Question Battery not being read correctly and also depleting when device is powered off ?

mrmike16 · Monday at 1:00 PM

Hi everyone,
I have been using a Microsoft Surface Pro 4 for about 2 and a half years now.
I noticed a few months ago that when it reaches around 10%, it suddenly warns me for a split second that I need to plug in my PC now and immediately shuts down - And it doesn't even give itself enough time to safely power off. It just cuts the power a split second after the shutdown screen appears.
As time went on, this happened with the percentage being higher and higher. Yesterday this happened with the battery on 50%. This seems to me a clear sign the battery is dying, but I have never seen this kind of behavior before. And I have seen my fair share of devices with low battery capacity.

Another weird behavior is when it is shut down completely. it drains the power. If I leave it off for a week, it will be completely dead. The most recent check I have done is last night, after using it plugged in for more than enough time to be fully charged (And it said it was), I turned it off and unplugged it. Today, about 15 hours later, the battery was on 92% when I turned it on. I made sure that when I turn it off, there are no fans running and the keyboard's backlight does not light up when keys are pressed. It definitely seemed to be off.

When I bought this laplet (used) to replace my fallen Surface 3 (Which still holds more of a charge than this by far), it has about 80% capacity according to Powershell, and then I did a clean installation and began using it as my main PC. This is after the previous owner left it plugged in all the time (A practice we all know is not the best for battery longevity).
Now, it's...confused, to say the least.
And no, I did not perform a clean installation since the first time. I plan on doing so when I get a new desktop.

Also, I generated this report 2 minutes ago. It was at 79%. It is now at 77%.
Sounds like a bad battery.
But maybe just calibration?

Any ideas? I definitely don't plan on replacing a Surface battery...

Surface Pro 4
Windows 10 Pro
Intel i5-6300
8GB RAM

Battery report

ME-SURFACE-P4

Microsoft Corporation Surface Pro 4

109.3748.768 05.04.2021

19041.1.amd64fre.vb_release.191206-1406

Slate

Supported

[td]COMPUTER NAME[/td] [td]SYSTEM PRODUCT NAME[/td] [td]BIOS[/td] [td]OS BUILD[/td] [td]PLATFORM ROLE[/td] [td]CONNECTED STANDBY[/td] [td]REPORT TIME[/td] [td]2025-08-18

19:53:44

[/td]

Installed batteries

Information about each currently installed battery

NAME	X910527
MANUFACTURER	SMP
SERIAL NUMBER	48865
CHEMISTRY	LION
DESIGN CAPACITY	38,152 mWh
FULL CHARGE CAPACITY	31,972 mWh
CYCLE COUNT	346

[TR]
[td][/td]
[td]BATTERY 1[/td]
[/TR]

Recent usage

Power states over the last 3 days

[TR]
[td]START TIME[/td]

[td]
STATE

[/td][td]
SOURCE

[/td][td]
CAPACITY REMAINING

[/td]

[/TR] [td]2025-08-16