how to know battery capacity?

[nianku]

I’ve had a 4200mah extended battery case from mpj since last Friday. It definitely feels like a quality product and my S6 won’t run out during one day of use now, but how can I make sure that the case is 4200mah?
Thanks.

 

[S6edge46220]

Only way I know of would be to tear it down and verify markings on the actual battery.

In other words, you take their word for it.

Posted via the Android Central App

 

[spark_spek]

I’ve had a 4200mah to use...

 

[Rukbat]

Actually the only way to know (the markings could be fake, the battery could be defective) is to fully charge it, then discharge it under controlled conditions and see if you get 4200mAh from it. I wouldn't do that more than once, though - it puts a LOT of stress on the battery. (Discharging to 0 is considered a destructive test - you do it to test the design, you don't expect to be able to use the battery that was tested. It may not hold a full charge any more and it will probably fail young.)