diff --git a/lib/hal/HalGPIO.cpp b/lib/hal/HalGPIO.cpp
index 1c0e7171c4..4a2c8e01e9 100644
--- a/lib/hal/HalGPIO.cpp
+++ b/lib/hal/HalGPIO.cpp
@@ -9,13 +9,6 @@
 HalGPIO gpio;
 
 namespace {
-constexpr uint8_t I2C_ADDR_BQ27220 = 0x55;
-constexpr uint8_t I2C_ADDR_DS3231 = 0x68;
-constexpr uint8_t I2C_ADDR_QMI8658 = 0x6B;
-constexpr uint8_t I2C_ADDR_QMI8658_ALT = 0x6A;
-constexpr uint8_t QMI8658_WHO_AM_I_REG = 0x00;
-constexpr uint8_t QMI8658_WHO_AM_I_VALUE = 0x05;
-
 constexpr char HW_NAMESPACE[] = "cphw";
 constexpr char NVS_KEY_DEV_OVERRIDE[] = "dev_ovr";  // 0=auto, 1=x4, 2=x3
 constexpr char NVS_KEY_DEV_CACHED[] = "dev_det";    // 0=unknown, 1=x4, 2=x3
@@ -65,7 +58,7 @@ bool readI2CReg16LE(uint8_t addr, uint8_t reg, uint16_t* outValue) {
 
 bool readBQ27220CurrentMA(int16_t* outCurrent) {
   uint16_t raw = 0;
-  if (!readI2CReg16LE(I2C_ADDR_BQ27220, 0x0C, &raw)) {
+  if (!readI2CReg16LE(I2C_ADDR_BQ27220, BQ27220_CUR_REG, &raw)) {
     return false;
   }
   *outCurrent = static_cast<int16_t>(raw);
@@ -75,13 +68,13 @@ bool readBQ27220CurrentMA(int16_t* outCurrent) {
 bool probeBQ27220Signature() {
   uint16_t soc = 0;
   uint16_t voltageMv = 0;
-  if (!readI2CReg16LE(I2C_ADDR_BQ27220, 0x2C, &soc)) {
+  if (!readI2CReg16LE(I2C_ADDR_BQ27220, BQ27220_SOC_REG, &soc)) {
     return false;
   }
   if (soc > 100) {
     return false;
   }
-  if (!readI2CReg16LE(I2C_ADDR_BQ27220, 0x08, &voltageMv)) {
+  if (!readI2CReg16LE(I2C_ADDR_BQ27220, BQ27220_VOLT_REG, &voltageMv)) {
     return false;
   }
   return voltageMv >= 2500 && voltageMv <= 5000;
@@ -89,11 +82,13 @@ bool probeBQ27220Signature() {
 
 bool probeDS3231Signature() {
   uint8_t sec = 0;
-  if (!readI2CReg8(I2C_ADDR_DS3231, 0x00, &sec)) {
+  if (!readI2CReg8(I2C_ADDR_DS3231, DS3231_SEC_REG, &sec)) {
     return false;
   }
-  const uint8_t secBcd = sec & 0x7F;
-  return secBcd <= 0x59;
+  const uint8_t tensDigit = (sec >> 4) & 0x07;
+  const uint8_t onesDigit = sec & 0x0F;
+
+  return tensDigit <= 5 && onesDigit <= 9;
 }
 
 bool probeQMI8658Signature() {
@@ -109,7 +104,7 @@ bool probeQMI8658Signature() {
 
 X3ProbeResult runX3ProbePass() {
   X3ProbeResult result;
-  Wire.begin(20, 0, 400000);
+  Wire.begin(X3_I2C_SDA, X3_I2C_SCL, X3_I2C_FREQ);
   Wire.setTimeOut(6);
 
   result.bq27220 = probeBQ27220Signature();
diff --git a/lib/hal/HalGPIO.h b/lib/hal/HalGPIO.h
index ff6ed74fb7..f9ecb0dfb3 100644
--- a/lib/hal/HalGPIO.h
+++ b/lib/hal/HalGPIO.h
@@ -17,6 +17,27 @@
 
