 amp circuit). 6 kW will recharge an EV roughly 6 times faster than 1 kW overnight charging.

Rapid charging results in even faster recharge times and is limited only by available AC power, battery type, and the type of charging system.[25]

Onboard EV chargers (change AC power to DC power to recharge the EV's pack) can be:

  • Isolated: they make no physical connection between the A/C electrical mains and the batteries being charged. These typically employ some form of inductive connection between the grid and a charging vehicle. Some isolated chargers may be used in parallel. This allows for an increased charge current and reduced charging times. The battery has a maximum current rating that cannot be exceeded
  • Non-isolated: the battery charger has a direct electrical connection to the A/C outlet's wiring. Non-isolated chargers cannot be used in parallel.

Power-factor correction (PFC) chargers can more closely approach the maximum current the plug can deliver, shortening charging time.

Charge stations[edit]

Main article: Charging station

Project Better Place was deploying a network of charging stations and subsidizing vehicle battery costs through leases and credits until filing for bankruptcy in May 2013.

Auxiliary charger designed to fit a variety of proprietary devices

Induction-powered charging[edit]

Researchers at the Korea Advanced Institute of Science and Technology (KAIST) have developed an electric transport system (called Online Electric Vehicle, OLEV) where the vehicles get their power needs from cables underneath the surface of the road via inductive charging, (where a power source is placed underneath the road surface and power is wirelessly picked up on the vehicle itself.[26]

Mobile phone charger[edit]

Main article: Common external power supply

See also: USB § Power

Micro USB mobile phone charger
Charger for automobile auxiliary power outlets
Mobile phone charging station

Most mobile phone chargers are not really chargers, only power adapters that provide a power source for the charging circuitry which is almost always contained within the mobile phone. Older ones are notoriously diverse, having a wide variety of DC connector-styles and voltages, most of which are not compatible with other manufacturers' phones or even different models of phones from a single manufacturer. Some higher-end models feature multiple ports are equipped with a display which indicates output current.[27] Some support communication protocols for charging parameters such as Qualcomm Quick Charge or MediaTek Pump Express.

Chargers for "12V" automobile auxiliary power outlet may support input voltages of up to 24 or 32 Volts (direct current) to ensure compatibility, and be equipped with a display to monitor current or the voltage of the vehicle's electrical system.[28]

China, the European Commission and other countries are making a national standard on mobile phone chargers using the USB standard.[29] In June 2009, 10 of the world's largest mobile phone manufacturers signed a Memorandum of Understanding to develop specifications for and support a microUSB-equipped common External Power Supply td bank heloc customer service for all data-enabled mobile phones sold in the EU.[30] On October 22, 2009, the International Telecommunication Union announced a standard for a universal charger for mobile handsets (Micro-USB).[31]

Stationary battery plants[edit]

Telecommunications, electric power, and computer uninterruptible power supply facilities may have very large standby battery banks (installed in battery rooms) to maintain critical loads for several hours during interruptions of primary grid power. Such chargers are permanently installed and equipped with temperature compensation, supervisory alarms for various system faults, and often redundant independent power supplies and redundant rectifier systems. Chargers for stationary battery plants may have adequate voltage regulation and filtration and sufficient current capacity to allow the battery to be disconnected for maintenance, while the charger supplies the direct current (DC) system load. Capacity of the charger is specified to maintain the system load and recharge a completely discharged battery within, say, 8 hours or other interval.

Prolonging battery life[edit]

A properly designed charger can allow batteries to reach their full cycle life.Excess charging current, lengthy overcharging, or cell reversal in a multiple cell pack cause damage to cells and limit the life expectancy of a battery.

Most modern cell phones, laptop and tablet computers, and most electric vehicles use Lithium-ion batteries.[32] These batteries last longest if the battery is frequently charged; fully discharging the cells will degrade their capacity relatively quickly, but most such batteries are used in equipment which can sense the approach of full discharge and discontinue equipment use.[citation needed] When stored after charging, lithium battery cells degrade more while fully charged than if they are only 40-50% charged. As with all battery types, degradation also occurs faster at higher temperatures. Degradation in lithium-ion batteries is caused by an increased internal battery resistance often due to the cell oxidation. This decreases the efficiency of the battery, resulting in less net current available to be drawn from the battery.[citation needed] However, if Li-ION cells are discharged below a certain voltage a chemical reaction occurs that make them dangerous if recharged, which is why many such batteries in consumer goods now have an "electronic fuse" that permanently disables them if the voltage falls below a set level. The electronic fuse circuitry draws a small amount of current from the battery, which means that if a laptop battery is left for a long time without charging it, and with a very low initial state of charge, the battery may be permanently destroyed.

Motor vehicles, such as boats, RVs, ATVs, motorcycles, cars, trucks, etc. have used lead–acid batteries. These batteries employ a sulfuric acidelectrolyte and can generally be charged and discharged without exhibiting memory effect, though sulfation (a chemical reaction in the battery which deposits a layer of sulfates on the lead) will occur over time. Typically sulfated batteries are simply replaced with new batteries, and the old ones recycled. Lead–acid batteries will experience substantially longer life when a maintenance charger is used to "float charge" the battery. This prevents the battery from ever being below 100% charge, preventing sulfate from forming. Proper temperature compensated float voltage should be used to achieve the best results.

See also[edit]


