Packs are run on both hyper 9e's with connections towards the rear. Both ends of the tray are also padded with 1/2" of foam to soften any shock. The crazy thing is the 2 that have gone up in flames so far went up right as soon as I pulled away. Lucky they did really as both times I was close enough to get to them before they went up in flames in the car. The amount of smoke from these cells is also unreal. I couldn't see anything when I was pulling batteries out. I was working blind. When they go up they put out so much heat that they burn away both straps so battery come out pretty easy.