Any new battery should be fully charged when you get it home and given an overcharge if the SG is not up to spec. (it was sitting on a shelf getting stratified) that will be your "baseline SG" as the target SG for future recharges.
I don't know of any "break-in" requirements.
What is the model number of the new 31s?
The truck camper we got recently had an older 12v NAPA 31 in it as its battery, and I can't find it exactly on the NAPA site. (nearest seems to be a starting battery with 1000 or so CCA). Some of the labels are gone or unreadable. It weighs about 56 lbs so not that heavy for its size.
It says "HD Commercial" on it and has wafer cell plugs flush with the top and they have screw-driver slots in them to unscrew them to get at the cells.
I am wondering if it has any deep cycling ability or if it is just a starting battery. Its SG is on the line between fair and good, so it still works.