 #define UART0_RXD 20  // Used for USB connection detection
 
+// Xteink X3 Hardware
+#define X3_I2C_SDA 20
+#define X3_I2C_SCL 0
+#define X3_I2C_FREQ 400000
+
+// TI BQ27220 Fuel gauge I2C
+#define I2C_ADDR_BQ27220 0x55  // Fuel gauge I2C address
+#define BQ27220_SOC_REG 0x2C   // StateOfCharge() command code (%)
+#define BQ27220_CUR_REG 0x0C   // Current() command code (signed mA)
+#define BQ27220_VOLT_REG 0x08  // Voltage() command code (mV)
+
+// Analog DS3231 RTC I2C
+#define I2C_ADDR_DS3231 0x68  // RTC I2C address
+#define DS3231_SEC_REG 0x00   // Seconds command code (BCD)
+
+// QST QMI8658 IMU I2C
+#define I2C_ADDR_QMI8658 0x6B        // IMU I2C address
+#define I2C_ADDR_QMI8658_ALT 0x6A    // IMU I2C fallback address
+#define QMI8658_WHO_AM_I_REG 0x00    // WHO_AM_I command code
+#define QMI8658_WHO_AM_I_VALUE 0x05  // WHO_AM_I expected value
+
 class HalGPIO {
 #if CROSSPOINT_EMULATED == 0
   InputManager inputMgr;
diff --git a/lib/hal/HalPowerManager.cpp b/lib/hal/HalPowerManager.cpp
index 95f24d7713..584ee06d9c 100644
--- a/lib/hal/HalPowerManager.cpp
+++ b/lib/hal/HalPowerManager.cpp
@@ -14,12 +14,9 @@ void HalPowerManager::begin() {
   if (gpio.deviceIsX3()) {
     // X3 uses an I2C fuel gauge for battery monitoring.
     // I2C init must come AFTER gpio.begin() so early hardware detection/probes are finished.
-    Wire.begin(20, 0, 400000);
+    Wire.begin(X3_I2C_SDA, X3_I2C_SCL, X3_I2C_FREQ);
     Wire.setTimeOut(4);
     _batteryUseI2C = true;
-    _batteryI2cAddr = 0x55;
-    // TI BQ27220: StateOfCharge() command code
-    _batterySocRegister = 0x2C;
   } else {
     pinMode(BAT_GPIO0, INPUT);
   }
@@ -84,16 +81,14 @@ uint16_t HalPowerManager::getBatteryPercentage() const {
 
     // Read SOC directly from I2C fuel gauge (16-bit LE register).
     // On I2C error, keep last known value to avoid UI jitter/slowdowns.
-    Wire.beginTransmission(_batteryI2cAddr);
-    Wire.write(_batterySocRegister);
+    Wire.beginTransmission(I2C_ADDR_BQ27220);
+    Wire.write(BQ27220_SOC_REG);
     if (Wire.endTransmission(false) != 0) {
-      _batteryI2cFailCount++;
       _batteryLastPollMs = now;
       return _batteryCachedPercent;
     }
-    Wire.requestFrom(_batteryI2cAddr, (uint8_t)2);
+    Wire.requestFrom(I2C_ADDR_BQ27220, (uint8_t)2);
     if (Wire.available() < 2) {
-      _batteryI2cFailCount++;
       _batteryLastPollMs = now;
       return _batteryCachedPercent;
     }
@@ -102,7 +97,6 @@ uint16_t HalPowerManager::getBatteryPercentage() const {
     const uint16_t soc = (hi << 8) | lo;
     _batteryCachedPercent = soc > 100 ? 100 : soc;
     _batteryLastPollMs = now;
-    _batteryI2cFailCount = 0;
     return _batteryCachedPercent;
   }
   static const BatteryMonitor battery = BatteryMonitor(BAT_GPIO0);
diff --git a/lib/hal/HalPowerManager.h b/lib/hal/HalPowerManager.h
index 5bebd6c31d..bf78623ca3 100644
--- a/lib/hal/HalPowerManager.h
+++ b/lib/hal/HalPowerManager.h
@@ -19,12 +19,9 @@ class HalPowerManager {
   bool isLowPower = false;
 
   // I2C fuel gauge configuration for X3 battery monitoring
-  bool _batteryUseI2C = false;
-  uint8_t _batteryI2cAddr = 0;
-  uint8_t _batterySocRegister = 0;
-  mutable int _batteryCachedPercent = 0;
-  mutable unsigned long _batteryLastPollMs = 0;
-  mutable uint8_t _batteryI2cFailCount = 0;
+  bool _batteryUseI2C = false;                   // True if using I2C fuel gauge (X3), false for ADC (X4)
+  mutable int _batteryCachedPercent = 0;         // Last read battery percentage (0-100)
+  mutable unsigned long _batteryLastPollMs = 0;  // Timestamp of last battery read in milliseconds
 
   enum LockMode { None, NormalSpeed };
   LockMode currentLockMode = None;