diff --git a/src/Command/MergeDuplicateVehiclesCommand.php b/src/Command/MergeDuplicateVehiclesCommand.php
new file mode 100644
index 00000000..a0b729cd
--- /dev/null
+++ b/src/Command/MergeDuplicateVehiclesCommand.php
@@ -0,0 +1,168 @@
+<?php
+
+namespace App\Command;
+
+use Symfony\Component\Console\Command\Command;
+use Symfony\Component\Console\Input\InputArgument;
+use Symfony\Component\Console\Input\InputInterface;
+use Symfony\Component\Console\Output\OutputInterface;
+
+use Doctrine\Common\Persistence\ObjectManager;
+
+use App\Entity\Vehicle;
+
+class MergeDuplicateVehiclesCommand  extends Command
+{
+    protected $em;
+
+    public function __construct(ObjectManager $om)
+    {
+        $this->em = $om;
+
+        parent::__construct();
+    }
+
+    protected function configure()
+    {
+        $this->setName('vehicle:merge')
+            ->setDescription('Merge duplicate vehicle makes.')
+            ->setHelp('Finds duplicate vehicle makes and merges them into one record. Deletes the duplicate record afterwards.');
+    }
+
+    protected function buildVehicleIndex()
+    {
+        $vindex = [];
+
+        $vehicles = $this->em->getRepository(Vehicle::class)->findAll();
+        foreach ($vehicles as $v)
+        {
+            
+            $mfg_id = $v->getManufacturer()->getID();
+            $clean_make = strtolower(trim($v->getMake()));
+
+            if (!isset($vindex[$mfg_id][$clean_make]))
+                $vindex[$mfg_id][$clean_make] = [];
+
+            $vindex[$mfg_id][$clean_make][] = $v;
+        }
+
+        return $vindex;
+    }
+
+    protected function getDupeModels($source, $vlist, &$found_dupes)
+    {
+        $vfrom = $source->getModelYearFrom();
+        $vto = $source->getModelYearTo();
+        $id = $source->getID();
+
+        $dupes = [];
+
+        foreach ($vlist as $v)
+        {
+            // skip ourselves
+            if ($id == $v->getID())
+                continue;
+
+            // same model years
+            if ($vfrom == $v->getModelYearFrom() && $vto == $v->getModelYearTo())
+            {
+                // mark as duplicate
+                $found_dupes[$v->getID()] = true;
+
+                $dupes[$v->getID()] = $v;
+                /*
+                $dupes[$v->getID()] = [
+                    'id' => $v->getID(),
+                    'make' => $v->getMake(),
+                    'y_from' => $v->getModelYearFrom(),
+                    'y_to' => $v->getModelYearTo(),
+                    'y_formatted' => $v->getModelYearFormatted(),
+                ];
+                */
+            }
+        }
+
+        return $dupes;
+    }
+
+    protected function execute(InputInterface $input, OutputInterface $output)
+    {
+        // get entity manager
+        $em = $this->em;
+
+        // get all vehicle makes
+        $vindex = $this->buildVehicleIndex();
+
+        // collect all dupes
+        $dupes = [];
+        $found_dupes = [];
+        $source_index = [];
+
+        // manufacturers
+        foreach ($vindex as $mfg_id => $vmfgs)
+        {
+            // makes
+            foreach ($vmfgs as $make => $data)
+            {
+                if (count($data) > 1)
+                {
+                    // check if they have the same model years
+                    foreach ($data as $v)
+                    {
+                        // if we already found a dupe with him, skip
+                        if (isset($found_dupes[$v->getID()]))
+                            continue;
+
+                        // get dupes
+                        $v_dupes = $this->getDupeModels($v, $data, $found_dupes);
+                        if (count($v_dupes) > 0)
+                        {
+                            $source_index[$v->getID()] = $v;
+                            $dupes[$v->getID()] = $v_dupes;
+                        }
+                    }
+                }
+            }
+        }
+
+        // process the duplicates
+        foreach ($dupes as $source_id => $sub_dupes)
+        {
+            $source = $source_index[$source_id];
+            $output->writeln('processing - ' . $source_id);
+            $output->writeln('removing duplicates for ' . $source->getManufacturer()->getName() . ' ' . $source->getMake() . ' ' . $source->getModelYearFormatted());
+            foreach ($sub_dupes as $dupe)
+            {
+
+                // move customer vehicles
+                $cvs = $dupe->getCustomerVehicles();
+                foreach ($cvs as $cv)
+                {
+                    $cv->setVehicle($source);
+                    $output->writeln('adjusting customer vehicle ' . $cv->getPlateNumber());
+                }
+
+                // move battery compatibility
+                $batts = $dupe->getBatteries();
+                foreach ($batts as $batt)
+                {
+                    // $source->addBattery($batt);
+                    $batt->addVehicle($source);
+                    $batt->removeVehicle($dupe);
+                    $output->writeln('adding battery ' . $batt->getModel()->getName() . ' ' . $batt->getSize()->getName());
+                }
+
+                // flush
+                $em->flush();
+
+                // remove dupes
+                $output->writeln('removing duplicate - ' . $dupe->getID());
+                $em->remove($dupe);
+                $em->flush();
+            }
+        }
+
+
+        // print_r($dupes);
+    }
+}
diff --git a/src/Entity/Battery.php b/src/Entity/Battery.php
index 4ace13cf..ed0c99ec 100644
--- a/src/Entity/Battery.php
+++ b/src/Entity/Battery.php
@@ -181,7 +181,15 @@ class Battery
 
