I am dumping my Sol-Ark extra power (smart load) into my solar 80 gallon hot water tank (its a hot water tank that feeds from solar hot water roof panels) Tank the elemnet I installed is 3500 watts (thats the max for Sol-ark they said). It a 240 element. That tank had no elements when I put it in years ago. Now its free water heat. Its been a great think to do with any extra power you generate. This tank feeds out 40 gallon natural gas water heater.I also have grundfus smart pump that is recirculating the hot water thru house off the bootom 40 gallon tank drain for instant hot water at all the taps.