  1. ^"Recharger definition and meaning - Collins English Dictionary". Archived from the original on 30 November 2016. Retrieved 26 March 2017.
  2. ^"recharge - definition of recharge in English - Oxford Dictionaries". Retrieved 26 March 2017.
  3. ^Charger with output voltage compensation – United States Patent 7602151
  4. ^Phil Weicker, A Systems Approach to Lithium-Ion Battery Management, Artech House, 2013 ISBN 1608076598 page 26
  5. ^"A Guide to Understanding Battery Specifications MIT Electric Vehicle Team"(PDF). December 2008. Retrieved May 10, 2017.
  6. ^"LM2576,LM3420,LP2951,LP2952 Battery Charging"(PDF). July 2018. Retrieved July 29, 2018.
  7. ^"Effects of AC Ripple Current on VRLA Battery Life" by Emerson Network Power
  8. ^Dave Etchells. "The Great Battery Shootout".
  9. ^Martin LaMonica, CNET. "Motion-powered gadget charger back on track." Jul 1, 2011. Retrieved Jul 1, 2011.
  10. ^"Delayed at the station? Get pedalling to charge your phone". Connexion France. 4 April 2017.
  11. ^"AN913: Switch-Mode, Linear, and Pulse Charging Techniques for Li+ Battery in Mobile Phones and PDAs". Maxim. 2001.
  12. ^"Lead–acid battery sulfation". Archived from the original on 2007-04-02.
  13. ^""fast pulse battery charger" patent". 2003. Archived from the original on 2011-02-28. Retrieved 2008-01-21.
  14. ^ "Battery charger with current pulse regulation" patented 1981 United States Patent 4355275
  15. ^ "Pulse-charge battery charger" patented 1997 United States Patent 5633574
  16. ^"Pulse Maintenance charging."Archived March 9, 2012, at the Wayback Machine
  17. ^"Port detection for power banks". Texas Instruments. April 2016. Retrieved 2021-09-13.
  18. ^"INIU Portable Power Bank 20,000mAh Battery Charger". Maris Review. 10 June 2021. Retrieved 22 August 2021.
  19. ^Barton, Michael (2018-10-20). "Die RealPower PB-15000C Powerbank im Test - Techtest". (in German). Retrieved 22 August 2021.
  20. ^"How Pass Through Tech Lets You Use Power Banks In Creative Ways". RAVPower. 2018-06-01. Retrieved 2020-09-06.
  21. ^Stein, Scott. "Apple Smart Battery Case for iPhone 6S review: Addressing the iPhone's biggest weakness". CNET.
  22. ^"Galaxy Note 7 S View Standing Cover and Battery Pack hands on". Android Authority. 2 August 2016.
  23. ^"IRL: Testing the Nokia Lumia 1020's optional camera grip / battery case". Engadget. 2013-09-16.
  24. ^Klug, Brian (2013-07-23). "Samsung Galaxy S 4 ZeroLemon 7500 mAh Extended Battery Review".
  25. ^Fuji Heavy Speeds Up Recharging of R1e EV. Green Car Congress (2007-09-18). Retrieved on 2011-11-11.
  26. ^Korean electric vehicle solution. Retrieved on 2011-11-11.
  27. ^"Index of tested and reviewed USB power supplies/chargers". lygte-info. Retrieved 22 August 2021.
  28. ^ Model: YSY-C009 Qualcomm Quick Charge 3.0 Input: 12-32V Output: 4USB 5V-7A ( 35W Max ) / 1USB 9V/12V-1.8A
  29. ^China to work out national standard for mobile phone chargers. Retrieved on 2011-11-11.
  30. ^PC World:Universal Chargers are a Good Start Jan 2009
  31. ^Oct 22, 2009, ITU press release Universal charger for mobile phone handsets
  32. ^Mansoori, G. Ali; Enayati, Nader; Agyarko, L. Barnie (2015-11-05). Energy: Sources, Utilization, Legislation, Sustainability, Illinois as Model State. World Scientific. ISBN .

Alex Wawro is a lifelong tech and games enthusiast with more than a decade of experience covering both for outlets like Game Developer, Black Hat, and PC World magazine. He currently serves as a senior editor at Tom's Guide covering all things computing, from laptops and desktops to keyboards and mice. 


A power bank is a portable battery designed to recharge electronic gadgets when you don’t have access to a regular wall charger. Ranging in size from slim, pocket-sized devices up to larger, high-capacity power banks – they can be used to charge cell phones, tablets, cameras, portable speakers, gaming consoles, or even laptops.

So the concept of a power bank is pretty simple: a rechargeable battery that can be used to charge other devices. However, even if they seem pretty basic, power banks can have some pretty complex technologies built-in.

For example, in order to reduce the risk of malfunctioning, a lot of safety features are added: overcharge protection, over-discharge protection, short circuit protection, etc.

Other types of technologies frequently seen in power banks are pass-through charging, wireless charging, and fast charging technologies such as Qualcomm Quick Charge, Power Delivery, or PowerIQ. Some newer models are even featuring futuristic battery techs such as GaN or Graphene technology.

How does a power bank work?

Since power banks are basically regular batteries with some extra features, they work just like any other rechargeable battery. They first store energy up to their maximum capacity and then release it when connected to a different device that needs recharging. That’s the basic gist of it.

Of course, in terms of circuitry, they can be quite complex devices. Besides charging and recharging they also have other features such as safety features, power indicators, quick charging technologies, etc.

What are the different types of power banks?

Power banks come in many different shapes and sizes to suit different budgets and power needs. There are portable chargers that can be used for just about every device. Most people buy power banks to use them for their cell phones, tablets, or laptops. But some portable chargers can also be used for devices such as drones, mini-fridges, or even CPAP sleep apnea machines.

New portable charger models are coming out every day with improved charging technologies. Some power banks even work by harnessing solar energy while others double as a protective case that also charges your phone. In terms of shape, the most popular ones are cylindrical or rectangular, similar to a smartphone or a deck of playing cards.

How to charge a power bank

All power banks come with a power input port. The type of port can be different based on the model but micro USB was the most popular one until recently. However, micro USB is slowly being replaced by USB type C ports, which seems to be the new standard for the coming years. So, if you’re looking to buy a new power bank, our advice is to look for one with has a USB type C input port. Here’s a curated list of some of the best USB C power banks.

The most efficient way to charge a power bank is to use a wall charger that can deliver a high power output. Using a low-quality wall charger that only delivers 2A for example, can extend the recharging time for several hours. For this reason, we have put together a list of the best GaN chargers and a different one of the best chargers with Quick Charge 3.0 and 4.0. Another way to charge a power bank is by using a charging station.

Other ways to charge a power bank are using your laptop USB port, a car cigarette lighter, or using a solar charger such as the Anker 21W. However, all these methods are slower and you should avoid them unless you can’t access a wall charger.

Make sure to also read our guide on how to use a power bank for the first time.

How long does it take to charge a power bank?

This is largely dictated by the size of your power bank’s capacity. The larger the capacity of the power bank you decide to purchase, the longer it may take to charge. But other factors can influence the charging speed too, such as the charging technology used. For example, power banks with fast charging features or those built based on the new graphene or GaN technologies will charge much faster than usual.

As a rule of thumb, for a power bank of 10000mAh, the average recharging time is around 4-6h. The fastest ones can charge in under 1h but expect to pay a premium price for that. And the slowest ones might take as much as 8h to recharge. It’s best to avoid them if you can find faster-charging options at a similar price point.

How many times can a power bank charge my device?

This comes down to the capacity of your device and the power bank/portable charger. A power bank is measured by its capacity, which is rated in mAh (milliampere-hour). Generally, the higher the mAh rating of your power bank or portable charger, the more power it will have to recharge your devices. A good rule of thumb is to look at the mAh rating of the devices you want to charge, and purchase a power bank that has an equal rating (preferably higher).

For example, the iPhone 11 has a 3110mAh rated battery. The XCentz Wingman has a mAh capacity of 5000mAh. This would safely charge your phone back to 100% battery. However it is not an exact science, there are factors to consider such as the power bank’s efficiency rating and the condition of the battery in the device you are charging. Read more about the real battery capacity of a power bank.

The following set of figures can be used as a rough guide to what kind of recharging capacity a power bank may give you.

Device Charge Times Example

Power Bank RatingMobile PhoneTablet
2500mAhApprox. 1 full chargeApprox. 25%
5200mAhApprox. 2 full chargesApprox. 50%
10000mAh4 full chargesAt least 100% full charge

On ou5 product review pages such as the RAVPower 20000mAh PD 60W, we even have an automatic calculator that can tell you exactly how many times that specific power bank can charge your specific smartphone model:

If you don’t know which power bank you want, then you can use our general mAh calculator.

We’re discussing also this subject in more detail here: How many mAh do you need to charge your phone?

Is a Power Bank and a Portable Charger the same thing?

YES! They are basically one and the same thing 😊

Different terms such as power bank, portable charger, portable phone charger, external battery, external battery pack, etc. all refer to the same type of device. If it’s a battery that you can use to power a device with its own battery without using a wall socket, it’s a power bank.

