There are situations when the gadget is discharged at the most inopportune moment, and there is no way to charge it due to the lack of an outlet nearby. In such a case, a Power Bank (external battery) is used, which can easily help restore charge on a smartphone or other device with the ability to charge via USB.

What is a Power Bank?

Power Bank is a popular device that is convenient to take with you on trips, travels, as well as to work or school. Due to the large number of models, characteristics, external solutions and dimensions, the task of choosing the right device becomes difficult. Therefore, before buying it, it is recommended to independently understand the main selection criteria. This will help you avoid mistakes and choose an external battery that is ideal for your smartphone or other gadget.

power bank

Power Bank, also known as an external or portable battery, is a battery that can charge gadgets such as a tablet, smartphone, e-book, camera and other devices that can be charged via a USB cable. The battery itself also requires periodic charging, which is carried out through an outlet or computer.

Such a device is capable of storing stored energy for a long time. That is why it is very convenient when traveling, in places where there is no constant access to power supply.

Inside the external battery there are several storage elements connected to the controller board. The board has one or more connectors for charging gadgets.

For maximum compatibility with as many devices as possible, the Power Bank has a universal USB 2.0 connector.

Battery capacities

When choosing a device, special attention should be paid to its capacity. It is measured in units such as milliamp-hour (mAh). It is these values ​​that will help determine which gadgets can charge a particular external battery. The larger the capacity of the Power Bank, the longer it will be able to charge portable devices.

To choose the right device, first of all, it is necessary to determine how many full recharges it should last. Then the resulting figure should be multiplied by the battery capacity of the gadget and by a factor of 1.5.

You should not blindly trust the tables that indicate the battery capacity: an external battery with a capacity of 10000 mAh is not capable of charging a smartphone with a capacity of 3100 mAh 3 times. In the best case, charging is enough for 2.5 times, and in most cases – for 2 times.

This is because the Power Bank voltage is 3.7 V and, depending on the current charge of the device, may fluctuate up or down. Therefore, the voltage first rises to 5A to comply with USB standards, then it flows through the cable into the device being charged, after which the charge controller on the gadget reduces the voltage to the required values ​​​​for full charging of its battery. Due to double conversion, 20-30% is lost.

Power bank in hand

Current strength

The second important criterion when choosing an external battery is the current strength, since it determines how quickly the gadget will charge (the higher it is, the faster the charging occurs). To avoid any damage to the device being charged, you need to find out what current strength will be optimal for charging its battery. This information can be found by reading the label of the “native” charger that comes with the gadget.

Power Bank Output Current Recommendations:

  • Devices up to 1A are very rare and are only suitable for recharging simple phones (for smartphones, it is too weak).
  • 1-1.5A – this indicator is ideal for recharging smartphones. At lower current rates, the charging process will be significantly delayed, and if you also use a smartphone with a capacitive battery, then the charging indicator can stand in one place. It is not recommended to connect an external charger with a current of 2A to the device without specifying in advance how appropriate this would be.
  • 2-4A is a suitable option for tablets. Such indicators allow you to quickly charge your tablet computer.

There are smartphones with a built-in controller, which, when a current strength is higher than necessary, optimizes it to acceptable levels. These are the safety measures provided by the manufacturer.

In the electronics market, there are also external batteries with express charging function. When this device is in operation, the voltage rises, and the current decreases, which allows you to charge your smartphone only half (50-60%) within 30-40 minutes.

Functional features

The functionality of each of the external devices for recharging gadgets is individual. The richer its functionality, the more practical the external battery. These criteria include:

  • Availability of exits. For the convenience of using the device, the current strength is affixed near each output. This is necessary in order to make it easier to determine which socket can be connected to a particular gadget.
  • Availability of adapters and cables. Equipping an external battery with additional cords for recharging will not be superfluous. This is due to the fact that the universal connector is not suitable for old-style mobile devices, and additional cables will do the job perfectly.
  • Digital charge level indicator. A very useful solution that allows you to accurately navigate the amount of remaining energy. When choosing a portable battery as an additional one for recharging your phone, this function should be considered immediately after the main ones.
  • Additional USB ports. Their presence will come in handy if you need to charge several devices at the same time.
  • LED flashlight. It can be useful in the dark, to illuminate the socket to which the external battery will be connected.
  • The presence of a solar panel. In addition to recharging the Power Bank from the network or other sources, the presence of solar power will allow you to accumulate additional energy in the device from sunlight. It should be mentioned that one should not expect a large accumulation of energy from such a panel.

Solar Power Bank


When choosing a portable charger, you need to pay special attention to the indicators of the incoming current for the gadget and choose a model so that its output voltage matches it.

You can find out information about what input voltage is required to fully charge the device by examining either the data on the network charger that came with the gadget, or in the instructions for it. For most gadgets such as tablets, smartphones, action cameras, navigators, the most common DC voltage will be 5V (5V DC), which corresponds to USB parameters.

Typically, the current requirements are not so stringent. This is due to the fact that when charging a device with a lower current requirement than an external battery, the controller is activated, which equalizes the current to optimal performance.

Charging features

The simplest external batteries have one USB output, while the more advanced ones have two, often with different output currents. But there is one caveat: when charging two smartphones at the same time, a minimum current will be supplied.

The board built into the Power Bank also has certain functions that allow not only to simplify the use of a portable device, but also to maximize its service life by properly organizing the charging process. It:

  • Automatic power off. A convenient option for people who do not have time to monitor the progress of charging. They can leave their gadget connected to a portable device for a long time without worrying about its condition.
  • Load shedding. This is the same option, only located on the other end of the portable battery. In this case, the automation monitors the control of the charging of the battery itself and turns it off as soon as the device restores its potential.

