diff --git a/firmware/boards/f1_dual/wideband_board_config.h b/firmware/boards/f1_dual/wideband_board_config.h
index 92593fc..5ce8f49 100644
--- a/firmware/boards/f1_dual/wideband_board_config.h
+++ b/firmware/boards/f1_dual/wideband_board_config.h
@@ -48,6 +48,13 @@
 // OpAmp with 82K + 160K
 #define AUXOUT_GAIN         ((82.0 + 160.0) / 160.0)
 
+// *******************************
+// With heater constantly on we
+// are not able to measure Vbatt
+// through Heater-
+// *******************************
+#define HEATER_MAX_DUTY		(0.85)
+
 // *******************************
 //   TunerStudio Primary Port
 // *******************************