I bought a 18v cordless hedge trimmer with 1 hour quick charger for $45 from walmart.
I'm the one that saids to use a cordless drill battery in all the posts(same battery).
so im using the battery,charger,and i cut the handle cradle part off the hedge trimmer for the battery to lock into on my bike. Im using a 12v car clearance light bulb for my headlight and a 12v red trailer dome light for taillight. (lights are hooked together in series to = 24v's. Battery is 2years old works like new keeps lights lit for many hours and is cheap to replace but never had to. The 12 volt car bulbs are cheap to replace to.
I may look for 18v bulbs so i can hook the lights up regular. but if you bought a 12v battery you could hook up the car light bulbs up regular.