When choosing a Power Bank, you should check with the consultant how the external device itself will be recharged. There are such batteries that are charged not only from a power outlet, but also through a computer or phone port via micro-USB, have the already mentioned power source in the form of a solar battery, or are charged from the cigarette lighter in a car.

Other selection criteria

Other criteria for choosing a Power Bank device are:

  • Weight and dimensions. In this case, the formula is simple: the weight directly depends on the capacity of the external battery (the larger the capacity, the greater the mass). This indicator is also affected by the type of battery used: a lithium-ion (Li-ion) battery will have more mass than a lithium-polymer (Li-pol) with a similar capacity. It is also impossible to ignore the main material from which the case is made. For example, an aluminum case will be much heavier than a plastic one.
  • Device design. Thanks to a large selection of models and extraordinary design solutions from manufacturers, a potential buyer has a wide selection of external chargers. There are external batteries in the form of a milk carton, cartoon characters, animals, car models.

Power Bank designer

  • Manufacturer. Since the Power Bank is considered a high-tech device that has a number of protective systems that are necessary to ensure the performance of the gadget, it must effectively neutralize all possible threats that can harm the gadget while charging. It follows from this that you should not buy a device from an unknown manufacturer, as there is a risk of buying a low-quality external battery. Subsequently, this can cause a breakdown or failure of the battery of the rechargeable gadget. It is recommended to buy products only from trusted brands and be wary of too low prices.
  • Body and material. The battery case can be made of plastic, metal or polycarbonate. The listed materials do not differ much in terms of practicality, the only caveat is the difference in weight. So, the metal case is heavier than the rest. If the Power Bank is purchased for use in extreme conditions, it is recommended to choose an external battery made of impact-resistant materials (such as aluminum), and to select and use rubberized cases. In addition, it is worth paying attention to the presence of reinforcing elements on the body.

Top 5 Most Popular Power Bank Models

Today, among the variety of external batteries, it is quite difficult to make the right choice. To facilitate this task, you can use the rating of popular models, which is based on customer reviews.

Xiaomi Mi Power Bank 2 10000

The Xiaomi manufacturer is, first of all, the ratio of affordable price and quality. This model is no exception: the device contains all the necessary features that will help when the gadget is discharged.

Main characteristics:

  • battery: Li-Polymer;
  • capacity: 10000 mAh;
  • device weight: 228 g;
  • input current: 2A;
  • maximum output current: 2.4A;
  • price: 20$.

Xiaomi Mi Power Bank 2 10000

The advantages of the model include the following:

  • the possibility of express charging;
  • streamlined shapes combined with a metal case;
  • the presence of USB and micro-USB cords;
  • protection against short circuit, overheating and overload.

Also, the advantages of this model should be considered a rich color range, which will not leave indifferent lovers of bright colors.

Xiaomi Mi Power Bank 20000 mAh

This is a Power Bank model with a fairly large capacity. The battery is perfect for people who need a large supply of energy. The body of the device is made of plastic. Using Qualcomm Quick Charge 2.0, the portable device charges in a short time, has a charging indicator and protection against overheating.

Xiaomi Mi Power Bank 20000 mAh

The main characteristics of the device:

  • battery capacity: 20000 mAh;
  • battery type: Li-ion;
  • fast charging function;
  • 2 USB connectors;
  • output current: 2A;
  • maximum output current: 2.1A;
  • weight: 338g;
  • price: 50$.

The model is capable of charging two smartphones at the same time.

Power Bank ASUS ZenPower 10050 mAh ABTU005

An external battery from manufacturer Asus is a worthy competitor for devices with a medium capacity. The body of the device is made of metal and has various color variations.

Power Bank ASUS ZenPower 10050 mAh ABTU005

Main characteristics:

  • battery capacity: 10050 mAh;
  • battery type: LI-ion;
  • input current: 2A:
  • maximum output current: 2.4A;
  • weight: 215g;
  • price: 30$.

The manufacturer also took care of safety by building protection against reboot and short circuit into the device.

Canyon CNE-CPB156

It is considered the most ergonomic Power Bank device.

Canyon CNE-CPB156
The main characteristics of the external device:

  • battery capacity: 15600 mAh;
  • battery type: Li-Polymer;
  • input current: 2A;
  • output current: 1 and 2A;
  • the presence of two USB-connectors;
  • weight: 440g;
  • price: 35$.

This model has an impressive volume, which can provide several full charges to a smartphone or simultaneous charging of two devices at once. It has a light indication and a plastic case.

Power Bank Pisen 10000

The compact size and shape of this power bank is very convenient for everyday use. Also, among the advantages of this device, it should be noted the optimal capacity, the ability to charge a tablet computer and a smartphone at the same time, the presence of charging indicators.

Power Bank Pisen 10000

As for the main characteristics, they are as follows:

  • battery capacity: 10000 mAh;
  • battery type: Li-ion 18650;
  • input current: 2A;
  • maximum output current 1-2A;
  • one USB connector;
  • device weight: 270g;
  • price: $13-15.

To prolong the life of the Power Bank, you should not allow it to completely discharge. You need to charge it at such a current strength, which is indicated in the characteristics. It is also not advisable to charge it at too high or low temperatures.

Which Power Bank to buy in 2018? Video review

Watch a video reviewing the most popular latest portable battery models to help you make your final choice:

Power Bank is a compact external battery that provides charging of any gadget even in the absence of an outlet and mains. There are many devices of this kind with different characteristics on the electronics market. You can choose either the simplest Power Bank with the ability to charge your smartphone 1-2 times, or a model that allows you to charge several mobile devices at the same time.