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  • Charging optimization (80% charge limit) recalibration with Android 15 QPR2

As explained in the Settings > Battery > Charging optimization description below the toggle, the device will occasionally need to charge to 100% in order to recalibrate estimated battery capacity. The recalibration seemingly didn't work before Android 15 QPR2 but has been fixed. For most users with this feature enabled, you're due for a recalibration which will happen after updating to the latest GrapheneOS releases based on QPR2. 2025030700 will be reaching the Stable channel soon. Once it reaches 100%, it needs to be allowed to stay there for a bit to truly reach full battery charge. The shield icon showing charging bypass is active will appear. After the shield appears, it will go back to not charging the battery above 80% again. Since it has charging bypass, it won't start dropping from 100% much until you unplug it since it's directly powered from the charging cable as usual.

Many people were confused by this with the stock Pixel OS after updating to Android 15 QPR2 and believed the feature wasn't working anymore. We decided to get ahead of the confusion and make a post explaining it before it reaches Stable today.

    Very well, thank you. I was about to report it not working :)

    The UI in Settings > Battery is very confusing here. It states "Done charging" just like usually when charging bypass is turned on. I find it odd that upstream didn't add "recalibration" or similar status to be used for this process.

      Wow didn't even know direct charging was a thing. Two One unrelated question:

      • Shouldn't there be an option to disable fast charging in the battery menu? I guess it must not be in AOSP to begin with.
      • The OS only displays how many cycles were made on the battery, is there a way to check the % health of the battery?

      The best thing for battery health will be using the battery optimization feature and leaving the device plugged in as much as possible to take advantage of bypass charging instead of repeatedly draining and charging the battery. It needs to have proper USB-PD for that to work well, so disabling fast charging would be at odds with the bypass charging feature.

      The OS only displays how many cycles were made on the battery, is there a way to check the % health of the battery?

      It estimates the capacity but it's not shown in the regular user interface as far as we know. You can check it via ADB shell via /sys/class/power_supply/battery/charge_full but we don't recommend using ADB on a production device. We could potentially add the info to the Settings app.

        Question - is the bypass charging feature in effect when the 80% is turned on? Meaning, when charging to 80% and leave the charging cable plugged in, would it trigger the bypass charging feature and not charging the battery over 80%?

          The 80% feature seems to be bugged now on the Pixel Tablet. It will keep charging to 90%. My guess is that it's trying to reach 100% for the calibration, but it can't reach it because it's limited to 90% elsewhere.

          GrapheneOS Since you mention best practices, particularly regarding bypass charging with USB-PD, I would like your thoughts on low charging for comparison. Does charging the phone battery with an underpowered charger( 5V 550mA, 2.75W for instance) and keep the battery between 20% and 80% a good practice for battery life ? How do you think this compares to using USB-PD in the long run? Is there a risk of damaging the battery with an underpowered charger?

          • xxx replied to this.

              My tablet loads to 94% and says it is fully loaded. Is it supposed to be like that? Is the real capacity 94% and it will load to 80% of that after calibration?

              Does bypass charging work on Pixel 7?

              On stock Android bypass charging is only available for Pixel 8 and newer, but my Pixel 7 Pro does have the 80% charge limit, does it mean I also have bypass charging and can leave the phone plugged in?

                When it reached 100% I had to leave my phone plugged in for nearly half an hour before the shield icon appeared. Just an FYI for other impatient souls out there. 😊

                  I have a question: Does the bypass charging also works with wireless charging (Qi)?

                    I only got to 98% before the shield appeared. I left the phone charging overnight, around 7 hours in total. It's my first charge after installing 2026030800. Is this working correctly? It used to hit 100% before charging optimisation was switched on.

                    • de0u replied to this.

                      Popped on to see what the fuss was about (mine went above 80% too). Thanks for the info @GrapheneOS about how this (+recalibration) actually works 😁👍

                      wagg3r I would suggest waiting a week to see what happens.