diff --git a/libnymea/interfaces/energystorage.json b/libnymea/interfaces/energystorage.json
index 866024d5..0bb56c01 100644
--- a/libnymea/interfaces/energystorage.json
+++ b/libnymea/interfaces/energystorage.json
@@ -7,6 +7,11 @@
             "type": "double",
             "unit": "Watt",
             "logged": true
+        },
+        {
+            "name": "capacity",
+            "type": "double",
+            "unit": "WattHour"
         }
     ]
 }