Yep, even 18 *cheap* 12v batteries will cost you another $2000 and that is still not including the charger. Even if you came up with all that, where/how are you going to charge 18 12v batteries? It would take days with a standard 120v charging system. Lastly, 18 12v batteries will only get you a very (very) short distance between each recharge.
The weight of 18-36 batteries is more than the van itself. Another 3000-4000 pounds in just batteries... on top of the weight of the chassis. Wow.
This van is a novelty. Something that you might use to show off, but not as a practical vehicle. For the $5000 (minimum) that it would cost to purchase and buy batteries, you could get a much better gasoline powered van without all the headaches.