diff --git a/src/board/system76/lemp12/board.mk b/src/board/system76/lemp12/board.mk
index b7ecdf1..f716504 100644
--- a/src/board/system76/lemp12/board.mk
+++ b/src/board/system76/lemp12/board.mk
@@ -26,13 +26,15 @@ CFLAGS+=-DI2C_SMBUS=I2C_4
 CFLAGS+=-DPS2_TOUCHPAD=PS2_3
 
 # Set smart charger parameters
+#TODO: why is psys gain 0.5uA/W
 CHARGER=oz26786
 CFLAGS+=\
 	-DCHARGER_ADAPTER_RSENSE=5 \
 	-DCHARGER_BATTERY_RSENSE=5 \
 	-DCHARGER_CHARGE_CURRENT=3072 \
 	-DCHARGER_CHARGE_VOLTAGE=8800 \
-	-DCHARGER_INPUT_CURRENT=3420
+	-DCHARGER_INPUT_CURRENT=3420 \
+	-DCHARGER_PSYS_GAIN=500
 
 # Add system76 common code
 include src/board/system76/common/common.mk