Looking for engine battery info. I have searched different sections and levels of the forum, and of our owner's manual, and can't find info about the recommended engine battery for our 2015 Promaster 3500, converted to an RV. We had a replacement engine battery installed 6/2018 when the original was only 3.5 years old because it wasn't holding a charge. Seemed early. Now the replacement installed 20 months ago dies only 2 weeks after being charged (it is sitting in driveway over the winter in Massachusetts). Shouldn't need replacement. Am wondering if the shop put the wrong battery in it. We have not found a repair shop that knows Promasters anywhere reasonably near; Dodge Ram places do not seem to know anything about Promasters. Its current battery is marked Mopar Group H8 [BBOH8800AC, 800 CCA(SAE), 95Ah; RC150 MINS SAE]. I'm listing all this because I have no idea what it means, or which info a knowledgeable person might want. Any advice will be appreciated.