I came across this wonderful device from China, it is a 3 functions in one and plugs into a standard cigar lighter 12V socket.
As it turns out I already have a cigar lighter socket (12V outlet) added a couple of years ago to do the Applecross adventure. The temperature sensor is an external thermistor (a resistor that changes impedance with temperature) on a 30mm lead from the unit. If you extend that lead and attach it by araldite to the water system in some way you have a coolant temperature gauge + volt meter that tells you how well the Dynamater is doing and provides a USB connection for charging your phone.
There is one snag I attached the thermistor to the thermostat housing, there is a 25 degree difference between what the thermometer reads and the actual water temperature. so when it reads 55deg C the actual temperature is 80 deg C (the thermostat temperature). When the thermostat closes the water pump runs and maintains a constant temperature in the engine.
Maximum temperature 95deg C |
New thermistor location |
Here is an Index page for the build