[mcginn]

It looks like someone has a similar idea but, i was watching QVC where they had portable jump start batteries for sale. Well my idea is to have a permanent back-up battery built in your car. When your car is running, excess electricity can be sent to it, if needed to keep it charged via a relay. But when the car is off the battery will be disconnected from the car. Then one night you leave your lights on and kill your battery, you simply flick a switch and start your car using the integrated back up battery.

Reward: if used commercially.... a new car and credit.