Does any charging analyser work under 4.x

I’ve always charged my XA2 from USB and it’s mostly not working. The charging sign shows but the battery % doesn’t go up. Sometimes it says the voltage is too low. Sometimes the charge even goes down, as if my XA2 is charging my laptop!

I’m trying to diagnose the problem but can’t find a charging analyser that works under 4.x. Something to do with stateFS apparently.

Edit: The problem has resolved itself, apparently from battery level falling below 20%. I think this was to do with Sailfish’s or my XA2’s own calibration rather than the Battery Saver function.