hey RapidRoy this is the version I currently use for all my 12v charging needs
Battery tender Jr.
gets the job done and won't break the bank. charges my car battery from nearly dead to full over night (12 hrs =/-) 7ah SLA in around 8 hours from nearly dead.
Hark you may want to look into motercyle/golf cart batterys pretty much the same power but a lot less weight. If I see you at Flloyd I'll show you my setup. can't miss me just listen for the music coming out of my pit box.