iPhone 15 Pro Battery drop after restarting

[bp1000]

My battery % was just reading 17%, decided to restart my phone and this fell to 13% in the space of 1 min.

Any ideas why this happens?

 

[JPack]

Usually poor battery calibration or defective cells.

 

[LouisPiper]

It also uses battery to restart. That plus recalibration makes sense.

 

[antiprotest]

4% is a bit much for restarting and "recalibration." Something is wrong if it's that much every time you restart.

 

[LouisPiper]

4% is a bit much for restarting and "recalibration." Something is wrong if it's that much every time you restart.

I would be doubtful it does it *every* time a restart occurs.

 

[bp1000]

I suspect it might be calibration given it is a new battery.

I currently have it limited to 80% charge and this morning it stayed at 80% for nearly an hour of screen on time.

I'll run it down a few more times and try restarting to see if this behaviour continues.

 

[coso]

It's normal, my 13P did the same. It's a combination of calibration, power usage during reboot (not little, phone does a lot of stuff) and also how soon you did recharge. Because iPhones "lie" to you a little just after you detach the charger, it keeps the percentage 3-4% higher than it is to give you the impression that the battery is lasting good. If you restart you lose this little lie and it recalibrates again to the real battery percentage. It can also happen the other way around, I rebooted a couple days ago and "earned" 4% battery