Read more about these two terms and about their popularity in our dedicated article: Power Bank or Portable Charger?

What type of batteries do power banks use?

Power banks generally come with either Lithium-Polymer (Li-Po) and Lithium-Ion (Li-Ion) batteries. Of the two Li-Ion power banks are more popular.

In terms of differences between these two types:

  • Lithium-Polymer batteries have a higher energy density but they tend to have a shorter lifespan and are also more expensive to manufacture. They’re also less prone to explosion.
  • Lithium-Ion batteries, on the other hand,  have a slightly lower energy density but they can withstand more charge/discharge cycles and are generally less expensive.

For a more in-depth look at this subject, check out our article: Lithium-ion vs Lithium-polymer power banks. Which is better?

Are you allowed to take power banks on flights?

Yes, you can take power banks and other batteried on flights, however, some conditions apply:

  • you can only take them in your cabin luggage
  • the battery should be 100 Wh or under
  • batteries that are between 100 Wh and 160 Wh need a special permit
  • ideally, the output should be clearly labeled on the device

Read our detailed article for more information about power banks on flights.

Top 10 reasons to buy a power bank

#1 For traveling

Long gone are the days of traveling with nothing but a change of clothes, toiletries, and accessories. We love to travel here at Power Bank Expert – my backpack right now contains the following electronic goodies: MacBook Pro, Kindle Paperwhite, Olympus 4/3 digital camera, JBL portable travel speaker, iPod Touch, Nexus 5, and an iPad Air.

Travelling is all about the journey, and that often means spending a long time on a train/plane/bus/car. Not to mention waiting around at airports, bus stations, and train stations. More often than not you might not have any access to a PowerPoint to recharge your devices. A portable power bank will solve your flat battery blues.

Luckily today’s portable power banks come in some truly travel-friendly sizes. Take the Xcentz 5000mAh. Weighing in at a measly 4.5oz, and measuring only 4.8 x 1 x 1in, it really is lipstick-sized. Small enough to slip in your pocket, this portable charger will not put a big dent in your backpack or suitcase.

#2 For gamers

One thing all these mobile games have in common – is their capacity to kill your cell phone’s battery! But avid gamers don’t only use phones for gameplay time, but dedicated consoles such as the Nintendo Switch. However, modern power banks are more than capable to satisfy even the most power-hungry consoles and extend the game time for hours on end.

#3 For portability

Many people do not realize how small portable power banks and phone chargers are. Many are small enough to fit in a pocket or purse. With pretty much all but the most industrial-strength devices being portable enough to fit in a backpack or shoulder bag.

  • The Poweradd Slim2 5000mAh weighs just 4.4 oz and measures 3.93 x 1.27 x1.20 inches. This will slip into your pocket with ease.
  • A slight step up in size – the Anker Astro E1 5200mAh Candy bar-Sized Ultra Compact Portable Charger is an excellent choice. They weren’t lying when they named it ‘candy bar sized’ – it weighs in at 4.2oz, and measures just 5 x 3.4 x 1.7 inches.

#4 For commuting

I used to have a 1.25-hour train ride to and from work every day, and boy do I wish I’d owned a portable power bank back then! When you’re packed onto a train or a bus, your options are pretty limited in how to kill the time. But having your smartphone/tablet/laptop with you can make that journey absolutely fly by. Owning a portable power bank means you can catch up on Game of Thrones, browse Facebook or read the latest news – and NEVER run out of battery.]

#5 For camping / hiking / fishing

There’s nothing better than escaping into the great outdoors, but what if you want to stay connected to the digital world whilst you’re enjoying all that nature has to offer? You might want to upload your pictures to Instagram, keep your portable speaker playing tunes, or recharge your camera’s batteries. Here’s where a portable power bank can come into its own.

Any portable power bank or phone charger would fit the bill for a trip into the great outdoors, but there are some portable power banks that are purpose-built for the task. The Novoo Explorer 10000mAh is snowproof, dirtproof, drop-proof, and waterproof. Its rugged construction makes it an ideal buy if you often head outdoors.

Or why not keep your electronics charged, and be environmentally friendly at once and buy a solar portable charger? The Nekteck 20W Solar Charger folds out and can be hooked to your backpack as you hike to recharge its batteries straight from the sun. It’s extremely durable, weighs 20oz, and when folded down it measures 11.8 x 6.5in.


FOMO, or Fear of missing out is an emotion you’ve probably experienced before. And FOMO can quickly turn from fear to reality if you’ve run out of battery! If your cell phone is flat you could miss a call about that important job you just applied for. Or maybe a cute guy/girl just sent you a message on Tinder – how to reply if you have no batteries? Eliminate electronic FOMO and buy a portable power bank!

#7 For your hip pocket

In this post, we’ve listed all kinds of reasons and benefits why you should buy a portable power bank. But a really, truly fantastic reason is that they are so affordable! You can buy a high-quality portable power bank from a reputable brand for as little as $10 US. That’s cheaper than:

  • Getting a haircut
  • Going out to dinner
  • Buying a bottle of wine

#8 For music festivals

There’s nothing much more fun than a multi-day music festival, camping with your friends, and watching your favorite bands play. Keeping your batteries charged means you can find your friends when you inevitably lose each other, keep playing music back at your tent once the bands are finished for the night, and keep posting pictures and videos to make all your friends jealous. Make a portable power bank an essential travel companion for this summer festival season!

#9 For your job

Apart from being super-handy in your personal life, portable power banks may well be incredibly helpful for your working life as well. Here are a few careers that will really benefit from the purchase of a portable power bank:

  • Photographers can keep their camera’s batteries juiced up when they’re out on a shoot.
  • Real estate agents are constantly driving all over their hometowns, showing clients properties, and are always on their phones.
  • A job in sales often involves significant amounts of travel, as regions bank login one pass as heavy use of laptops/phones/tablets.
  • People working in trades such as plumbers, electricians, and plumbers need to drive from job site to southeast financial credit union phone number site and are often away from sources of power for long stretches of time.
  • Small business owners need their cell phones to keep their businesses running. Being the owner often necessitates significant amounts of travel.
  • Students also need their electronic devices for their studies. Having your laptop go flat whilst taking notes in a university lecture could really set you back. A portable power bank will make that a problem of the past!

#10 For safety

Cell phones have become indispensable in today’s world. A benefit of your cell phone you might not have taken into consideration is for your own personal safety. Your phone is your link to the outside world. Consider you’re walking home alone at night and you’re being followed by an unsavory looking person. This can be a scary situation, and could potentially be very dangerous. All it takes is one call to the police, or to a friend or family member and they can come to help you.

Now consider that scenario again, and imagine your cell phone’s battery is dead! There’s no way for you to contact anyone for help, and that’s a situation I know I would not like to be in. With a portable power bank or phone charger, you can make sure your cell phone’s battery is ALWAYS topped up. Check out this handy article about ways to stay safe when you’re traveling.

Power bank reviews

If you’re interested in comparing different power bank models, head on to our power bank review section. Otherwise, you can check out our curated list of what we believe to be the current 10 best power banks.

