Does any one out there in cyberspace have any experience/advice about using a dual voltage 12vdc and 115vac water heater element for their onboard heater? Some background. I am installing 2 115 watt solar panels with two victron MPPT 75 15 smart controllers. Each panel goes to each controller, operating independently of each other. Each controller has a load output that can be programmed via bluetooth. According to Victron the load can be a water heater element. Basically, once the batteries (four T105 trojans deep cycle wired in series parallel for 450 amps) are charged the control output shifts from the batteries to the load output hopefully heating the water. There is also a 100 watt panel on the dodger goes to a gensun mppt controller that goes directly to the trojans and to the start battery via an ACR. The load output voltages (cut in and cut out) will have to be programmed in consultation with Rolls Battery company. The heater element will be powered from the excess power from the solar panels, not the batteries. Apologies for the long background for a simple question, however I am trying to foresee any reasonable basic questions that might be asked. Thanks to all and I look forward to a good discussion.