I inherited 16 x 100Ah 12V batteries and all the interconnect cabling from a decomissioned IT back-up power solution that we had running at work. The batteries are all in good shape and are rated for PV use. The intent was to have a workshop across the street on an adjacent property to my house. There are no electrical services there now and to establish electrical services would be too much money for my simple use. I want to do a low cost alternative off-grid solution, less than $2000.
I assumed that the 400watt panels would essentially trickle charge the battery bank when not in use, and the generator would supplement the rest of the charging when there was actual heavy battery draw. Leaving the PV panels aside for now, I was assuming I could buy a cheap generator like the Champion Model #76555 3000W GENERATOR; then get an AGS like the Xantrex’ Automatic Generator Start (part#84-2064-00) to start the generator automatically when the battery volt readout was low and stopped the generator when the readout was OK; and finally get a Inverter / Charger like the Nature Power 38326 Pure Sine Wave Inverter with 55-Amp Charger, 2000-watt to hook into the panels and generator. The theory is that this would give me a cheap solution for off-grid power and up to 5 hours of battery power doing standard workshop duties without draining the batteries more than 25% of their capacity. As soon as I reached the low battery threshold the Generator would kick in and recharge/supplement. Alternately, if I was only occasionally using lights and draining the batteries slightly before shutting the workshop off the PV system would trickle charge and replace the lost charge. Therefore, I assumed that I don’t need a lot of panel wattage to keep the system at a good state of charge. I don’t need 240VAC and I won’t exceed a 15amp circuit at any time. PV Panels will go on a separate shingled wood shed near by with full southern exposure (Can be built in any direction needed). I am assuming roof mounted panels.
What do you recommend and what components am I still missing? Is my logic sound?
