I just accidentally deleted my original comment.
Heres I what I deleted.
There’s a few things a bunch of other commenters are getting wrong, at least from my understanding.
The AC compressor is run by a belt from the engine. Unlike a home AC, a vehicles AC is either on or off. There is no cycling. The temp control is just changing how much outside air comes in, or how much heat is drawn from the engine.
The fan speed is not going to effect anything at all. The alternator spins to generate electricity to recharge the battery, but the amount of energy required to spin it doesn’t change based on how much electricity is being drawn.
Tamping your AC down in any way, whether by lowering fan speed, or increasing the temperature is less efficient. Use it at it’s coldest temp and highest fan speed if you’re going to use it at all.
Edit: I almost forgot to add that AC efficiency is going to be more closely tied to your driving speed and outside air temperature. Driving faster makes your AC more efficient (not necessarily your whole car). More air passing over the evaporators means more heat released from your AC to the outside, which makes colder air in your car. The colder the air outdoors, the more heat the AC can release to the outdoors, which means colder air in your car.
As for EVs, I have entirely no clue, but I would assume it’s a similar situation.
Edit: I may be entirely wrong. I’m not sure about anything anymore. I know a guy who knows all about these things, let me get him down here tomorrow and we can go from there.
A7thStone@lemmy.world 8 months ago
A vehicle AC compressor does cycle. There is a clutch on the pulley attached to the compressed that engages the compressor or lets the pulley free wheel.
ostsjoe@lemmy.world 8 months ago
Also the alternator absolutely takes more power from the engine in proportion to how much energy it’s putting out.