- The LEAF’s heating system is similar to that of a vehicle with an internal combustion engine except for the source of the heat. An internal combustion engine generates heat which is extracted by coolant (water and antifreeze). The hot coolant then circulates through a coolant-to-air heat exchanger known as a “heater core“. A fan, ducts, and valves direct the air where it is desired. Excess heat is dissipated by the coolant circulating through a radiator. The LEAF differs in that the coolant is heated by a resistive element Interwiki: CN++ which produces only the heat required, so there is never any excess heat to send to a radiator. Because the coolant does not circulate through an engine or radiator, the volume of the coolant used is much smaller (only 1 7/8 quarts , page 9-2).
- The heater runs if the fan is on and the selected temperature is higher than the ambient temperature.
- evseupgrade.com offers a modified climate control unit (in trade for your stock one) that will have the heater come on only when the climate control is on, and/or the rear defroster is on, and/or the climate control timer engages. (evseupgrade.com is the same outfit that customizes the OEM Nissan EVSE to also work on 240V.)
You remove and send in your stock climate control unit (video instructions here) and they send back a modified climate control unit.
- When in ECO mode, the climate control system operates at decreased capacity to reduce power consumption Nissan LEAF Service Manual, page HAC-23; also , page 4-12.
- Diagram of outlets and air mix ratios of various settings of climate control “MODE” button:
Diagram of ventilation duct and its doors, and a table of door positions for various settings of climate control “MODE” button:
- A sun-load sensor Nissan LEAF Service Manual, page HAC-137 on the dash also provides input to the automatic climate control unit:
“When the sunload suddenly changes, for example when entering and leaving a tunnel, correction is performed so that the recognized sunload of the A/C auto amp. (“amplifier”) changes slowly.” Nissan LEAF Service Manual, page HAC-15