Fix battery voltage readouts

source/battery.cpp

@@ -20,7 +20,8 @@ void initBatteryADC() {
 float readBatteryVoltage() {
   // 8 quick reads, no delay() calls, no analogReference() change
   int32_t raw=0; for (int i=0; i<8; i++) raw += analogRead(PIN_VBAT_READ); raw /= 8;
-  return (raw / 4096.0f) * 3.0f * 2.0f;
+  // Seeed XIAO nRF52840 Sense: 1MΩ + 510kΩ voltage divider on VBAT → multiply by 1510/510
+  return (raw / 4096.0f) * 3.0f * (1510.0f / 510.0f);
 }
 
 int batteryPercent(float v) {

source/main.cpp

@@ -231,7 +231,7 @@ void setup() {
   blehid.begin();
 
   #ifdef FEATURE_BATTERY_MONITOR
-    blebas.begin(); blebas.write(100);
+    blebas.begin(); blebas.write(batteryPercent(readBatteryVoltage()));
   #endif
 
   #ifdef FEATURE_CONFIG_SERVICE

web/app.js

@@ -125,8 +125,12 @@ async function discoverServices() {
     // Telemetry notify (1 Hz) — also carries chargeStatus
     chars.telemetry.addEventListener('characteristicvaluechanged', e => parseTelemetry(e.target.value));
     await chars.telemetry.startNotifications();
-    // Initial read so values show immediately
+    // Initial read so values show immediately. Also force updateChargeUI() here
+    // because parseTelemetry() only calls it on a *change*, and currentChargeStatus
+    // starts at 0 (discharging) — so a discharging device would never trigger the
+    // update and ciStatus would stay at '--'.
     parseTelemetry(await chars.telemetry.readValue());
+    updateChargeUI();
 
     // IMU stream — subscribed on demand via play button
     chars.imuStream.addEventListener('characteristicvaluechanged', e => parseImuStream(e.target.value));