I followed Jon's suggestion, did an equalization, made sure to set dip switches correctly. This was all quite easy to do. Batteries are still not lasting very long, though we are in some extreme temperatures right now, so I think my plumbing bay heater has been running constantly, which is a pretty good draw. I suspect I have a bad battery somewhere. Since Marathon charged me two arms and a leg for the batteries and installation, I may have a chat with them. The batteries are only a year old. That just seems too young to die.

Jon, do I understand correctly.... if one battery is bad, the whole bunch is spoiled? Yikes. That's an expensive fix.

Thanks to everybody for the help!

Adam