forgot to mention: these scrap guys may be a good source of used batts.
they get used 12v truck starting batteries from a local commercial truck service center. he said the trucks usually run 4 batteries, and if one fails, the service center replaces all 4.
oh, and the
scangauge showed 68.2 mpg (us) on the return trip to the scrap yard (about 8 km). i'm liking that engine kill switch.