Quite a while ago, when we increased our battery capacity by replacing the single 12v group 27 battery in front of the passenger side rear wheel with two GC 6 volts, we also wired up the starting battery and frig so we can run the frig off the starting battery when we want to. The idea was that we could turn off all the 12v in the coach, to get rid of the parasitic losses, when we were off doing something away from the van. Since a group 27 battery fits in the Chevy battery tray, we figured we would use the Trojan SCS200 group 27 that we took out of the coach system. We also had an old, old Exide group 27 marine starting battery that came with the van, but was pretty tired, and decided to use that one up first. It had 95AH, the Trojan has 115AH, so compared to the OEM starter battery at 60AH, we could use about 35AH and get a day of frig running out of it, and two days when we went to the Trojan.
Since then, we have found if any battery is going to get abused and run dead, or overcharged, it is the starter battery, for lots of good and bad reasons. For that reason, I decided to save the Trojan for a spare for the one group 27 we still have in place, and get a cheaper battery for the starter battery. Why waste a good one if we mess up and kill it dead?
Here is where it gets weird. I figured I would just get a marine starting battery to have the better starting current if needed, and went off to Walmart and Costco to see what they had. Walmart was as expected, $77, no AH rating as it is a starting battery so they don't have to, 50 pounds. Costco was $86, 115AH rating, 57 pounds.
The 115AH of the Costco is equal AH to the much more expensive Trojan, and the weight is even pretty close (57 vs 60#), so it is reasonable they could actually be getting that much. Really odd they could get it in a starting battery, however. Longer warranty than Trojan, too, at 12/30 months.
I bought one to try out and see how it goes. Checked at 12.65 volts when I got it home with 5 cells at 1265 and one at 1255. I put it on the 3 step charger to charge and then will equalize to see how it turns out.
If they are durable, that is a lot of capacity for not much $$$.
Anybody ever use the 12852 27-DC Costco battery?