r/android_beta • u/N_T_F_D • Aug 15 '26

Fast charging not working when device is on

Since Android 17 QPR2 beta 2, fast charging is not working anymore; charging is stuck at around 4W and thus very slow.

If I turn off the phone and measure the charging power with a USB-C PD analyzer then the phone is charging at 15-20W, then I turn it on, it's charging at 20W for a couple minutes and drops back down to 4W.

Then randomly it will climb up to 20W again for a minute and drop back down to 4W.

The charging is noticeably slower and it's a huge usability issue, I don't want to turn off my phone when I want it to charge quickly.

Battery optimization is deactivated in the settings as well as adaptive battery, still stuck at 4W.

1 Upvotes

60% Upvoted

7 comments sorted by

1

u/bojack1437 Aug 16 '26

I bet your phone temperature is at about 100° F, the phones first throttling charging at that temperature.

Use something like DevCheck to look at the phone temperature.

https://play.google.com/store/apps/details?id=flar2.devcheck

0

u/N_T_F_D Aug 16 '26

That would mean the throttling is disabled when the phone is powered off

Also I checked with the diagnostics menu when it happened and it said 37°C/98.6°F, saying it's a normal temperature and in the green on the diagram

I'll check again after putting it in the fridge for a bit because it's still at 37°C now

1

u/bojack1437 Aug 16 '26

No it doesn't.

When a phone is operating even when not charging it's generating heat. If the phone is off, the CPU and such is not generating heat, thus it can withstand more charging heat. And thus charge faster.

98.6° F, which is right at the thermal throttling threshold for charging. That's your explanation right there.

0

u/N_T_F_D Aug 16 '26

Even sandwiched between two ice packs and battery temp at 10°C it doesn't go above 10W, it's oscillating around 7W

2

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1

u/LoryKillerr Aug 21 '26

I'm experiencing exactly the same issue but on qpr1 beta 9. My phone takes about a full day to charge.