Charging the battery to 80% does not work

iii

When the phone is turned on and plugged in, I have noticed that even when bypass charging is active on my Pixel 6a, the battery status alternates between "CHARGING" and "NOT_CHARGING", even when using the OEM charger and OEM USB C cable.

termux-battery-status (link) can be used to query for battery status, and the shield icon in the status bar should indicate that battery charging is on:

it has bypass charging to use power directly from the charger without going through the battery. It shows the shield icon while doing this.

From https://discuss.grapheneos.org/d/18611-grapheneos-version-2024123000-released/63

doublefree

iii When the phone is turned on and plugged in, I have noticed that even when bypass charging is active on my Pixel 6a, the battery status alternates between "CHARGING" and "NOT_CHARGING"

Confirmed with "CPU Info" app in Pixel 6. Every few minutes it changes to charging for a few seconds.

dendereTI9070

collector Yes, I meant I completely turned off the phone. But well, it seems like it's not the fault of the GrapheneOS-Team, judging by the article linked by the user @DeletedUser217 : https://9to5google.com/2025/01/02/psa-pixel-80-charge-limit-doesnt-work-while-your-device-is-powered-off/ .
Although would have been nice if the GrapheneOS-team mentioned it somewhere...or maybe an official reply here from the GrapheneOS-team? I mean just so we have an official confirmation.

GrapheneOS

This only applies while the OS is booted into the regular boot mode. The OS configures charging to work this way. There's nothing which can be set to make it happen without the OS booted. When the device is off, it normally boots into the OS charging mode when plugged in unless it's at an extremely low battery level near 0%. In theory, the OS could implement this charge limit there. It's not currently something implemented by the stock OS or at a low-level by the Android Open Source Project. It's not something we currently plan to add unless the stock OS adds it.

de0u

doublefree Every few minutes it changes to charging for a few seconds.

Is this behavior observed also on Google's stock OS?

DeletedUser64

doublefree

"Whenever lithium-ion batteries has to be kept in the charger for functional ability, some chargers implement a short filling charge to pay for the little self-discharge the battery and its shielding circuit take in."

not my words but a direct quote from...
https://makingcircuits.com/blog/how-to-charge-a-li-ion-battery-correctly-and-safely/

doublefree

de0u I don't have a phone to test.

trilogy6202

doublefree This is pure speculation but my guess is that this is intended behavior in order to ensure that the battery stays at 80% over time as the battery would otherwise slowly discharge over time when bypassed.

The_Defector

The "Charging Optomization" also states that it will "occasionally charge to 100% to recalibrate estimated capacity". Curious what "occasionally" actually means.

andrej567

it happened to me today and yesterday, charging went up to 100%
i used the same charger as always.. i will check what happens next time.
pixel 7a, latest os.

Lilac6044

andrej567 Occasionally your phone will charge to 100% anyway to recalibrate, so it is likely intended behaviour in your case.

andrej567

Lilac6044 I know, occasionally. I happened now the 3rd charging in a row

f13a-6c3a

Read the last few posts on this thread: https://discuss.grapheneos.org/d/20620-charging-optimization-80-charge-limit-recalibration-with-android-15-qpr2