[Android Q&A, Help & Troubleshooting] Me_Zaid:
"Android OS" Process Taking Almost All The Battery Usage Percentage During Standby

Hello! I have a question regarding the behavior of an Android system. I've seen many people reporting not only high battery usage from the "Android OS" process, but abnormal drainage as well. So my question is - is it normal for the "Android OS" process to have the highest battery percentage (without abnormally draining it) IN STANDBY, in Android 6? I'm talking about a situation of "pure" standby - no running and no useless background apps.

I'm asking because... for instance, I have an Android 4.4.2 (KitKat) phone as well, and when it's on standby, well... something has to consume the battery, right?... Even if it lasts 15 days or so in standby. So KitKat reports the highest percentages to be occupied by "Mobile standby" and "Phone idle"... it's a 50/50. No other process (including "Android OS") appears in the calculation.

I can assume that Android 6 has different algorithms for calculating battery usage than Android 4. Those stats seem to be more shallow and lossy at the 6. I'm saying it because I rarely see any app appearing in those stats, even after heavy usage.

Also, I made a clear distinction between abnormal drainage and a high battery usage percentage. (As long as a system is on, some process has to consume battery in order to make it "ready to go" and be able to keep it on standby.) My Android 6 system is not abnormally drained by that process... it's just that it has the highest percentage, followed by "Cell standby" and "Device idle". Is it normal? For the record, the Android 6 device I'm talking about is an Asus Zenfone Zoom (ZX551ML).

Many people reported high battery usage by "Android OS" and inexplicable drainage (Some couldn't get it to stay even a day in standby) as well from the mighty Zenfone Zoom, but during testing, my device turned out to be able to resist almost a week (if not more if I used it less) in a "pure" standby state (all the major functions were turned off - Wi-Fi, cell reception, NFC, touch gesture support, automatic brightness; also, I had no running apps). Of course, "Android OS" was reported to be the most consuming process in terms of battery power. I can assume it's a normal behavior and not an issue. Or... is it?

Even when I used it a bit, with some apps on, it was still a battery beast in standby. I attached some links to screenshots in the post, to make it more accurate and show what the approximate proportions between battery usages are.

[No, I didn't attach any links. They won't let me post links yet from spam control reasons... And not even attach damn images!]

I am making a call to you because I've seen very poor assistance on the official Asus support forums - very mediocre and unprofessional assistants with an overall poor technical sense and perception. You have an example of that particular issue (the abnormal drainage) here - [Ah, they don't let me post links yet! I'm a new member.]

I just want to shed light on whether such high battery usage from "Android OS" is normal or not (in a standby scenario, of course). Heavy draining in standby is clearly abnormal [as what the guy from that forum (the missing link) experiences].

I have to say (not that you wouldn't know it already!) that this combination of an Intel processor, a device of such huge proportions as the Zenfone Zoom and a 3000 mAh battery is not going to be a happy combination in terms of battery autonomy DURING USE. When I use it, I lose battery bars pretty quickly (It's expected from a such configuration; the Intel machinery is not very conservative in terms of power), but in standby and with little use, it can be an autonomy beast!