Categories Blog, EducationalИсточник:

The dreaded low-battery notification never seems too far away these days. As our electronics get smaller and slimmer, manufacturers often sacrifice battery capacity, leaving us constantly needing to charge our devices.

Fortunately, keeping a power bank on hand is an easy way to top up on the move, without needing to carry a charger or search around the airport for an available outlet (good luck with that!) 

There are power banks of all shapes and sizes, and each differs in its capacity, output, and features. The best power bank for laptops, for example, will look substantially different from the best options for phones and small electronics. 

That’s why we’ve put together our recommendations for the best portable batteries on the market in 2021, no matter what your requirements are. Want something you can keep in your car for a quick emergency boost? Heading off the grid for a week but have to stay charged? Need to keep your laptop going all day? We’ve got you covered.

Best Power Bank: Anker PowerCore Essential 20000
Best Power Bank: Anker PowerCore Essential 20000
  • Capacity: 20,000mAh
  • Weight: 12.3 ounces (350g)
  • Dimensions: 6.2 x 2.9 x 0.8 inches
  • Maximum output: USB-A: 15W total
  • Ports: 2x USB-A (output), 1x USB C (input), 1x micro-USB (input)
  • Pass-through charging: No
Best Laptop Power Bank: Anker PowerCore+ 26800
Best Laptop Power Bank: Anker PowerCore+ 26800
  • Capacity: 26,800mAh
  • Weight: 12.3 ounces (350g)
  • Dimensions: 7.1 x 3.1 x 0.9 inches
  • Maximum output: USB C PD: 45W, USB-A: 12W individual, 15W total
  • Ports: 2x USB-A (output), 1x USB C (input/output)
  • Pass-through charging: No
Best Power Bank with AC Outlet: RavPower PD Pioneer
Best Power Bank with Fake wells fargo cashiers check Outlet: RavPower PD Pioneer
  • Capacity: 20,000mAh (74Wh)
  • Weight: 1.46 pounds (662g)
  • Dimensions: 5.8 x 2.7 x 2.7 inches
  • Maximum output: AC: 80W (100W max), USB C PD: 30W, USB-A: 18W
  • Ports: 1x AC (output), 1x USB C (input/output), 1x USB-A (output)
  • Pass-through charging: No
Best Power Bank for Camping: Jackery Explorer 160
Best Power Bank for Camping: Jackery Explorer 160
  • Capacity: 46,400mAh
  • Weight: 3.8 pounds (1.7kg)
  • Dimensions: 7.4 x 4.6 x 6.7 inches
  • Maximum output: AC: 100W (150W max), USB C: 15W, USB-A: 12W each (max USB output 30W)
  • Ports: 1x USB C (output), 2x USB-A (output), 12V DC (output), 1 x AC (output)
  • Pass-through charging: Yes

Best Power Bank: Anker PowerCore Essential 20000

Anker Portable Charger, PowerCore Essential 20000mAh Power Bank with PowerIQ Technology and USB-C (Input Only), Durable External Battery Pack Compatible with iPhone, Samsung, iPad, and More.

Anker is a leader in the portable battery market, and the PowerCore Essential one of its most versatile products. The Essential’s 20,000mAh capacity makes it one of the best high-capacity power banks on the market: for context, this provides enough juice to fully charge a typical smartphone four to five times. 

Despite its high capacity, the PowerCore Essential remains relatively compact at 6.2 x 2.9 x 0.8 inches and weighs just over twelve ounces. It features a rugged, durable design that can stand up to general wear and tear. 

The PowerCore Essential can charge two devices at once via the dual USB-A ports. You’ll get 2.4A (12W) out of either port, with a combined maximum of 3A (15W) when using both.

The unit also has USB C and microUSB ports, but these are input-only. This means that you can charge the battery via USB C or microUSB, but you can only charge devices from the USB-A ports. 

This portable charger also has some slick charging features common to most Anker power banks. PowerIQ and VoltageBoost technologies combine to deliver an optimized charge to your devices, while “trickle-charging” mode is optimized for efficiently charging low-power devices like Bluetooth headphones. 

The PowerCore Essential comes with Anker’s standard 18-month limited warranty, as well as a travel pouch to protect it on the go. It doesn’t come with a wall charger or USB C cable, however. 

The only real downside is the lack of USB C charging: as mentioned, the USB C port is input-only. If you’re happy to lose microUSB charging and one of the USB-A ports, Anker makes a similar PowerCore Essential PD that does include USB C output.

  • 4-5 full charges of most phones
  • Can charge power bank from either microUSB or USB C
  • Simultaneous charging of two devices
  • 18 month warranty
Buy on Amazon

Best Laptop Power Bank: Anker PowerCore+ 26800

Anker PowerCore+ 26800mAh PD 45W with 60W PD Charger, Power Delivery Portable Charger Bundle for USB C MacBook Air/Pro/Dell XPS, iPad Pro 2018, iPhone 12 / Mini / 11/ Pro / XS Max / X / 8, and More

If you’re looking to charge laptops and other large electronic devices, standard power banks won’t cut it. You’ll need something more substantial, like the Anker PowerCore+. This unit has a phone power bank capacity and up to 45W output, enough power to fully charge a 13” Dell XPS or a 13” MacBook Pro. 

That capacity also happens to be just under the legal limit for airplane use, so this is among the best TSA-approved options, and one of the best power banks for travel. 

This unique laptop power bank has dual output ports: a 45W USB C port for modern laptops, and 2x 15W USB-A ports for smaller electronic devices. The laptop output is substantial enough to charge most laptops while using them, which isn’t always the case with competing models. 

Because the laptop port is USB C, this works best for newer laptops with USB C charging. It doesn’t have a standard AC outlet that will support older laptops that charge via a power brick: if that’s something you’re after, take a look at the RavPower PD Pioneer below.

This unit comes with a 60W wall charger, meaning that despite its huge capacity, it takes under 3.5 hours to fully charge itself from empty. Combine that with USB C Power Delivery (PD) support for speedy device charging, and you’ve got arguably the best fast charging power bank on the market.

  • Huge capacity
  • Fully charge a 13-inch MacBook Pro or Dell XPS
  • USB C PD (45W) and dual USB-A (15W) ports
  • Comes with 60W wall charger
  • Designed for newer USB C laptops, so no standard AC outlet for older laptop chargers
Buy on Amazon

Best Power Bank with AC Outlet: RavPower PD Pioneer

RAVPower PD Pioneer 80W

If you have an older laptop that needs to charge via an AC outlet, or just want a versatile charger that can power almost anything, the RavPower PD Pioneer is a great option. 

This compact power bank is one of few on the market that actually has a built-in AC outlet, which can put out a sustained 80W of power. It also has USB-A (18W) and USB C (30W) ports, making it a versatile option for charging most devices.

With a capacity of 20,000mAh, this power bank will give close to one full charge of most 13″ laptops. As the name suggests, it also has USB PD (Power Delivery) technology, a fast-charging feature that can deliver a surprising amount of power, surprisingly quickly. Depending on the device, PD can cut recharge time by up to 60%.

At less than 1.5 pounds, it’s relatively lightweight by the standards of this type of power bank, and can itself be fully charged from a high-speed wall charger in under three hours. 

