diff --git a/package.json b/package.json
index af69f92d..ac7a5d06 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "battery-state-card",
-  "version": "1.3.5",
+  "version": "1.3.6",
   "description": "Battery State card for Home Assistant",
   "main": "dist/battery-state-card.js",
   "repository": {
diff --git a/src/battery-vm.ts b/src/battery-vm.ts
index 21e19896..1c34ce37 100644
--- a/src/battery-vm.ts
+++ b/src/battery-vm.ts
@@ -200,9 +200,15 @@ class BatteryViewModel {
      * @param entityData Entity state data
      */
     private getLevel(entityData: HassEntity): string {
+        const UnknownLevel = "Unknown";
         let level: string;
+
         if (this.config.attribute) {
-            level = entityData.attributes[this.config.attribute]
+            level = entityData.attributes[this.config.attribute];
+            if (level == undefined) {
+                log(`Attribute "${this.config.attribute}" doesn't exist on "${this.config.entity}" entity`);
+                level = UnknownLevel;
+            }
         }
         else {
             const candidates: string[] = [
@@ -211,7 +217,7 @@ class BatteryViewModel {
                 entityData.state
             ];
 
-            level = candidates.find(n => n !== null && n !== undefined)?.toString() || "Unknown";
+            level = candidates.find(n => n !== null && n !== undefined)?.toString() || UnknownLevel;
         }
 
         // check if we should convert value eg. for binary sensors
diff --git a/src/utils.ts b/src/utils.ts
index 8629b7bc..55ab191a 100644
--- a/src/utils.ts
+++ b/src/utils.ts
@@ -1,7 +1,7 @@
 import { HomeAssistant } from "./ha-types";
 
 console.info(
-    "%c BATTERY-STATE-CARD %c 1.3.5",
+    "%c BATTERY-STATE-CARD %c 1.3.6",
     "color: white; background: forestgreen; font-weight: 700;",
     "color: forestgreen; background: white; font-weight: 700;",
 );