Strange Xantrex Inverter Issue I'm Befuddled

[Twins]

I've had a problem for a while now with my Xantrex Inverter. All lights will be lit showing a full charge, but within 2 days I'll have a red light showing low batteries. Now my befuddlement is I can go into the battery compartment disconnect the batteries and immediately connect it again and everything reads fine on the Xantrex. I've racked my brain for quite some time now to come up with a solution but have no idea what it could be. I keep thinking I'm missing something blatantly obvious. Maybe I'm too close to the forest to see the trees.