The main downside is the cooling fan. While it helps to keep the device at a reasonable temperature, it can be a bit noisy. For more information, check out our full review of this unit. We also covered several other portable laptop chargers for a range of different requirements.

  • Relatively compact
  • Includes AC outlet to charge almost anything, including older laptops
  • Useful capacity
  • Versatile charging via AC, USB C, and USB-A
  • Cooling fan can be noisy
  • No wall charger included

Buy from RAVPower

Best Wireless Power Bank: Anker Wireless PowerCore III

Anker PowerCore III 10K Wireless Portable Charger with Qi-Certified 10W Wireless Charging and 18W USB-C Quick Charge for iPhone 13, 12, Mini, Pro, iPad, AirPods, and More

Another day, another excellent Anker power bank, but this time it’s wireless. 

The 10,000mAh Anker Wireless PowerCore III is our pick for the best wireless power bank. If your phone supports it, you can charge wirelessly via the charging pad at up 10W. Using the Qi standard, it’s widely compatible with recent iPhones, many Android smartphones, and other devices. 

If your device doesn’t support wireless charging, never fear: both the USB C and USB-A ports provide a backup option. You’ll get up to 18W output from the USB C port, so it’s also a way of ensuring faster charging even if your device does have Qi support.

That USB C port is also how you charge the power bank itself, again at up to 18W if you’ve got an appropriate wall charger. Unfortunately Anker doesn’t provide one in the box, so you’ll need to use one you already own or buy an appropriate model. You can also charge from a laptop in a pinch.

A particularly useful feature is pass-through charging, where the power bank can charge devices while it itself is charging. This basically means that you can use the PowerCore in place of a standard Qi charging dock, and simply leave it plugged in all the time. 

  • Qi charging
  • Pass-through charging: can charge device and power bank simultaneously
  • 2 USB ports for charging other devices, at up to 18W
  • Doesn’t include a wall charger
Buy on Amazon

Best Small Power Bank: JSAUX Portable Phone Charger

Mini Portable Charger 10000mAh, JSAUX 20W PD3.0 Smallest USB-C Power Bank 18W USB-A Fast Charge Battery Pack Compatible with iPhone 13 12 Mini Pro Max 11 11 Pro, Samsung Galaxy S21 S20-Black

The JSAUX mini portable charger is one of the best small power banks on the market. Weighing just 6.3 ounces, the 10,000mAh capacity is enough for around two full phone charges for most smartphones.

Unlike most other small power banks, it offers both USB C and USB A charging ports. Even more unusually, they’re both able to fast-charge your device: you’ll get up to 18W from the USB-A port, and up to 20W out of the USB C PD port.

Usefully, there’s also a trickle-charge mode, for low-power devices like wireless earbuds and smartwatches. Holding down the power button for three seconds enables that mode.

Charging the power bank itself is done via USB C, and if you use a 20W wall charger, it’ll happen in under three hours. Unusually, it has pass-through charging as well, letting you power up one of your devices from the USB-A port while charging the power bank itself from the USB C port.

As small and lightweight as it is, the power bank is an inch thick. That’s totally fine if it’s sitting in your purse or day bag, but feels a little large when it’s in your pocket.

If you’re looking to go even smaller, consider the lipstick-shaped Anker PowerCore 5000 instead. You’ll lose many of the features of the JBAUX, but it weighs a mere 4.8oz, yet still has enough juice for about one full phone charge.

  • Compact, portable design
  • USB C PD and USB-A ports
  • 10000mAh capacity
  • Trickle charging option
  • Reasonably priced
  • Slightly thicker than we’d like
Buy on Amazon

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Best Power Bank for Camping: Jackery Explorer 160 

Jackery Portable Power Station Explorer 160, 167Wh Lithium Battery Solar Generator (Solar Panel Optional) Backup Power Supply with 110V/100W(Peak 150W) AC Outlet for Outdoors Camping Fishing Emergency

Looking for a more off-grid option? If you need plenty of power, the Jackery Explorer 160 is one of the best power banks for camping. It has a wide variety of output options, including AC, USB C, USB-A, and 12v DC, so it can power or charge most anything, up to five devices at once. Talk about glamping! 

It offers a massive 46,400mAh capacity, at least twice the capacity of any of the other power banks on this list. This means it will last for even multi-day camping trips, but for virtually unlimited power, you can use the SolarSaga solar panels (sold separately) to recharge the Explorer power bank anywhere you have sunlight.

The features, reliability, and solar charging capabilities make this a great choice for car camping, and it even makes for a decent emergency power supply to keep at home. At around 4lbs, it’s a bit bulky for backpacking, however, and that size balloons even further if you add the solar panels.

We reviewed the (much) larger Jackery Explorer 1000, along with the companion solar panels, and were impressed by the combination. If you’re in the market for portable batteries for camping but have slightly different needs, we covered a range of alternatives that can do everything from charging your phone to jump-starting your car.

  • Versatile charging options: AC, USB C, USB-A, and 12v DC
  • Huge capacity
  • Charge/power up to 5 devices at once
  • Optional solar panels
Buy on Amazon

Main image via Shutterstock, product images via Amazon

About the Author
Austin Meadows

Austin Meadows

Austin is a digital nomad with a passion for exploring alternative lifestyles and testing the latest technological innovations. Rarely under the same roof for long, when he's not sampling wine and cheese in Bulgaria or downloading the latest travel app, you can find him running, gaming, or cooking up something delicious.

These are the Best Power Banks to Buy

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  • We’ve added several models that we plan to test in late 2021 to the What to look forward to section. We’ll update this guide with our findings as soon as we can.

November 1, 2021

Whether you’re a glued-to-your-screen smartphone owner who can never make it through a day on a full charge, or you just need an occasional battery boost, USB power banks are a panacea for low-battery anxiety. After putting in 15 hours of research and 49 hours of testing, we’ve found the best portable power banks to meet a wide range of needs, chargers that offer you peace of mind whenever wall outlets are out of reach.

The TravelCard Charger is the best portable charger for someone who wants to have an emergency boost of power always on hand. It has the lowest capacity of any power bank we’ve tested—it’s able to charge most phones only to around 30% to 50% full from empty—but it’s unmatched in weight (2 ounces) and size. It’s bigger and thicker than the average credit card but not by much, fitting easily in a wallet or pocket. It has a built-in USB-A cable for you to charge it up and a built-in output phone power bank (either Lightning, Micro-USB, or USB-C, depending on which version you get) to top off your phone or another handheld device with a little boost of power.

The Anker PowerCore 10000 PD Redux lacks the built-in cables that set the TravelCard models apart, but its capacity (10,000 mAh, or enough to fully charge most smartphones three times) is a lot higher. Plus, in addition to a USB-A output port, it has a USB-C Power Delivery (PD) port that enables charging (both input and output) up to 18.8 watts—nearly twice as fast as most power banks we’ve found with built-in cables. This means less time waiting around for your phone, tablet, or other device (and the power bank itself) to fully charge. About the size and shape of a bar of soap, the Redux has a smooth yet grippy texture, and you can easily stow it in a pocket or pouch for portable power on the go.

