diff --git a/user/extensions.py b/user/extensions.py
index 87772cf..fb80e58 100644
--- a/user/extensions.py
+++ b/user/extensions.py
@@ -21,3 +21,6 @@ import weewx.units
 
 weewx.units.obs_group_dict['soilMoist1'] = 'group_percent'
 weewx.units.obs_group_dict['luminosity'] = 'group_illuminance'
+
+weewx.units.obs_group_dict['soilMoistBatteryVoltage1'] = 'group_volt'
+weewx.units.obs_group_dict['soilTempBatteryVoltage1'] = 'group_volt'