[SlowButSteady]

My boat has two 6V GC batteries (got them at Costco; they have similar specs to T-105s, but I'm under no illusions about them being "as good as" T-105s) as the "main" bank, and a 50 ah "wheelchair" AGM battery (got it at Sears) as the "reserve" bank. Either bank will start the 2gm20, no problem. I normally use the main bank for everything (starting and deep-cycle usage), with the AGM being there "just in case" (but I never really needed it, yet). All the charging inputs (alternator, solar, shore power) are connected to the "main" bank with a battery combiner, that has a AGM setting for the reserve bank, interconnecting the two banks. The access to the batteries on my Cal 2-27 is rather insane, so muscling anything bigger than the golf cart batteries into place would have been out of the question. The capacity of the GC batteries is probably over-kill for my boat. But I NEVER have to seriously worry about draining the batteries too much.