diff --git a/src/Controller/VehicleController.php b/src/Controller/VehicleController.php
index d09d3752..7c388062 100644
--- a/src/Controller/VehicleController.php
+++ b/src/Controller/VehicleController.php
@@ -286,6 +286,7 @@ class VehicleController extends Controller
         $batteries = $req->request->get('batteries');
         if (!empty($batteries))
         {
+            // TODO: need to move the checking for batteries to a function
             // need to check if a battery has been removed 
             if (count($current_batteries) > count($batteries))
             {
@@ -345,6 +346,61 @@ class VehicleController extends Controller
                     }
                 }
             }
+            // check if battery was deleted then another one was added
+            if (count($current_batteries) == count($batteries))
+            {
+                // find deleted battery
+                foreach ($current_batteries as $cbatt)
+                {
+                    $cbatt_id = $cbatt->getID();
+                    if (in_array($cbatt_id, $batteries))
+                    {
+                        // do nothing, move to next element
+                        continue;
+                    }
+                    else
+                    {
+                        // cbatt_id has been deleted
+                        $del_battery = $em->getRepository(Battery::class)->find($cbatt_id);
+
+                        if (!empty($del_battery))
+                        {
+                            $del_battery->removeVehicle($row);
+                        }
+                    }
+                }
+
+                // find the battery to add
+                $cbatt_ids = [];
+                foreach ($current_batteries as $cbatt)
+                {
+                    $cbatt_ids = [
+                        $cbatt->getID(),
+                    ];
+                }
+
+                foreach ($batteries as $batt)
+                {
+                    $batt_id = $batt;
+                    if (in_array($batt_id, $cbatt_ids))
+                    {
+                        // do nothing since battery already there
+                        continue;
+                    }
+                    else
+                    {
+                        // batt is the new battery
+                        $new_battery = $em->getRepository(Battery::class)->find($batt_id);
+
+                        if (!empty($new_battery))
+                        {
+                            $new_battery->addVehicle($row);
+
+                            $em->persist($new_battery);
+                        }
+                    }
+                }
+            }
         }
         else
         {