Thanks for all the helpful replys that have been given. To the issue that my coach is supposed to have four GC batts well the rack/drawer would hold them but mine never had them. Original paint on the floor of the drawer unscratched or worn where a batt would have lodged
I looked around locally where we are staying and there is some old stock sitting on shelves or more accurately angled racks that probably leave some of the plates in the batteries high and dry. Could not find matching date codes for our 31 group engine batteries and AGM GC batts are not stocked.Sams club had a wild variety of date codes and said they cant get more of the same until existing stock is sold. So once they break a pair they will never sell a matching pair again
Napa states that group 31 batts are sold in pairs only that is for the starting batteries. So if you know what you want you will probably have to order it as MH stuff is not important to retailers.
Went to Batteries + Bulbs and ordered 2 AGM 31 Starting batts and 2 Marine/deepcycle 31 group AGM for the coach. The date codes are supposed to match.Bought the X2 brand which is 100% lead and supposed to be a quality product. The starting batts are 60 month and the M/DC are 48 month full replacement. Thinking again about pairing maybe the warranty does not make sence as you would break a pair if you replaced one.
I got my desired cranking amps from coach batts that start the generator and will have matching charge profiles for the engine and coach that charge together; whenever the engine is running, the generator is running, or we are plugged into shore power. Also the batteries will accept the higher charge rate that our Intellipower 9180 can put out in the short amount of time allowed for generator operation while dry camping with restrictrions. So we are going against conventional wisdom here and spending a lot more dough to do it but hopefully I have thought this through properly and all will work well. Thanks again for your guidance. Dennis