The heart of an off grid system is the battery bank. It needs to be sized properly to handle your expected electrical loads between recharge times. Green-Trust runs on a 675ah battery pack consisting of six Trojan T105's, but for the budget minded, the Walmart Type 27 DeepCycle would also work. At $53 each for a 115ah 12v battery, 10 units would make a nice sized pack at 1150ah. This would give you a useful 575ah of power before needing to recharge. A good charger is critical to the health of your batteries, as well as not discharging more than 50%. One charger we recommend is the Vector 40amp charger
. This is a bit undersized for our theoretical 1150ah pack, but is ideal for our 675ah pack. Since we run our VeggieGen
more than 8 hours a day, it's sufficient to do a full recharge of our batteries for overnight use. Our 90 watt PV array puts about 22ah's daily into the pack as well.