How to choose an external battery (power bank)?

An external battery (power bank) has become an almost indispensable gadget for everyone who uses their smart devices every day. We know how fast the battery drains and it is always good to have a backup power supply. Power Bank is a great solution.

There are a lot of these devices that save the situation, various manufacturers, quality, capacity, colors, shapes… Which to choose?

First of all, let's clarify what mAh means:

mAh - milli-ampere hours, ie battery capacity. In order not to introduce other terms unknown to some, it is enough to know that more mAh means longer battery life.

This data is very important, but the most important data are "Real capacity" and "Conversion rate".

"Real Capacity" is, as you assume, the real capacity of the battery, and this is achieved using the formula:

External battery capacity * conversion rate * phone battery health/phone capacity

Piece by piece:

1. External battery capacity - the capacity you see written on an external battery (eg 12000 mAh)
2. Conversion rate - you can see this information somewhere on the packaging or in the battery documentation (quality external batteries have over 90% "Conversion rate")
3. Battery health - the battery loses "health" over time, and therefore you notice that it lasts shorter over time. You can view this information with various phone applications. Basically, if the device is not old, you can enter a value of 0.9
4. Phone capacity - battery capacity in the phone (eg 1500 mAh)

When we insert specific data into the formula, we get:  12000 x 0.9 x 0.9 / 1500 = 6.48

So, with an external 12000 mAh battery that has a "Conversion rate" of 90%, we can charge the phone's battery, which is in good condition, with a capacity of 1500 mAh, more than 6 times.

So, we do not calculate classically: 12000/1500 = 8 charges, but we use this formula where we have included other very important parameters.

Ok, we know that now you need to look at other information when buying an external battery. In addition, we know that better quality, stronger, longer-lasting batteries cost more. I bought mine on Aliexpress at a discount at a relatively low price.

I opted for the original Xiaomi Mi external 5,000 mAh battery due to its excellent build quality, high Conversion Rate of 93%, various overheat protection, short circuit, high and low temperatures, overcharging and discharging… It all cost me 15 euros! In local shops, I saw that weaker batteries, of poorer quality, cost so much.

Xiaomi Mi external battery comes in a compact package with an additional "micro USB" cable for charging smart devices, and the battery itself is in a very high-quality case that has protection against high temperatures. It is very thin, elegant, and of minimal design with the "Mi" embossed sign.

Also, the battery has light indicators of charge, as well as an on/off button. It is compatible with all devices that can be charged via a USB port.

If you want someone else, cheaper, weaker, stronger ... you can watch them whole arsenal HERE.

And on this link, you can find out how to buy a product from that site -  https://do-you-know-tech.blogspot.com/2014/09/how-to-buy-from-chinese-sites.html