The Anker PowerCore III Fusion 5K is handy if you want a single, reliable charger that you can plug in the wall to charge your devices overnight and then pack up and carry with you during the day. Its 5,000 mAh capacity is half that of the Redux, but that’s still enough to fully charge most smartphones more than once. At 6.4 ounces, it’s a hair lighter than the Redux, too. It recharges quickly via its USB-C PD port or fold-out AC plug—most models we tested have just one or the other—and it offers fairly fast charging for two devices at a time on the USB-C PD and USB-A ports. If you want a power bank that doubles as a wall charger, this is the best option we’ve found.

Why you should trust me

As the writer of this guide, I spent 15 hours researching and 49 hours testing USB power banks and portable chargers. I’ve been a science journalist for more than seven years, covering a wide variety of topics from particle physics to satellite remote sensing. Since joining Wirecutter in 2017, I’ve reported on solar battery packs, USB-C cables and adapters, portable laptop chargers, and more.

Who this is for

Most people could use a USB power bank or external battery pack—the question is, which one best fits into your habits? Some might need only a small battery to give their phone a boost at the end of the day, while people who travel a lot may be looking to power multiple devices over the course of several days. Rather than always having to track down a wall outlet wherever you go, owning a USB power bank allows you to enjoy a conveniently portable (albeit limited) power supply.

Even if you’re blessed with an abundance of charging options in your daily life—maybe you spend most of your day at home, at the office, or in the car—you could probably still benefit from a portable power bank. Something wallet-sized is great to always have on hand for those unexpected (yet critical) moments when your phone is dying and no outlets are nearby. But if you want something for weekend trips or a regular commute, slightly larger power banks can still fit easily in laptop bags, purses, or large pockets, offering two or more full charges for most smartphones. These power banks are robust yet portable, allowing you to charge other devices, too—wireless headphones, computer mice, keyboards, vaporizers, digital cameras, and more.

When you’re traveling in an unfamiliar place—relying on your phone to guide you and to potentially call for help—a power bank offers added peace of mind. Placing a few of these strategically around the house isn’t a bad idea: You can keep one in your foyer to grab as you’re running out the door, or you can have a power bank near the couch for when you’re cozily curled up under a blanket and you really, really don’t want to get up to plug in your phone.

How we picked

Our top picks for best portable chargers and power banks for phones and tablets sitting next to each other, along with three USB charging cables.

Due to the unfortunate fact that battery technology has failed to keep up with the processing power of modern devices, USB power banks have become an increasingly popular way to help phones and tablets get through the day. You can find tons of brands and models to choose from, so we checked out major retailers like Amazon, Home Depot, and Target—as well as trusted editorial sources such as CNET, PCMag, PCWorld, and TechRadar—to find the most well-known makers of widely available USB power banks. From there, we built out a list of contenders based on the following features:

  • Powerful output and input: For models with USB-C output or input, we preferred those rated for at least 15-watt charging; for models with USB-A output or Micro-USB input, we looked for those rated for 8 watts or more. These capabilities ensure top charging (output) and recharging (input) speeds.
  • Built-in cables: We preferred that the power banks—especially the smaller, low-capacity models—have some type of built-in cable. This feature is indispensable when well integrated because it reduces the number of cables you have to carry around and (eventually, inevitably) disentangle from the rest of your stuff.
  • No heavier than 8 ounces: Power banks should be small and lightweight, making them easy to carry around for an entire day in a wallet, pocket, or bag. We set the weight cutoff at 8 ounces since an iPhone 12 weighs 5.8 ounces and we don’t think most people want to carry something in their pocket or purse that weighs much more than a smartphone.
  • Capacity rating of 1,000 to 10,000 mAh: The capacity rating listed on the power bank tells you roughly how much power it can hold. For reference, an iPhone 12 battery has a capacity of 10 watt-hours (about 2,800 milliampere hours), and a 16-inch MacBook Pro battery has a capacity of 100 Wh (about 28,000 mAh). Power banks with a capacity rating of 10,000 mAh and up tend to be bigger, heavier, and more expensive, so for this guide we primarily focused on lower-capacity power banks—those that offered enough capacity to give your phone a boost of power or to fully charge it several times without weighing you down. Our picks in our guide to the best portable laptop chargers offer higher capacities and AC output ports.
  • At least a one-year warranty: A year is plenty of time to use your power bank and make sure it’s working properly, though longer warranties are of course always preferable.
  • Price: We used a ratio of capacity (mAh) best bb gun dollar to break ties between otherwise similar models.
  • Brand reputation: We favored brands that we’ve had mostly good experiences with in the past in terms of responsive customer support, forex com vs td ameritrade availability, and ability to keep models in stock. We discounted crowdfunded or less-established brands and those lacking a visible web presence or customer support.

This process left us with the following portable battery packs, which we called in for testing:

How we tested

We tested the performance of each power bank in a few key areas, including the following:

  • Weight: We used an Escali Primo Digital Scale to confirm the advertised weight of each power bank.
  • Size: Rather than measure the length, width, and depth of each power bank—which would have been tedious and not terribly meaningful for most people—we considered size in terms of whether a power bank fit inside a wallet, a pocket (we tried a variety of pants, skirt, and jacket pockets), or an accessory pouch.
  • Look and feel: We took note of each power bank’s bulk and its exterior texture. We considered how easy and intuitive its features—such as the power buttons, charging-status lights, built-in cables, fold-out AC plug, or flashlight—were to use.
  • Charging output of USB-A ports: We measured USB-A output by connecting a half-charged power bank to a PortaPow and a Drok USB load tester. We then turned up the amperage of the load tester as far as it could go without overloading the power bank and recorded the volts and amps we measured with the PortaPow to calculate the maximum output (watts).
  • Charging output of USB-C ports: We measured USB-C output by connecting a half-charged power bank to a Total Phase USB Power Delivery Analyzer, an Apple USB-C cable, and a MacBook Pro. We then used the Total Phase Data Center program, checked over the power profile and any errors, and recorded the volts and amps (to calculate the result in watts).
  • USB-C recharging speed: We measured USB-C input by connecting a fully drained power bank to a Total Phase USB Power Delivery Analyzer and a 60 W MacBook Pro charger. We then ran the Total Phase Data Center program, checked over the power profile and any errors, and recorded the volts and amps (to calculate the input in watts).
  • Micro-USB recharging speed: We measured Micro-USB input by connecting a fully drained power bank to a PortaPow USB Power Monitor, an Anker PowerLine Micro-USB cable, and an Anker PowerPort 2 wall charger plugged into a wall outlet. We then recorded the volts and amps we measured with the PortaPow to calculate the input (watts).
  • Nintendo Switch compatibility: Because this popular gaming console is notoriously finicky when it comes to charging, we plugged each of the power banks into a half-charged Switch to make sure they could charge it at least partially. All of our picks (except the original TravelCard Charger, which has only Lightning output) passed this test.

Fits in a wallet: TravelCard Charger and TravelCard Charger (USB-C)

A gray and a black TravelCard Charger, a top pick for best portable chargers and power banks for phones and tablets.

Why we love it: If you want a USB power bank that you can carry around in your wallet or bag for a backup boost of portable power, get the TravelCard Charger for iPhones or the TravelCard Charger (USB-C) for devices that charge via USB-C. Neither model fully phone power bank most smartphones, but either one is good to have in a pinch. For reference, an iPhone 12 requires around 2,800 mAh for a full charge, and these power banks offer only about 1,500 mAh apiece.

