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Houseboat Hot Water System
Designed by Mark Little
Hot Water System Controller Construction
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The Hot Water System Inverter controller is mounted in a battery compartment that also holds the houseboat's batteries. Although the compartment is fairly well sealed, it is not totally waterproof, so in rough conditions, some water can enter the compartment. To protect against the rare condition, the controller is mounted in a waterproof case.

To allow the lights on the Arduino and the daughter board to be easily seen, the case has a transparent lid. This allows the easy monitoring of the system to diagnose any issues that may arise. The lid need to be removed to access the mode switch and the setting potentiometers.
The current sensor and the inverter control relay is mounted on a daughter board attached to the Arduino. There are three (3) pairs of terminals on the controller assembly.
Connector Set Function
12V Power This pair of terminals are used to connect the +12V battery supply to the controller.
Pump Motor This pair of terminals is used to connect the Hot Water pump to the controller.
Inverter Power This pair of terminals is used to connect the inverter to the controller.
This terminal configuration provides an easy way to bypass the controller should it fail. If the controller fails to operate, the cables from the Inverter can be placed on the 12V power terminals, and it will operate continuously. This will use more power, but if necessary, to save power, the inverter can be turned off and on via the switch on the inverter.

Should the current sensor fail, the pump motor cables would also need to be shifted to the +12V terminals. As an alternative, the case can be opened and the sensor bridged out of the pump circuit with the link provided in the case. The operation of the pump will be as normal.