diff --git a/src/open9x.cpp b/src/open9x.cpp
index 518f2b358..6fe109a16 100644
--- a/src/open9x.cpp
+++ b/src/open9x.cpp
@@ -3441,12 +3441,12 @@ void perMain()
     counter = 10;
 #if defined(PCBX9D)
     int32_t instant_vbat = anaIn(TX_VOLTAGE);
-    instant_vbat = ( instant_vbat + instant_vbat*(g_eeGeneral.vBatCalib)/128 ) * 150 ;
+    instant_vbat = ( instant_vbat + instant_vbat*(g_eeGeneral.vBatCalib)/128 ) * BATT_SCALE;
     instant_vbat >>= 11;
 #elif defined(PCBSKY9X)
     int32_t instant_vbat = anaIn(TX_VOLTAGE);
-    instant_vbat = ( instant_vbat + instant_vbat*(g_eeGeneral.vBatCalib)/128 ) * 4191 ;
-    instant_vbat /= 55296  ;
+    instant_vbat = ( instant_vbat + instant_vbat*(g_eeGeneral.vBatCalib)/128 ) * 4191;
+    instant_vbat /= 55296;
 #elif defined(PCBGRUVIN9X)
     uint16_t instant_vbat = anaIn(TX_VOLTAGE);
     instant_vbat = ((uint32_t)instant_vbat*1112 + (int32_t)instant_vbat*g_eeGeneral.vBatCalib + (BandGap<<2)) / (BandGap<<3);
diff --git a/src/x9d/board_x9d.h b/src/x9d/board_x9d.h
index 9f601eeeb..a6fbec137 100644
--- a/src/x9d/board_x9d.h
+++ b/src/x9d/board_x9d.h
@@ -134,6 +134,11 @@ void watchdogInit();
 void adcInit();
 void adcRead();
 extern volatile uint16_t Analog_values[];
+#if defined(REV3)
+  #define BATT_SCALE    120
+#else
+  #define BATT_SCALE    150
+#endif
 
 // Power driver
 void pwrInit();