These power banks are impressively powerful for how small (not much bigger or thicker than a credit card) and lightweight (less than 2 ounces) they are. And their built-in cables free up space you’d otherwise have to devote to separate charging cables. This feature puts them well ahead of other credit-card-style power banks that lack such a convenience.

The TravelCard Chargers are totally straightforward to use: You charge them via the built-in USB-A cable and then charge your device using the built-in output cable (either Lightning or USB-C, depending on which one you get). A helpful notification light on the side of the charger next to the power button turns yellow when the battery is low and turns blue when it’s fully charged. The TravelCard Chargers even look like credit cards—sporting a sleek, metallic exterior—and the built-in cables are easy to pop into and out of their slots.

The reverse of the TravelCard Charge, showing a shiny black back and a built-in cable at either end.

Flaws but not dealbreakers: The TravelCard Chargers’ 1,500 mAh capacity rating is the lowest of any model we’ve considered. Their charging and recharging rates are slow, too—power flows out and in at about 6 watts. That’s about a third of the charging speed that an iPhone X can handle, so the phone’s battery meter will tick up much more slowly. But we think what the TravelCard Chargers lack in power they make up for in portability, and these drawbacks are a small price to pay for the ability to fit a power bank and charging cable in your wallet.

  • Capacity rating: 1,500 mAh (5.4 Wh)
  • Weight: 1.7 ounces
  • Tested input: 5.8 watts (built-in USB-A cable)
  • Tested output: 7.1 watts (built-in Lightning cable) or 5.9 watts (built-in USB-C cable)

Fastest possible charge: Anker PowerCore 10000 PD Redux

The Anker PowerCore 10000 PD Redux, a top pick for best portable chargers and power banks for phones and tablets, with a textured black and grey body highlighted with bright blue logo and USB ports.

Why we love it: Even without the built-in cables we so prize in our other picks, the Anker PowerCore 10000 PD Redux is a great choice, as it makes up for its deficiencies with faster charging and more power. Its rated capacity is 10,000 mAh, enough to fully charge most smartphones three times over. In addition to a versatile (if slow-charging, at 12.3 watts) USB-A output port, this power bank has a USB-C Power Delivery (PD) port that carries up to 18.8 watts of power—enough to charge all of the latest phones, and to recharge itself, at top speed.

This Anker power bank is about the same size and shape as a bar of soap. At 6.8 ounces, it weighs a fraction of an ounce more than the PowerCore III Fusion 5K (and about an ounce more than the iPhone 12). Its sleek, jet-black exterior and softly rounded corners make it easy to hold or to slide into a pocket. Subtle grooves in the plastic act like the ridges of a fingerprint, giving the power bank an even grippier texture. And four little lights next to the power button tell you how much charge it has left.

Flaws but not dealbreakers: A major drawback of the Redux is its lack of built-in cables. We always prefer having built-in cables over supplying and transporting our own cables—which take up extra space, get tangled, and are easily misplaced—to charge our devices. And unlike our other picks, which can recharge via built-in cables or plugs, the Redux needs a separate cable (one is included) to power itself back up. But we have yet to find a power bank with built-in cables that’s as small and sleek as this power bank and also supports USB-C PD charging and recharging speeds. If you want the fastest possible charge in a small package—and can bear to carry around a separate charging cable or two—this is a great option.

  • Capacity rating: 10,000 mAh (36 Wh)
  • Weight: 6.8 ounces
  • Tested input: 18.8 watts (USB-C PD port)
  • Tested output: 18.8 watts (USB-C PD port) and 12.3 watts (USB-A port)

Doubles as a wall charger: Anker PowerCore III Fusion 5K

The white square Anker PowerCore III Fusion 5K, a top pick for best portable chargers and power banks for phones and tablets, has ports highlighted in bright blue.

Why we love it: The Anker PowerCore III Fusion 5K is the best power bank we’ve found that’s also a good wall charger. Rather than having a wall charger that you leave at home and a separate power bank that you carry, you can rely on a single gadget that does double duty. It’s easy to use: Flip open the AC plug and stick it in a wall outlet to charge it, wait for the four little battery-status lights on the front to light up, and then take it with you for hours of portable power. And you don’t have to worry if your power bank dies while you’re out and about, because you can charge it on any wall outlet (or, with a separate cable, any USB-C port).

The Fusion 5K is a relatively small portable charger—about the size of a standard tape measure—and you can easily stow it in an accessories pouch or a roomy pocket. Its rated capacity (5,000 mAh, enough for nearly two full iPhone 12 charges) is more than three times that of the TravelCards. Each of its two USB-A output ports can send plenty of power to your devices, charging them faster than any other USB-A ports we tested: We measured 13.5 watts when it was plugged into a wall outlet and 12.5 watts when unplugged, so either way it can charge your phone a lot faster than Apple’s standard 5-watt charging brick. You can recharge the Fusion 5K via the AC input plug (which sends 10.9 watts of power to the unit from a wall outlet, according to the test we ran with a Kill A Watt Electricity Usage Monitor) or the 18-watt USB-C PD input port, which is convenient if you want to recharge it from a laptop or some other USB-C power source. Given this model’s rated capacity, that means it should take 1.7 hours to charge itself over AC or just an hour over USB-C PD, according to our tests.

Flaws but not dealbreakers: A big drawback of the Fusion 5K is that it’s less portable than the Redux—its chunky, squarish shape makes it harder to slip into a pocket—and its lack of built-in cables requires you to pack an extra cable or two to charge your devices. As far as two-in-one power banks go, though, it’s still fairly compact.

  • Capacity rating: 5,000 mAh (18 Wh)
  • Weight: 6.4 ounces
  • Tested input: 10.9 watts (built-in AC plug) and 18 watts (USB-C PD port)
  • Tested output: 13.5 watts (USB-A port when plugged in) and 12.5 watts (USB-A port when unplugged); 18 watts (USB-C PD port)

What to look forward to

The competition

The Anker PowerCore+ 10000 fits easily in a pocket—it’s the same width as an iPhone SE, about twice as thick, and just a few millimeters taller. And like the Redux, it has a hefty 10,000 mAh capacity rating. But its recharge speed is low compared with that of other models we tested (just 12 watts), and it offers only USB-C output, not USB-C PD. We also think its rough texture and less-ergonomic shape (flat on one side, rounded on the other) make it a weak contender.

The Anker PowerCore Fusion 5000 used to be our favorite two-in-one charger until the Anker PowerCore III Fusion 5K bested it. The newer model’s USB-C PD port offers faster charging and recharging speeds, leaving the Fusion 5000’s dual USB-A output ports and Micro-USB input port in the dust.

Like the PowerCore III Fusion 5K, the Anker PowerCore Fusion Power Delivery has a fold-up AC plug as well as a USB-A phone power bank port and a USB-C PD input/output port. However, its PD port is rated for 30 watts, which allows it to charge laptops such as a 13-inch MacBook Pro—something that none of the other two-in-one models we tested can do. Even so, we think its usual price tag of $80 (double the cost of the Fusion 5K at this writing) is too steep for its 5,000 mAh capacity.

