Yeah, counterweight shouldn't be too much of a problem. This is at home, so no osha and I won't be lifting too much in the heavy department. I'm just wondering if the batteries will over heat or work for a short time. The 4d battery is intended for boats I think and I'm not sure what the deep cycle version is for, but it is much bigger than a car battery -20" long by 5.5" wide by 10" tall. I don't think car batteries will do the job, but no one seems to know about these larger ones.
Thanks,
Mark