A technical inquiry that some of you may have an idea about. I have a 1982 Wide Glide (FXWG). I will soon be attaching a home built 'Sport' sidecar to it, nothing fancy or different about the entire subject at all, but.. instead of the rather pathetic, renew it every year battery, of the correct dimensional size for a Glide etc etc, I thought I might have a rather more decent car battery inside the 'boot' of the chair. Plenty of room there, secure and safe and everything. What I would like to know is what size does anybody recommend. I used to have another outfit many years back with a weird car alternator fitted on frame I made, and belt driven from the sidecar wheel, plus various electrical doo-dads to make it all work alright. I had a rather fetching Bosch battery back then of almost aircraft battery size bolted into the chair behind the rear seat. More modern batteries are far more complex, so any help would be appreciated, thank you..... :Shrug: