Microsoft Surface Pro - Not detecting the Battery

[Peritia-System]

Hi there,

I can’t get the battery to show up on my Surface devices.
From my perspective the config should work, but it only detects the AC adapter.
I also tested on two different Surfaces, so it doesn’t seem to be hardware related.
I couldn't find an Issue related to this problem nor that it is known not to work.

Here the Code Snippets:

# hardware-configuration.nix
  boot.initrd.availableKernelModules = ["xhci_pci" "nvme"];
  boot.initrd.kernelModules = [];
  boot.kernelModules = ["kvm-intel"];
  boot.extraModulePackages = [];
 # rest of the Hardware configuration ....

I am using the kernelVersion = "stable";

# Additional-Hardware-config.nix
    hardware.microsoft-surface.kernelVersion = "stable";
    # boot.kernelPackages = pkgs.linuxPackages_6_6; # normally set by nixos-hardware

    # Extra kernel modules
    boot.kernelModules = [ "hid-microsoft" "battery" "ac" ];

    hardware.enableAllFirmware = true;
    # Initrd modules — required for Surface hardware to function
    boot.initrd.kernelModules = [
      # Surface Aggregator Module (SAM): buttons, sensors, keyboard
      "surface_aggregator"
      "surface_aggregator_registry"
      "surface_aggregator_hub"
      "surface_hid_core"
      "surface_hid"

      # Intel Low Power Subsystem (keyboard, I2C, etc.)
      "intel_lpss"
      "intel_lpss_pci"
      "8250_dw"
    ];

    environment.systemPackages = with pkgs; [
      #for camera
      libcamera

      # for Battery 
      tlp
      upower
      acpi
    ];

    # IPTSd not required — touchscreen and pen work via HID
    services.iptsd.enable = lib.mkForce false;

    services.thermald = {
      enable = true;
      configFile = ./thermal-conf.xml;
      # Example: extra options if needed
      # extraOptions = [
      #   "--adaptive"
      #   "--max-temperature=65"
      # ];
    };

here maybe some additional information:

dmesg | grep -i battery

… surface_acpi_notify … battery … surface_hid …

cat /sys/class/power_supply/*/uevent

DEVTYPE=power_supply
POWER_SUPPLY_NAME=ADP1
POWER_SUPPLY_TYPE=Mains
POWER_SUPPLY_ONLINE=0
POWER_SUPPLY_TYPE=Mains

upower -e

/org/freedesktop/UPower/devices/line_power_ADP1
/org/freedesktop/UPower/devices/DisplayDevice

acpi -V

Adapter 0: off-line
Cooling 0: Processor 0 of 10
…

upower -i /org/freedesktop/UPower/devices/battery_BAT0

native-path:          (null)
power supply:         no
updated:              Do 01 Jan 1970 01:00:00 CET
has history:          no
has statistics:       no
unknown
  warning-level:       unknown
  battery-level:       unknown
  percentage:          0% (should be ignored)
  icon-name:          '(null)'

[Peritia-System]

I forgot to mention since it might be helpful:

• nixos-hardware commit hash: 321cb2173bc3a6a2ccb1d50dea2373950720efad
• Kernel: 6.15.9
• Host: Microsoft Corporation Surface Pro
• OS: NixOS 25.11
• CPU: Intel i5-7300U (4) @ 3.5GHz
• Import: nixos-hardware.nixosModules.microsoft-surface-pro-intel from
  github:NixOS/nixos-hardware?rev=321cb2173bc3a6a2ccb1d50dea2373950720efad

[Peritia-System]

I tested more and i cannot solve it
Is this an known issue or does it work for anyone?