EV HVAC - is the heating and a/c one system

[Simon_GH]

Out of interest, is the heat pump circuit in an EV the same as the a/c cooling system just running in reverse?

What prompted my question was the recommendation to run a/c systems regularly in cars to keep the seals oiled etc. and I wondered whether using the heat pump does the same job.

[GeniusOfLove]

If it's an EV with a heat pump then yes your assumption is correct.

Not all of them use heat pumps and have some sort of resistive electric heater and conventional AC for cooling, with an electric compressor.

[Simon_GH]

Appreciated - thank you. Ours happens to be a heat pump model which piqued my interest.

[mikey_b]

Simon_GH said:

Out of interest, is the heat pump circuit in an EV the same as the a/c cooling system just running in reverse?

What prompted my question was the recommendation to run a/c systems regularly in cars to keep the seals oiled etc. and I wondered whether using the heat pump does the same job.

Broadly yes, but it's a bit more complex than that. For example, it will at different times need to independently heat the battery, heat the cabin, cool the battery, cool the motors, or cool the cabin. Sometimes it will need to heat one thing and cool another at the same time, in which case it operates in heat pump mode to remove heat from where it's too hot, and then takes it to wherever isn't hot enough. If everything is too cold, it will use a electrical resistive heater to strongly warm the coolant and thus everything else. And if everything is too hot, it will operate more like a standard cooling system, pumping coolant around to remove heat and then sending it to the radiator and fan, to dump the heat to the air.

For many years now, I just set the temp to 20C and leave it on Auto. These systems work more than well enough to keep me comfortable these days, and an EV is no different.