diff --git a/libraries/AP_HAL_ChibiOS/hwdef/FSOPowerStack/defaults.parm b/libraries/AP_HAL_ChibiOS/hwdef/FSOPowerStack/defaults.parm
index 647b9e37aa275..4bc4e604b55ca 100644
--- a/libraries/AP_HAL_ChibiOS/hwdef/FSOPowerStack/defaults.parm
+++ b/libraries/AP_HAL_ChibiOS/hwdef/FSOPowerStack/defaults.parm
@@ -52,6 +52,11 @@ BATT8_I2C_ADDR 69
 BATT8_SHUNT 0.001
 BATT8_MAX_AMPS 5
 
+# Main Out
+BATT9_MONITOR 3
+BATT9_VOLT_PIN 90
+BATT9_VOLT_MULT 19
+
 # LED setup
 OUT1_FUNCTION 120
 
diff --git a/libraries/AP_HAL_ChibiOS/hwdef/FSOPowerStack/hwdef.dat b/libraries/AP_HAL_ChibiOS/hwdef/FSOPowerStack/hwdef.dat
index 01a0fdd8e169b..15d6643d6acce 100644
--- a/libraries/AP_HAL_ChibiOS/hwdef/FSOPowerStack/hwdef.dat
+++ b/libraries/AP_HAL_ChibiOS/hwdef/FSOPowerStack/hwdef.dat
@@ -31,7 +31,7 @@ define HAL_PERIPH_ENABLE_RC_OUT
 define HAL_PERIPH_ENABLE_NOTIFY
 define HAL_PERIPH_ENABLE_FSO_POWER_STACK
 
-define AP_BATT_MONITOR_MAX_INSTANCES 8
+define AP_BATT_MONITOR_MAX_INSTANCES 9
 define AP_BATTERY_BACKEND_DEFAULT_ENABLED 0
 define AP_BATTERY_INA2XX_ENABLED 1
 define AP_BATTERY_ANALOG_ENABLED 1
@@ -133,8 +133,13 @@ PC13    MAIN_PC         OUTPUT  PULLDOWN    GPIO(74)    LOW
 PC14    BAT_1_EN        OUTPUT  PULLDOWN    GPIO(75)    LOW
 PC15    BAT_2_EN        OUTPUT  PULLDOWN    GPIO(76)    LOW
 
-define FSO_PAYLOAD_PC_PIN 70
-define FSO_PAYLOAD_EN_PIN 71
+define FSO_PAYLOAD_HV_PC_PIN 70
+define FSO_PAYLOAD_HV_EN_PIN 71
+define FSO_PAYLOAD_1_EN_PIN 72
+define FSO_PAYLOAD_2_EN_PIN 73
+define FSO_MAIN_PC_PIN 74
+define FSO_BAT_1_EN_PIN 75
+define FSO_BAT_2_EN_PIN 76
 
 # LEDs
 PA1     LED_RED     OUTPUT  PULLDOWN    GPIO(80)    LOW
@@ -145,6 +150,7 @@ PB2     LED_BOOT    OUTPUT  PULLDOWN    GPIO(84)    LOW
 PB13    LED_MAIN    OUTPUT  PULLDOWN    GPIO(85)    LOW
 PB15    LED_PAYLOAD OUTPUT  PULLDOWN    GPIO(86)    LOW
 
+define FSO_LED_DEBUG_PIN 84
 define FSO_LED_MAIN_PIN 85
 define FSO_LED_PAYLOAD_PIN 86