Sharp FS8009 (marketed as Sharp Z3) sudden excessive battery drain

[Android Central Question]

I bought this one in November 2017, and the battery drain was very good around 0.3%/hour (during nighttime standby). Installing all kinds of apps and games, messengers, nothing affected the great battery drain.

In March 2018, things turned the wrong turn. I've got a sudden spike in battery drain, ranging from 0.8% - 2+%/hour (during nighttime standby).

Even in powered off mode, the drain is about 1%/hour, 3% in 3 hours.

The apps stay the same, but I couldn't control the Android update. It's still on Android 7.0.

The drain was monitored with GSAM the whole time, on WiFi only, mobile data deactivated, Bluetooth off.

Local Sharp service representative doesn't respond to it, just deflecting that such high drain rate is normal, ignoring the fact that it had been 0.3%/hour. Several e-mails sent directly to Sharp Japan also never got any response.

 

[belodion]

If, as you say, the battery loses charge, or is indicated as doing so, with the phone powered off, there is something wrong somewhere.

 

[hstpctech]

Thank you for the quick reply. At least now I'm certain the phone has a real problem.

Before March 2018, putting the phone on airplane mode only drain it 0.1%/h. But now it's all the same, whether in airplane mode, turned off, or WiFi only, the drain is between 0.8% - 2+%/h. And that was with all apps installed, games and otherwise.

My concern is that I've lost all the GSAM screenshots I took as proof, and Sharp is trying their best to avoid the warranty coverage. I've sent it for repair once, but they didn't fix anything nor replace anything. They just did a factory reset, which I've done several times already on my own.

Let it be a warning for others who planned to get one of these, keep your money and stay away from the ugly after-sales service.