More on the battery. I have a couple Very Bright "Tuff" LED lights. Ordered a small sealed 12v lead acid battery to power one and test for the other bike and light, before ordering another for like $10.. This tiny battery is only 1.2 ah, yet it kept my LED lit for over 8 hours yesterday! That's plenty for me. Done testing, don't need to run it all the way down and possibly damage it. For a rear light I have a few small cheap lights to choose from that use AA or AAA batteries. I like the one with the lasers that point out parallel lines sort of in the path of the bike, and quite a few flashing patterns to choose from as well.
Oh, back to the battery,
L 3 3/4"+, W 1 5/8"+, and H 2"+. I am so amazed by the battery output, and the light output!
Wiring? Not my specialty. I don't have high hopes unfortunately. Will probably end up with too many zip ties. I'm more of a wham bam, thank you man, It works, I'm done.