I have moved forward with the battery back up for the shack. I have looked at several different batteries and configurations for this project. I believe that 6v golf cart batteries would be the best route to go, but of course I did not go with conventional wisdom. I went with the Deka DC27 12 volt deep cycle marine battery. These are about 75amp hour batteries. I have 6 of these for the battery box. I went this route because it would be easy to grab a couple to go remote site. Also the price was right. I built a battery box for these with some scrap wood and a pallet for the base. I will post some pictures later. I custom built the connection cables with 2/0 wires. I will also be running some short cables to the new shack I am building. This will let me run 12v items without having to use a power supply connected to the charger/inverter that I am using. The charger/inverter will be for another post.