     public function addVehicle(Vehicle $vehicle)
     {
-        $this->vehicles[$vehicle->getID()] = $vehicle;
+        if (!isset($this->vehicles[$vehicle->getID()]))
+            $this->vehicles[$vehicle->getID()] = $vehicle;
+        return $this;
+    }
+
+    public function removeVehicle(Vehicle $vehicle)
+    {
+        if (isset($this->vehicles[$vehicle->getID()]))
+            unset($this->vehicles[$vehicle->getID()]);
         return $this;
     }
 
diff --git a/src/Entity/CustomerVehicle.php b/src/Entity/CustomerVehicle.php
index 01aff142..3af617ef 100644
--- a/src/Entity/CustomerVehicle.php
+++ b/src/Entity/CustomerVehicle.php
@@ -37,7 +37,7 @@ class CustomerVehicle
 
     // vehicle
     /**
-     * @ORM\ManyToOne(targetEntity="Vehicle", inversedBy="customers")
+     * @ORM\ManyToOne(targetEntity="Vehicle", inversedBy="cust_vehicles")
      * @ORM\JoinColumn(name="vehicle_id", referencedColumnName="id")
      * @Assert\NotBlank()
      */
diff --git a/src/Entity/Vehicle.php b/src/Entity/Vehicle.php
index e7a9a22a..99ec7779 100644
--- a/src/Entity/Vehicle.php
+++ b/src/Entity/Vehicle.php
@@ -24,7 +24,7 @@ class Vehicle
     /**
      * @ORM\OneToMany(targetEntity="CustomerVehicle", mappedBy="vehicle")
      */
-    protected $customers;
+    protected $cust_vehicles;
 
     // manufacturer
     /**
@@ -55,7 +55,7 @@ class Vehicle
 
     // link to batteries compatible with this vehicle
     /**
-     * @ORM\ManyToMany(targetEntity="Battery", mappedBy="vehicles", fetch="EXTRA_LAZY")
+     * @ORM\ManyToMany(targetEntity="Battery", mappedBy="vehicles", indexBy="id", fetch="EXTRA_LAZY")
      */
     protected $batteries;
 
@@ -68,7 +68,7 @@ class Vehicle
 
     public function __construct()
     {
-        $this->customers = new ArrayCollection();
+        $this->cust_vehicles = new ArrayCollection();
         $this->batteries = new ArrayCollection();
 		$this->flag_mobile = true;
     }
@@ -145,7 +145,8 @@ class Vehicle
 
     public function addBattery(Battery $battery)
     {
-        $this->batteries->add($battery);
+        $this->batteries[$battery->getID()] = $battery;
+
         return $this;
     }
 
@@ -170,4 +171,9 @@ class Vehicle
     {
         return $this->flag_mobile;
     }
+
+    public function getCustomerVehicles()
+    {
+        return $this->cust_vehicles;
+    }
 }