diff --git a/libraries/AP_HAL_ChibiOS/hwdef/F35Lightning/hwdef.dat b/libraries/AP_HAL_ChibiOS/hwdef/F35Lightning/hwdef.dat
index a0e2ed1c90..9129070d33 100644
--- a/libraries/AP_HAL_ChibiOS/hwdef/F35Lightning/hwdef.dat
+++ b/libraries/AP_HAL_ChibiOS/hwdef/F35Lightning/hwdef.dat
@@ -163,6 +163,7 @@ define HAL_STORAGE_SIZE 15360
 define STORAGE_FLASH_PAGE 1
 
 # defaults for battery monitoring
+define HAL_BATT_MONITOR_DEFAULT 4
 define HAL_BATT_VOLT_PIN 11
 define HAL_BATT_CURR_PIN 12
 define HAL_BATT_VOLT_SCALE 11
diff --git a/libraries/AP_HAL_ChibiOS/hwdef/MatekF405-Wing/hwdef.dat b/libraries/AP_HAL_ChibiOS/hwdef/MatekF405-Wing/hwdef.dat
index 2ab603666f..4b3f5f1e3a 100644
--- a/libraries/AP_HAL_ChibiOS/hwdef/MatekF405-Wing/hwdef.dat
+++ b/libraries/AP_HAL_ChibiOS/hwdef/MatekF405-Wing/hwdef.dat
@@ -158,6 +158,7 @@ define HAL_BOARD_LOG_DIRECTORY "/APM/LOGS"
 define HAL_BOARD_TERRAIN_DIRECTORY "/APM/TERRAIN"
 
 # define default battery setup
+define HAL_BATT_MONITOR_DEFAULT 4
 define HAL_BATT_VOLT_PIN 10
 define HAL_BATT_CURR_PIN 11
 define HAL_BATT_VOLT_SCALE 11