From b8fd9cd0dc73f28c3b4f7e0faf6c5568550e404d Mon Sep 17 00:00:00 2001
From: kj_sh604
Date: Thu, 19 Feb 2026 22:35:53 -0500
Subject: feat: new thinkpad battery script

---
 .local/bin/bat-thresh-toggle | 103 +++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 103 insertions(+)
 create mode 100755 .local/bin/bat-thresh-toggle

diff --git a/.local/bin/bat-thresh-toggle b/.local/bin/bat-thresh-toggle
new file mode 100755
index 0000000..2819132
--- /dev/null
+++ b/.local/bin/bat-thresh-toggle
@@ -0,0 +1,103 @@
+#!/bin/sh
+
+THRESH_START_PATH="/sys/class/power_supply/BAT0/charge_control_start_threshold"
+THRESH_STOP_PATH="/sys/class/power_supply/BAT0/charge_control_end_threshold"
+TLP_DROP_IN="/etc/tlp.d/05-bat-thresh.conf"
+
+TRAVEL_START=85
+TRAVEL_STOP=99
+DOCKED_START=75
+DOCKED_STOP=89
+DEFAULT_START=96
+DEFAULT_STOP=100
+
+usage() {
+    cat <<EOF
+usage: $(basename "$0") [OPTION]
+
+toggles BAT0 charge thresholds between travel and docked modes,
+writing a persistent TLP drop-in to ${TLP_DROP_IN}.
+
+options:
+  (none)             toggle between travel (${TRAVEL_START}/${TRAVEL_STOP}%) and docked (${DOCKED_START}/${DOCKED_STOP}%)
+  --system-default   restore TLP built-in defaults (${DEFAULT_START}/${DEFAULT_STOP}%) and remove drop-in
+  -h, --help         show this help message and exit
+
+modes:
+  travel           START_CHARGE_THRESH_BAT0=${TRAVEL_START}   STOP_CHARGE_THRESH_BAT0=${TRAVEL_STOP}
+  docked           START_CHARGE_THRESH_BAT0=${DOCKED_START}   STOP_CHARGE_THRESH_BAT0=${DOCKED_STOP}
+  system-default   START_CHARGE_THRESH_BAT0=${DEFAULT_START}   STOP_CHARGE_THRESH_BAT0=${DEFAULT_STOP}
+
+EOF
+}
+
+case "${1}" in
+    -h|--help) usage; exit 0 ;;
+esac
+
+# gotta be root to write to sysfs
+if [ "$(id -u)" -ne 0 ]; then
+    usage
+    sleep 1
+    echo "error: script must be run as root."; echo ""
+    exit 1
+fi
+
+# make sure the sysfs nodes are actually there
+[ -f "$THRESH_START_PATH" ] || { echo "error: $THRESH_START_PATH not found — is thinkpad_acpi loaded?"; exit 1; }
+[ -f "$THRESH_STOP_PATH" ]  || { echo "error: $THRESH_STOP_PATH not found — is thinkpad_acpi loaded?"; exit 1; }
+
+# --system-default: remove drop-in and restore TLP built-in defaults (96/100)
+if [ "${1}" = "--system-default" ]; then
+    printf "%s" "$DEFAULT_STOP"  > "$THRESH_STOP_PATH"  || { echo "error: failed to write stop threshold.";  exit 1; }
+    printf "%s" "$DEFAULT_START" > "$THRESH_START_PATH" || { echo "error: failed to write start threshold."; exit 1; }
+    echo "restored system defaults — start: ${DEFAULT_START}%  stop: ${DEFAULT_STOP}%"
+    if [ -f "$TLP_DROP_IN" ]; then
+        rm "$TLP_DROP_IN" \
+            && echo "${TLP_DROP_IN} removed — TLP will use its built-in defaults after reboot." \
+            || echo "error: failed to remove ${TLP_DROP_IN}."
+    else
+        echo "note: ${TLP_DROP_IN} was not present — nothing to remove."
+    fi
+    exit 0
+fi
+
+current_stop=$(cat "$THRESH_STOP_PATH")
+
+# determine which mode to switch INTO based on the current stop threshold
+case "$current_stop" in
+    "$TRAVEL_STOP")
+        target_mode="docked"
+        new_start="$DOCKED_START"
+        new_stop="$DOCKED_STOP"
+        ;;
+    *)
+        target_mode="travel"
+        new_start="$TRAVEL_START"
+        new_stop="$TRAVEL_STOP"
+        ;;
+esac
+
+# the kernel enforces start < stop at all times, so write order matters
+case "$target_mode" in
+    travel)
+        printf "%s" "$new_stop"  > "$THRESH_STOP_PATH"  || { echo "error: failed to write stop threshold.";  exit 1; }
+        printf "%s" "$new_start" > "$THRESH_START_PATH" || { echo "error: failed to write start threshold."; exit 1; }
+        ;;
+    docked)
+        printf "%s" "$new_start" > "$THRESH_START_PATH" || { echo "error: failed to write start threshold."; exit 1; }
+        printf "%s" "$new_stop"  > "$THRESH_STOP_PATH"  || { echo "error: failed to write stop threshold.";  exit 1; }
+        ;;
+esac
+
+echo "switched to $target_mode mode — start: ${new_start}%  stop: ${new_stop}%"
+
+# write a dedicated drop-in so thresholds survive a reboot; no sed fragility
+if [ -d "/etc/tlp.d" ]; then
+    printf '# managed by bat-thresh-toggle — do not edit by hand\nSTART_CHARGE_THRESH_BAT0=%s\nSTOP_CHARGE_THRESH_BAT0=%s\n' \
+        "$new_start" "$new_stop" > "$TLP_DROP_IN" \
+        && echo "${TLP_DROP_IN} written" \
+        || echo "error: failed to write ${TLP_DROP_IN}."
+else
+    echo "note: /etc/tlp.d not found - sysfs write is not persistent across reboots."
+fi
\ No newline at end of file
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