I have a Xiaomi Redmi Note 4 S625 global variant (4/64GB). A day or so ago, I noticed a quick battery drain (from 100% to 24% after a whole night idle and 2-3 hours of heavy use the next day) and from there, it was dropping a percent every 2nd-3rd minute. It never happened before as it's a 4000mAh battery and usually lasts around 2 days on normal use.

I'm new to the smartphone world and I was reading online about the usual causes of battery drain including background apps consuming it and overcharging issues damaging the battery. I got worried as last night it was indeed left plugged in for like 2-3 hours maybe after a full charge. So either the battery is damaged due to overcharging, or it's some software issue.

Now what I noticed is the CPU usage is maxed with no app running in the background. I don't know if CPU-Z's usage info is accurate, but it's 100% when the battery is like 15% or lower and 40-50% when the battery is 20% or above. Maybe there's some background process or maybe it's normal, I don't know. I'm pretty clueless at this point. Here's a screenshot of CPU-Z:

Really appreciate it if anyone helped me with this one. Thanks.


1 Answer 1


The reason for battery drain is mostly app. Either because of the poor development skills of the developer or because the app is doing something it shouldn't. Well, if you overcharged it for 2 hours after the full charge, you don't have to worry. No battery is that bad to die like that. I mostly left my phone on the charger overnight and I don't have any problems, yet :).

Is the screenshot from CPU-Z taken just when it loaded or a few seconds later? Because in every phone, when it just loads, it shows high CPU usage.

However, you should see if there is any shady app like fancy keyboards or fancy galleries. Try deleting them and see what is happening or apps installed out of the Play Store.

You can use an app called Wakelock Detector to see what is causing the problem. You can find some help about it on XDA.

  • Thanks. The picture is taken after a few seconds. I'm aware that it goes high as soon as you launch CPU-Z but the picture is taken after sometime and the usage it show stays between 80s and 100s. I have Gboard and default gallery and will stay with them as they do the job.
    – John Doe
    Aug 18, 2017 at 18:51
  • Now after charging to 90% and restarting phone, usage was between 15-20% and it has risen to 40-50% after sometime at 84% battery. Will try factory resetting it to see if it's caused by an app.
    – John Doe
    Aug 18, 2017 at 18:53

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