Kind of reiterating some things I said in another thread, but, I feel it might work better if the penalty for the battery going dead was less severe. Like instead of being completely unable to use the ATV, let you continue to use it but at reduced functionality. Like have all the bells and whistles run on the battery, like the lights, turbo, any special upgrades like the map or radio, etc, and when it runs out, those stop functioning but don't prevent you from driving. Maybe you could also make it so you have to turn the engine a few times (not sure if that's the correct term) every time you try to start it instead of having it start immediately, or possibly make it so the engine stalls occasionally. But having it be completely non-functional seems a bit much, especially considering that's already the penalty for running out of fuel. As-is the battery just seems like a more expensive second fuel.