diff --git a/libnymea/interfaces/battery.json b/libnymea/interfaces/battery.json
index 43399cfe..05eeb387 100644
--- a/libnymea/interfaces/battery.json
+++ b/libnymea/interfaces/battery.json
@@ -20,13 +20,9 @@
             "optional": true
         },
         {
-            "name": "charging",
-            "type": "bool",
-            "optional": true
-        },
-        {
-            "name": "discharging",
-            "type": "bool",
+            "name": "chargingState",
+            "type": "QString",
+            "allowdValues": ["idle", "charging", "discharging"],
             "optional": true
         }
     ]
diff --git a/libnymea/interfaces/energystorage.json b/libnymea/interfaces/energystorage.json
new file mode 100644
index 00000000..866024d5
--- /dev/null
+++ b/libnymea/interfaces/energystorage.json
@@ -0,0 +1,12 @@
+{
+    "description": "Interfaces for devices that store electrical energy and can return it at a later point, such as batteries. The currentPower state follows the usual convention that positive is 'consumed' energy and negative values represent 'produced' or in this case 'returned' energy.",
+    "extends": ["battery", "smartmeter"],
+    "states": [
+        {
+            "name": "currentPower",
+            "type": "double",
+            "unit": "Watt",
+            "logged": true
+        }
+    ]
+}
diff --git a/libnymea/interfaces/interfaces.qrc b/libnymea/interfaces/interfaces.qrc
index d2996531..3d6ee2ca 100644
--- a/libnymea/interfaces/interfaces.qrc
+++ b/libnymea/interfaces/interfaces.qrc
@@ -88,5 +88,6 @@
         <file>cleaningrobot.json</file>
         <file>airquality.json</file>
         <file>indoorairquality.json</file>
+        <file>energystorage.json</file>
     </qresource>
 </RCC>