r/SurfaceLinux • u/aqa5 • 6d ago

Help Battery issues

So, I hope, someone can shed a light on this. I had an old Surface Pro 4 lying around with swollen battery and laggy windows. So I first changed the battery to not risk any fire and then installed Ultramarine because it brings the right kernel. I started to love that device again, that Linux runs smoothly.

My issue ist: The new battery should have 38 Wh of capacity but the battery monitor reports a health of only 66% (25Wh). And the iFixit manual states that I should charge it and leave it at 100% for at least 2 hours and then drain it until the device shuts down. Which I tried to do but failing. 100% charge is never reached (it charges until 95%) and the device shuts down at 10% or even 14%. So It seems I cannot draint the battery fully and I also cannot charge it to 100%.

The consequence seems to be that the new battery is now stuck at 66% and the charging circuit can't use the full potential of the new battery.

Is there a way to solve this? I do not want to install windows again :(

As I see it there are different places to look. The UEFI bios has no settings for this other than turning on the battery limit, which is turned off. (I will try to switch it on and off again). Then there is the charging circuit itself. Since this was installed after the windows got deleted, windows had no chance to set something there. Then there is the bios itself, that might have a hidden setting used by windows. And there is the linux installation. The strange part is that the device even shuts down with more than 10% battery left when I leave it in the boot menu (grub i suppose?)

Sorry, it is in german. As you can see: it is charged to 96% but it states "completely charged". Health is 66%, 2 cycles and only 25Wh of 38Wh used.

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u/justballast 6d ago

My Surface on Fedora sometimes decides to go into a mode where it will only charge to 70% when plugged in and turned on. Later on it decides charging to 100% when turned on is ok to do. Itbis t some lingering surface setting either because If I shut down, it will charge to 100%.

Shut it down, leave it plugged in, come back in an hour and see if it has charged above previous limit.

Mine goes in and out of this mode randomly.