diff --git a/apps/counter/api/serializers.py b/apps/counter/api/serializers.py
index 7ef106c..ba5aae7 100644
--- a/apps/counter/api/serializers.py
+++ b/apps/counter/api/serializers.py
@@ -56,6 +56,8 @@ class DeviceCountSerializer(serializers.ModelSerializer):
         return obj.csq
 
     def get_energy(self, obj):
+        if float(obj.vol) <= 100:
+            return '{}{}'.format(round(float(obj.vol), 1), '%')
         return get_vol(obj.device_id, obj.vol)
 
     def get_calc_time(self, obj):
@@ -144,6 +146,8 @@ class DeviceInfoSerializer(serializers.ModelSerializer):
 
     def get_energy(self, obj):
         if self.latest:
+            if float(self.latest.vol) <= 100:
+                return '{}{}'.format(round(float(self.latest.vol), 1), '%')
             return get_vol(obj.device_id, self.latest.vol)
         return 0