[Galaxy S 4 Mini Q&A, Help & Troubleshooting] H10N3:
Battery drain

Hi all,

I have been struggling with battery drain issues ever since I got my phone.

I was able to finally resolve the issue for me yesterday, and I want to share my findings hoping that others will benefit.

I am running [ROM][Unofficial][CM-12.0 - 27 APR][CM-12.1 - 27 APR] S4 Mini duos GT-I9192 : cm-12-20150425-UNOFFICIAL-serranodsdd.zip

My battery used to last around or less than 12 hours, normal use. I would have sync on and then turn it off to see if there is any difference and it made none. When the coverage is bad, the sync drains more battery obviously.

I move a lot so I get a varying degree of network coverage and the better the coverage the better the battery life. I would stay in places with full coverage with sync off and still get battery drain.

I thought that WiFi was the culprit and I thought it was the GPS that was the culprit and I looked at individual apps and I was suspecting faulty hardware and faulty battery and faulty software.

I love to flash custom ROMs onto my phone and I have tried quite a few ROMs, from the stock to the "Russian Stock" to the unofficial 4.4.2 and the RR remix ROM and I can safely say that the choice of ROM made no difference whatsoever for my battery drain.

I used the have the issue when I would remove the battery and reinsert it and get a huge drop in percentage left. Drops in reported percentage left would be around 20%. Other times the phone would report 1-2% battery left and shut down, so I would remove the battery and 10 minutes later reinsert the battery and have 15% left, just for the percentage to drop quickly back to 0% and the phone would die.

The problem was with the battery reporting being off, way off. It was off when I unpacked the phone when it was brand new and it was off 3 days until the problem seemed to solve its self as if by magic, but was it really magic?

The battery drain issue was not so much a drain issue, as it was a faulty reporting issue. The phone had faulty battery values from the start somehow and that is where my attention needed to be focused.

What I did to solve the battery drain issue:

I was keeping up the new releases of the above mentioned ROM, which is great by the way, thanks to the devs. So I had fresh installs and did a lot of clean wiping.

2 apps that I used to solve the drain issue are: Batterycalibration and 3C Toolbox

I would charge the battery to 100% and wait for the "current charge" to reach maximum value (this requires a bit of monitoring because sometimes the app reports 100% but not maximum mV) then Calibrate in BatteryCalibration.

Let the phone discharge and die, remove battery for a few minutes (10 min is fine), reinsert battery and boot, and repeat until the phone wont boot anymore.

Charge to 100% and calibrate.

Install 3C Toolbox and get into the configuration wizard and let the app Estimate automatically.

repeat the above procedure.

Within 3 days of 3C Toolbox and BatteryCalibration working together my battery life started to average out and the battery would live longer.

As I write this my phone has been unplugged for 25 hours and I have 46% battery left. I used the screen for 1h 40min and there are no sudden drops in stats reporting. The GPS has been set to "Battery Saving" and the WiFi has been on the whole time.

Links:

3ctoolbox: https://play.google.com/store/apps/details?id=ccc71.at.free

Battery Calibration: https://play.google.com/store/apps/details?id=com.nema.batterycalibration

Hopefully this can help some poor soul out there to solve the dreaded battery drain issue on the GT-9192