? Charging Electric Bike Battery

Are you not going to drive your truck for extended periods of time? If so, then a generator. But if you are driving your truck daily or almost daily, then just put the inverter directly on the batteries. I'd bypass the cig lighter.. but i guess you could start with cig lighter and see if you blow the fuse first.
Seems to be the logical solution. Your daily drive will recharge the battery is no time. It would be almost like free electricity.