Is it normal for my battery to charge like this?

[Android Central Question]

I have an Asus Zenfone 2; surprisingly it supports Asus BoostMaster (and its in par with Qualcomm Quick Charge 2.0)

I was using ampere while I was charging and noticed that when my battery is on 50% and charging it would blast up to 1020mA

But when its around 80% it would go down to 240mA, I am not sure if that is normal

My second question is, on LineageOS (on my phone), I will plug in my phone and first (on the lockscreen) it would show Charging Slowly and then a few seconds later, It would show Charging Rapidly and then it will show only Charging.

I have done factory resets and such, I replaced my own Charging Port motherboard, but to no avail.

I hope these two questions can be answered.

Thanks in advance,
Nabil

 

[Tim1954]

Most devices these days ha sophisticated regulatory circuits that control charging rates. These monitor temperature, current flow and other things and regulate the charging rate accordingly.
If your device doesn't get hot, or take ridiculous amount of time to change, it's probably doing the job correctly.

 

[Rukbat]

It takes a second or two for the phone to measure the current charge state, then to kick into high current charge if the battery is under 80% - that's why it starts with "Charging Slowly".

As for the step down, that's normal. Quick charging usually works up to 50%, then steps down to normal charging. But a 1020 ma charge on a 3000mAh battery isn't going to harm the battery even if it doesn't drop until the battery is 98% charged (which is about when the phone first reports 100% - which is why you should leave it on the charger for about 30 minutes after it first says 100% - to get a full charge*). Lithium batteries can accept up to 1C without any problem, which for your 3000mAh battery is 3000ma. But 1020mA is conservative, so that if the charging circuit is so out of spec that it charges at twice the design rate (and that would be a manufacturing defect covered under warranty), it's still under 3000mA.

Your phone is working just fine. Don't try to fix it - it's not broken.

*Due to the way we measure battery charge, measuring the terminal voltage of the battery, the indicated charge is always going to be higher than the actual state if the charger is connected. (In order to force current from the charger to the battery, the charging voltage has to be higher than the battery voltage [electricity, like water, flows downhill]. That higher voltage indicates a higher charge than the battery actually has.)

The only other option is to measure the state of the chemicals in the battery, and something to do that would probably cost more than a Note 8 just for the stuff needed to measure the charge of the battery. (And it wouldn't fit in a pocket.)