diff --git a/options/custom/services/power-profiles-daemon.nix b/options/custom/services/power-profiles-daemon.nix
index 1d6a870..785552b 100644
--- a/options/custom/services/power-profiles-daemon.nix
+++ b/options/custom/services/power-profiles-daemon.nix
@@ -1,12 +1,18 @@
 {
   config,
   lib,
+  pkgs,
   ...
 }:
 with lib; let
+  powerprofilesctl = "${pkgs.power-profiles-daemon}/bin/powerprofilesctl";
+
   cfg = config.custom.services.power-profiles-daemon;
 in {
-  options.custom.services.power-profiles-daemon.enable = mkOption {default = false;};
+  options.custom.services.power-profiles-daemon = {
+    enable = mkOption {default = false;};
+    auto = mkOption {default = true;};
+  };
 
   config = mkIf cfg.enable {
     # https://gitlab.freedesktop.org/upower/power-profiles-daemon
@@ -14,7 +20,20 @@ in {
     #?? powerprofilesctl set <performance|balanced|power-saver>
     services = {
       power-profiles-daemon.enable = true;
-      tlp.enable = false; # Conflicts with PPD
+
+      #!! Conflicts with power-profiles-daemon
+      auto-cpufreq.enable = false;
+      tlp.enable = false;
+
+      # Switch to power-saver mode when on battery
+      # https://wiki.archlinux.org/title/Power_management#Using_a_script_and_an_udev_rule
+      udev.extraRules = mkIf cfg.auto ''
+        # Battery
+        SUBSYSTEM=="power_supply", ATTR{online}=="0", RUN+="${powerprofilesctl} set power-saver"
+
+        # AC
+        SUBSYSTEM=="power_supply", ATTR{online}=="1", RUN+="${powerprofilesctl} set balanced"
+      '';
     };
   };
 }