Thanks Ecruz.
I've thought about the dc-dc converters and have burned up some already. I like to change my lights around my other bikes, so nothing is permanent. Some of my LED's are direct drive and the little DC-DC converters can't deal with the higher current. I drive a pair of xml's straight from 2s 18650's. My brightest flood light is a dual MT-G2 setup and that will require a bigger converter just to run it. I could probably make it work within the space right about the 18s3p 5ah pack, if I went to a permanent light setup.