Working on my 550 build, I have 300 watts of solar on the roof. My plan was to use 2 GC2 6 volt golf cart batteries. This would give 230 AH of storage. The cost here in Alberta is $185.00 each. I was just at the local farm supply called Peavy Mart and they have a 12 volt Tractor battery that is 360 AH, and is only $240.00. This would sure give me lots of backup starting power for the truck at 1200 cranking amps too. I'm not sure how it would stack up against golf cart batteries for storage though? I do have room for it in my planned battery storage compartment so that's not an issue. Thoughts?