This is the item that makes our systems unique. Installed in your boat's boiler compartment (or close to it), it serves two purposes. It monitors
the battery charge level, and
the water temperature.
If the battery charge level is greater than 80% (user configurable) AND the water temperature is under 40°C but not over 52°C it turns on power supply to either the 12v heating element directly or to the inverter if that system is installed.