A little back ground on the coach. We have owned it less than a year. It has never started cold without the Boost switch. When we bought the coach, it had recently had the inverter replaced, the prior owner said that after that, the chassis batteries would no longer stay charged. So after I got it home and doing some investigation I found that the combiner (magnum ME-SBC) wasn't wired correctly, so after correcting that issue, the chassis batteries are now being charged and maintained. My next step was to take the batteries down to get tested, I figured they were probably bad due to lack of charging (about a year), well they told me that they were fine. I've looked thru the Magnum chassis manual, CAT manual and owner manual and have not found any reference to the CCA required for this engine. Is there any other place I should look? I'm not confident that the batteries are fine either, could be one bad cell but I'm not convinced they are bad either. The batteries are only 2 years old. Anyways, long story. Thanks for the input.