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Divert Load FAQ

Frequently Asked Questions

How does the divert load work?

A divert load accepts excess power that a wind generator can produce beyond what the batteries are capable of safely accepting and disperses that extra power as heat. With a charge controller but no diversion load, the excess power would flow to the controller and have nowhere else to go, damaging the controller. The divert load helps to maintain system safety.

Hotwire makes a Resistive Load Bank of ceramic resistors to be used as a diversion load, but the preferred option by far is a dual voltage water heater element. It has two loops in one unit.  One loop (element of heating wire) is made to work on 12 volts at 300 watts, and the other operates on 120 volts at 500 watts.

You can make hot water from the 120 volt side using shore power or a gen set.  Because the 120 volt side is smaller than the original heater element, it will take longer to reheat the water in the tank when all of the hot water has been used, typically 2 to 3 times longer.

The 12 volt side is used to dissipate the excess power from a wind generator or solar panels, and the amount of current going to it is controlled by a diversion type charge controller.  The controller senses battery voltage and diverts current into the water heater when the battery reaches the voltage set point.

One of our customers, who has a lot of solar panels on his boat, uses a switch and turns the 12 volt side on every day after his batteries are full.  In the past, diversion type controllers sent the excess energy to heating coils that turned the power into hot air, a bit the way Hotwire’s Resistive Load Bank works.  With the dual water heater element, you get something useful and don’t heat up the inside of the boat. A distinct advantage in the tropics!