diff --git a/src/Controller/RAPIController.php b/src/Controller/RAPIController.php
index cad01b82..7b66312d 100644
--- a/src/Controller/RAPIController.php
+++ b/src/Controller/RAPIController.php
@@ -771,7 +771,7 @@ class RAPIController extends Controller
             $jo->setORNum($or_num);
 
         // check battery id
-        $batt_id = $req->request->get('batt_id');
+        $batt_id = $req->request->get('batt_id', null);
         // no battery
         if ($batt_id == 0 || $batt_id == null)
             $battery = null;