The Aukey PB-Y33 and Aukey PB-N73S both have twice as many USB-A ports as the Redux, and they offer Micro-USB input in addition to USB-C PD. But they’re a bit heavier (7.6 and 7.9 ounces, respectively) than the 6.8-ounce Redux. Also, when we plugged them into the Total Phase USB Power Delivery Analyzer, they both produced connection errors, which doesn’t bode well for fast charging. We dismissed several other Aukey models without testing for this reason, even though they otherwise met our baseline criteria for testing.

Lightweight (3.1 ounces) and small enough to fit in a pants pocket, the Flux Charger and Flux Lite both have a Micro-USB input port, a USB-A output port, and built-in USB-C and Lightning cables. The only difference between the two, as far as we can tell, is that the Flux Charger comes in either black or white color schemes and the Lite comes in pastel blue, pink, or lavender. However, the cables are nearly impossible to get back into their slots after charging—in contrast to those on the TravelCard Charger models, which are velvety smooth to slide in and out—and the materials seem flimsier.

The Flux Charger Plus has a higher capacity (10,000 mAh) than the Flux Charger and Flux Lite (both are rated for 4,000 mAh), and in addition to built-in Lightning and USB-C cables it offers two USB-A output ports and a Micro-USB input port. But it isn’t as portable as its smaller brethren, and its built-in cables are similarly sticky.

We were going to swap in the HyperJuice 18W 10000mAh Battery Pack to replace the Jackery Bolt as our everyday-carry pick, but it was sold out at the time we published this guide, and the company told us it had no plans to restock that model. We may consider the 15,000 mAh version—which, like its smaller sibling, has built-in USB-C and Lightning cables, a USB-C input port, pleasantly round edges, and a dimpled texture for easy gripping—in our next round of testing, although it’s heavier and a lot pricier than our current picks.

The intelliArmor Scout Max is a jack of all trades, master of none. It has a built-in AC plug and Micro-USB port to charge itself, and its built-in Lightning, Micro-USB, and USB-C cables can charge pretty much any handheld device. But unsheathing the cables and plug is trickier here than on our picks, and its 10,000 mAh capacity is no better than that of the Redux. Plus, we couldn’t find any warranty information on the company’s site and can’t vouch for its customer support.

The Jackery 6700mAh Portable Charger with Dual USB Wall Charger (discontinued) had both USB-C and USB-A output, but it measured about a half-inch wider than the Fusion 5K. It also offered only AC input, whereas the Fusion 5K has a USB-C PD input port in addition to AC input.

The Jackery Bolt was our favorite everyday-carry power bank for four years, until the company discontinued it in 2020. We’ll miss it dearly, and we are on the lookout for a worthy replacement.

Although the Mophie Powerstation Hub has a bit more capacity (6,000 mAh) than the Fusion 5K and adds Qi wireless charging, we don’t think those features justify the usual $100 price tag. Plus, it has a more angular shape that’s not as comfortable to hold or easy to slip into a pocket.

The Mophie Powerstation Plus Mini has an adapter that lets you turn the built-in Micro-USB cable into a built-in Lightning cable, which is a nice idea, but sliding it on and off is not super smooth. The adapter also seems likely to vanish since it’s not tethered to anything. And without that adapter, the power bank is nearly worthless: You lose the Lightning-output function altogether, and the Micro-USB cable still works but doesn’t stay firmly in its slot.

The RAVPower PD Pioneer RP-PB186 is nearly identical to the Redux except it has rough ridges at each of its seams that make it less comfortable to hold. But if you can get it for significantly less money than the Anker model, it would be a great alternative.

The RAVPower PD Pioneer RP-PB172 has more capacity (20,000 mAh) than any of our picks, and it offers a wide range of input options, including Lightning, Micro-USB, and USB-C PD. However, only the last option recharges the power bank at top speed, and aside from the PD port this model has only one other (USB-A) output port. If you want the ability to charge a phone or tablet many times over, we think you’re better off spending a little more for one of our high-capacity power bank picks—all of which offer plenty of output options, support data transfer as well as charging, and provide enough power to charge most laptops.

The Real Graphene G-Lite is the only power bank we’ve tested that’s made with graphene, a material that allows electronics manufacturers to pack a lot of power into a small package. Case in point: It’s barely heavier than the Redux at 6.9 ounces, yet it has almost double the citibank credit card phone number australia (we measured 18.5 watts from its USB-A port and 30 watts from its USB-C PD port) and input (32 watts) capabilities. And considering that it comes with a 60 W PD wall charger and a USB-C cable—we estimate a $20 value, though we haven’t tested either of those accessories—the price is on a par with that of the Redux. However, most phones and tablets can take advantage of charging rates only up to 18 watts anyway, and the G-Lite’s 5,000 mAh capacity is half that of the Redux. Plus, we noticed that the G-Lite’s textured finish (while cool-looking and grippy) collected dust and crumbs in its crevices. If you’re looking for more power than the picks in this guide supply, we think you’d be better off with one of our favorite power banks for laptops—which weigh more but provide more power, offer more port options, and have much higher capacity ratings—instead of this model.

The Tronsmart Trim 10000mAh USB-C Power Bank has the same capacity rating (10,000 mAh) as the Redux and adds a Micro-USB input port. However, we don’t think an extra (and slower-charging) input option offers a huge benefit to most people. Also, judging by our past experience with both brands, we think the Anker USB-C cable that comes with the Redux is a better value than Tronsmart’s Micro-USB cable.

The Xcentz 5,000 mAh and 10,000 mAh Portable Chargers are most comparable to the Redux in that they weigh less than half a pound each and offer a single USB-A and USB-C PD port apiece. But the rounded edges and narrower shape of the Redux make it more comfortable to hold or pocket, and they give it a slightly more pleasing aesthetic.

The ZMI PowerPack Ambi 10K Dual USB-C Power Bank has the same capacity rating as the Redux, as well as an extra fast-charging USB-C PD port. However, it has no USB-A output ports, and its combined output rating (20 W) is lower than what we measured from the Redux (18.8 W and 12.3 W, or over 30 W total). Plus, the ZMI model is bigger and heavier.

We dismissed the Anker PowerCore III Sense 10K without testing it because its listed weight (7.5 ounces) was heavier than that of the Redux, and at the time of our research it cost $10 more. But if the price drops significantly, and you don’t mind the extra weight, it seems like a fine alternative to the Redux. We also opted not to test the Zendure SuperMini since it costs $70, at this writing, for the same capacity (10,000 mAh) you get from the Redux. However, if it goes on sale, you may want to grab it—this model is very lightweight at 6.4 ounces, and it comes from the company that makes one of our favorite high-capacity power banks.

About your guide

Sarah Witman

Sarah Witman has researched, tested, and reviewed all manner of products—from massage chairs and mousetraps to pencils and power banks—since joining Wirecutter in 2017. Before that, she worked as a science writer and fact checker for numerous publications, and she studied journalism at the University of Wisconsin. In her spare time, she eats as much cheese as her body will tolerate.

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phone power bank

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  1. I have the thing where it says claim it and keep it in PayPal like you did and I don’t want to mess it up so what do I do

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