Yeah, those are pretty bad. Should never have passed QC. Whoever signed off on that has some 'splaining to do.
I’m extremely leery of heat pumps because of days like today -35C, -48C windchill - I know windchill doesn’t affect the car per se but it surely affects me if stranded and would result in faster cabin heat loss when parked. Or have they sorted that? I know a year or two ago there were a bunch of reports of Model 3’s with heat pumps failing to heat in extreme cold conditions.
Yeah, we should be worried about heat pumps here. But when it’s warmer they are more efficient.
I haven’t head of any Tesla heat pump failures in a couple of years, and all of their models have them now. They did have some early issues that they addressed with firmware updates. The heat pump does get less efficient at colder temps, but it should still work. In the absolute worst case, it acts as a resistive heater by operating the motors in an inefficient regime.
So Tesla has an electeic heat backup? I believe heat pumps for homes in Canada have to have electric heaters as backup for when it gets too cold for the heat pump to function, which is around -24 or so as I recall. So in really cold weather, suddenly natural gas heat switches to electric heat. It does this when the grid is already under stress due to demand and loss of wind/solar in winter.
So if Tesla has the capability to heat electrically, is it roughly as efficient as other vehicles with electric heaters, or is it an expensive backup source that isn’t very efficient but keeps you from freezing?
It’s not a dedicated backup. The entire thermal system is interconnected, though, so they can intentionally run the motors hotter to put heat into the rest of the system. Imagine the case where the motor is stopped: you can just turn on all the windings, without sequencing them, and you’ll just get a lot of heat out from the resistance. The same basic idea works in motion, too.
It should be roughly as efficient as a normal resistive heater. They’re all about the same.
It somehow transfers heat to the interior through a heat exchanger or something? Or is this just to keep the battery and electronics warm?
Yes, every part of the car that can emit or receive heat is connected to the same system (through the octovalve). So waste heat from the motors can be moved to the cabin, or from the cabin to the battery, or basically any other combination.
Here’s a schematic of the Model Y system:
It does show a low-voltage heater, but whatever that is, it’s too small to be particularly effective.
I haven’t read this–only the media summaries of it–but this is the patent that describes all the modes and ways of moving heat around:
That’s reassuring, because honestly those earlier reports were terrifying. This winter up till now has been exceptionally mild, so this sudden cold snap has caught us all un-acclimatized and jeez was I freaking cold even though it warmed all the way up from -35 this morning to -34 in the afternoon. Obviously in these sorts of temps reliable heat is literally life and death, so you’ll find people here absolutely without compromise on the issue.
That is a very clever design.
Yeah, while it’s hard to be absolutely sure that they’ve solved all of the issues, given the massive number of heatpump systems they’ve sold around the globe, and the lack of any recent reports on problems (and let’s just say, there’s no shortage of media scrutiny on Tesla), I think it’s probably a non-issue at this point.
If my understanding is right, the waste heat actually goes to the cold side of the heat pump. Suppose that it only works down to -25 C, but it’s -35 C. Then, the resistive portion only needs to bring the coolant up 10 C, and the heat pump can handle the rest. So it should still get only progressively less efficient (and still be better than pure resistive).
Either that or the whole factory has been under the gun to get some vehicles out the door so they can claim success.
So the QC inspector said “This one still sucks, but frankly they all still suck”. And then the Head Honcho said "Elon said we must ship and ship we shall. I approve this one. And the next five dozen as well, sight unseen. "
Sandy Munroe has brought it up as an example of something that’s virtually impossible at traditional automakers due to the established company divisions. There’s a group that handled the engine cooling, and another the cabin cooling… how do you get one fully integrated system out of it? You can’t achieve that if groups are engaged in power struggles about who gets to do what.
Maybe that’s overstating the case a bit, and other automakers will figure it out eventually, but Tesla was the first to have a unified system like this.
I wonder if another possibility is that the panel was detached during transit. But if so, that wouldn’t give me the warm fuzzies about quality either.
Excellent point. It sure looks like whatever pins or clips hold it on just pulled out. Like a loose peice of 1970s chrome trim.
I have a Model Y and this is my 4th Saskatchewan winter. The heat pump has been fine in all conditions. The battery, of course, takes a beating, but the heat pump was able to keep up. The only time my windows got frosty was when my two dogs were in the back seat after a run.
Is the heat pump backed by electric resistive heat for really cold temps? I can’t imagine a heat pump doing much at -35. If so, I’d imagine the tesla is efficient in cold down to wherever the heat pump has to be augmented, then rakes another range hit.
Still better than relying on resistive heat all the time, though.
I’m not sure. All I know is it was warm enough. There’s nothing on the display that would show it, to my knowledge.
Plenty of heat available from the seat heaters, too.