I just can’t seem to pass up anything free. I somehow decided that my 2 deep discharge batteries weren’t enough backup for my furnace. They were disposing of the UPS system at work which still had 4 years left on the nominal 10 year batteries. So I took 18 of them and the racking system and set them up downstairs next to the furnace. Each battery is 2 cells of 2 volts, so when you hook them up in series you get a 4 volt 300 Amp/hr battery. So the 18 batteries give me six 12 volt banks for a total of 1800 Amp/hr. This coupled with a 600 watt pure sine inverter and relay setup from Xantrex and I should be able to go for a couple of days. One thing I did noticed is when I went to charge them, the charger would hang up at 85% for hours. If I turn it off and back on, it jumps to 95%. Eventually it will show 100% and I get the green light. Just for fun I plugged the furnace into it the other day and let it run for 40 hours. The only thing calling for heat was the hot tub, and I fired the boiler for about 8 hours to bring the storage up to 175 for DHW. According to the Kill-o-watt meter I used a little over 2000 watts and the voltage never dropped below 12.5. There are front panels and a top that I attached after I hooked everything up. A nice neat and clean setup. . BTW a friend took the other 120 batteries and hooked them up to his solar panels at his cabin in Vermont.