How to choose an external battery for phone / smartphone?

Users who are at least somewhat interested in mobile devices must have heard of external batteries. The essence of the device is reflected in the name of the device – this is the battery with which you can charge the battery of another device. Power Bank, which is what the external battery is called in English, is usually a small device that fits easily in a bag (sometimes even in a pocket), and its capacity is often enough to charge a smartphone a couple of times. Today we would like to talk about exactly what you should pay attention to when buying Power Bank.

External battery capacity

Perhaps this is the first thing you should look at. First, decide what capacity you need. As an example, take a battery with a capacity of 5200 mAh (milliampere-hours). Let’s say that the smartphone’s battery capacity is 2500 mAh. This means that with the help of an external battery, you can charge the smartphone about 2 times (you need to include minor energy losses here). Accordingly, on the basis of this, you must decide whether you need such a capacity of Power Bank or not.

As for the maximum capacity, on sale you can find external batteries with a capacity of several tens of thousands of mAh! However, you should be aware that such a device has such dimensions that it barely fits in a women’s bag.

Another important point is the voltage at the output of the external battery. It may vary, and this, in turn, may result in external batteries having the same capacity but different voltage, in reality, will contain a slightly different amount of electricity. However, the difference should not be significant.


This important parameter affects primarily the charging speed of the gadget. For example, if you try to charge a smartphone with a battery with a current of 0.5A, it will charge one and a half to two times slower than with the same battery, but with a current of 1A.

The optimal current strength for tablets is 1.5-2A, otherwise it will charge very slowly.

There are batteries that support amperage from 3A and even higher, but 1A will be enough for a smartphone. Moreover, such a current strength favorably affects the battery operation of the device that you plan to charge.


An extremely important parameter. If you have a backpack or bag that you always carry with you, there probably is no reason to think about the dimensions of Power Bank. Another thing if you plan to keep an external battery in your pocket.

As a rule, the capacity of an external battery directly depends on the size: the smaller the case, the less capacity. Therefore, it is recommended to pay attention to both the battery capacity and its size.

Declared and actual capacity

Unfortunately, not all batteries show the declared capacity. For example, there are cases when, with the claimed capacity of 5000 mAh, the real capacity of the gadget barely reached 3000 mAh. What is the reason for this? There are two options: either the manufacturer company is deceiving, indicating inaccurate data, or the case is in the wrong storage and transportation.

What to do? Read reviews: among users there are many who do not mind checking the actual capacity of an external battery. Based on reviews, conclusions can be drawn..

Body material

Everything here is strictly for the amateur and, in fact, it makes no difference whether the body is made of plastic or metal. Another thing if you like tactile sensations. By the way, there are batteries on sale whose case is made of wood.

Extra bonuses

Bonuses include, for example, the presence of several USB ports. They are needed so that you can simultaneously charge several different devices. As a rule, small batteries both in capacity and in size are endowed with 1-2 USB ports, large ones – 8 and even more.

It is also worth paying attention to the indication of the charge-discharge of the battery – it can be LED, or in the form of a screen, which shows the battery discharge in percent.

Included with some external batteries you can find all kinds of adapters – quite a nice bonus.