How to check battery capacity?

Question

Charger

We bought a xiaomi power supply for 10.000mAh, but there is a feeling that it has stopped charging.
How can I check the capacity and does it work at all?

Answer 1

If at home and without special devices, then you can try to charge the power-bank under study completely and charge a completely discharged phone from it (several times or several phones). Add up the phone battery capacity and divide by 0.70 (roughly). The resulting value is the approximate capacity of your power-bank (declared, adjusted for efficiency).
Topic about power-bank capacity - https://geektimes.ru/company/madrobots/blog/246786/
Other methods require at least a multimeter, soldering iron, load resistors, etc.
UPD. Adjusted the efficiency factor.

Answer 2

Firstly, make sure visually (that there is a battery and not two nuts and a battery), secondly, by weight, and thirdly, there are special devices for measuring capacitance.