Heater core replacement

Post date: Mar 28, 2015 8:35:21 PM

Since there will be no running engine making hot water, and the controller/electric motor do not produce enough heat, there is no way to defrost the windshield. Either we add a separate hot water heater that re-uses the original heater core inside the car, or we put in an electric heater and blow through it with the original fan. The Nissan Leaf uses a reversible heat pump to achieve efficient heating and cooling, but this is a step too far for us.

So, we sourced two 750W 110V ceramic heaters from a Chinese supplier at Aliexpress with the idea to put them inside the original air distribution box:

Heater core substitute, with 2x 750W 110V ceramic heaters

When applying current to the heaters, they keep heating and their resistance falls, increasing the power draw even more, until the bolted-on thermostat interrupts at about 160 C. After one try, one thermostat broke already and stayed open.

Driving the heater core with PWM, using an Arduino running a PI-loop
Heater controls modification, to allow temperature setting of the new heater core
Put a sliding potentiometer in the lever's position
Modified lever, almost the same look as from the factory