How much power does the heater use? 600W!

[kirby]

This isn't a controlled experiment, just something I stumbled onto I thought others might like to know:

Unusual for me, but I decided to turn on the climate control yesterday before leaving. I set it for 73F, I don't know garage temp when I did this. Charging was done already, just the heater was running. Before I unplugged, I took a look at my EVSE's screen and it showed a current that varied between 1.5A and 3.1A during few seconds I watched it. The EVSE is plugged into ~243VAC. So that works out to ~360W to 750W of input from the wall. I assume this goes through the same AC->DC power supply that charges the battery, so take maybe 85% of that for efficiency loss and I end up with about 600W on the high end.

This has to be just the resistive heater because the car wasn't running so the heat pump had nothing to do. I don't know if this was when the cabin was already near 73 and therefore is a low or high guesstimate.

 

[vetaldj]

I did turn it few time when driving and available mileage dropped exactly in the half. That thingy likes energy for sure.

Good thing I don't need to use it but I started to feel bad for those who own eGolf in colder states...

 

[nsayer]

A hair dryer is often 1.5 kW, so 600W to heat a whole car is quite efficient, IMHO. I'd be surprised if that wasn't, in fact, the heat pump rather than the resistive heating element. When I precondition the car, there's a whole lot more sound coming from it than just a fan.

 

[miimura]

Since you have a SEL, it's using the heat pump. 600W for a heat pump is about right. I would not be surprised if the LE and SE models that don't have the heat pump could pull up to 3,000 watts. My RAV4 EV has a 6,000W electric resistance water heater to heat the cabin.

 

[kirby]

Since you have a SEL, it's using the heat pump. 600W for a heat pump is about right. I would not be surprised if the LE and SE models that don't have the heat pump could pull up to 3,000 watts. My RAV4 EV has a 6,000W electric resistance water heater to heat the cabin.

(facepalm) I was being stupid. I swear I know what a heat pump is, and the the theory of operation, but for some reason my mental model of my car was that the "heat pump" was pulling heat from batteries and the motor and moving it to the car. Of course, you don't really need a heat pump for that so much as just a fan! In my flawed model, a resistive heater was being used as a backup.

Got it. Yea, miimura that makes sense. I was surprised 600W would do it.

 

[Golfcart]

I've got an SEL and done no measurements at all, but my experience this winter, during cold Bay Area days and nights, is that if I turn the heater on with a full charge my estimated range drops from about 73 miles to about 45 or 50 miles.

That's a pretty big drop right there, and so on cold days I've started turning the heater off and just using the heated seat function.

 

[rjnerd]

Interesting. We have a '15 SEL, and turning on cabin heat is typically a 10% hit. (10 miles drop, tops. Same as summer AC use) And here in New England we get a lot colder than the Bay Area. It's in the low 20's right now...

Hitting the "max defrost" button which uses both the heat pump in AC mode to dehumidify, and a resistive heater (in addition to the wires embedded in the windshield) to warm the air, the range does take a 50% hit. I normally just explicitly turn on the windshield wiring, which is apparently only available from an on-screen menu. The button on the dash with the straight edges is for the rear window, the icon on the menu has curved lines top and bottom to indicate it's the front window.

 

[mfennell]

Interesting. We have a '15 SEL, and turning on cabin heat is typically a 10% hit. (10 miles drop, tops. Same as summer AC use) And here in New England we get a lot colder than the Bay Area. It's in the low 20's right now...

10% is my rough observation too, in temperatures down to the high teens.

Of course that's just the estimate. The only way to really know is to drive it all the way to zero, which noone is going to do.

 

[Jiffy]

FWIW, I have measured the power consumption of the heat pump heater on my 2015 SEL with a power meter at home (Kill-a-Watt) and using the info provided by the ChargePoint EVSE at work.

In both cases the car was fully charged and I was pre-heating the car for my morning or afternoon commute. I'm in MA and we've had some temperatures in the teens and 20s, so I think it was a good test.

Turns out the heater draws about 1,300 Watts for a while, and then tapers down a little (to around 1,000 Watts or so) as the car warms up depending upon the outside temperature.

I knew the heat pump was working well when I was pre-heating the car in my garage, and the temperature actually dropped 2 degrees in the garage in about 20 mins as the heat pump was taking the heat out of the garage and moving it into the car!