diff --git a/src/batterymonitor.cpp b/src/batterymonitor.cpp
index eb11771..a26b923 100644
--- a/src/batterymonitor.cpp
+++ b/src/batterymonitor.cpp
@@ -42,7 +42,7 @@ void BatteryMonitor::Loop()
             level = voltage_3_3 - level;
             if (level < 50)
             {
-                voltage = 4.0F;
+                voltage = 5.0F;
             }
             else
             {
@@ -52,7 +52,8 @@ void BatteryMonitor::Loop()
 #endif
 #if BATTERY_MONITOR_EXTERNAL
         last_battery_sample = now_ms;
-        voltage = ((float)analogRead(PIN_BATTERY_LEVEL)) * batteryADCMultiplier;
+        float e = ((float)analogRead(PIN_BATTERY_LEVEL)) * batteryADCMultiplier;
+        voltage = (voltage > 0) ? min(voltage, e) : e;
 #endif
 #if BATTERY_MONITOR_MCP3021
         if (address > 0)
@@ -65,6 +66,7 @@ void BatteryMonitor::Loop()
             if (status == 0)
             {
                 float v = (((uint16_t)(MSB & 0x0F) << 6) | (uint16_t)(LSB >> 2));
+                v *= batteryADCMultiplier;
                 voltage = (voltage > 0) ? min(voltage, v) : v;
             }
         }
diff --git a/src/defines.h b/src/defines.h
index fcc3fd9..ff2a992 100644
--- a/src/defines.h
+++ b/src/defines.h
@@ -129,5 +129,9 @@
   // SlimeVR Board can handle max 5V > so analogRead of 5.0V input will result in 1023.0
   #define batteryADCMultiplier 1.0 / 1023.0 * (320 + BATTERY_MONITOR_EXTERNAL) / 100
 #endif
+#if BATTERY_MONITOR_MCP3021
+  // Default recommended resistors are 9.1k and 5.1k
+  #define batteryADCMultiplier 3.3 / 1023.0 * 14.2 / 9.1
+#endif
 
 #endif // SLIMEVR_DEFINES_H_