I just installed an automatic transfer switch which i have my fridge connected to so now I can run my fridge on solar power
and when it run low on solar power then it operates on utility power automatically. I have four sets of harbor freight 180 watts and 0ne 70 watt panel = 250 watt - five deep cycle batteries - 3000 watt inverter - one doc wattson energy monitor - 25 amp meter - and a black and decker power monitor. The name of the company for the transfer switch is tekris, check out their website. Cost with shipping was $182.00 and its easy to install. Everything just plugs in i hooked up a timer on the utility side of the transfer switch to turn the utility power on and off to simulate utility power going out so the inverter goes on and then i set the timer to a off time when i think my solar power will run down and then it switches back to utility power. Any questions ask.