Does Model Y have a PTC (resistive heater) in addition to the heat pump?

[ratsbew]

How does the heating work for everyone? Is is using PTC to blast a lot of warm air at first and then use the heat pump to sustain on longer journeys?

It seems like the Y's initial energy consumption is quite high during winter which suggests PTC use.

 

[Feathermerchan]

No PTC heater but it can operate the drive units, compressor and cabin fan in an inefficient manner to add more heat to the cabin. So functionally similar and use more energy when everything is cold. We noticed on a long highway trip (two days of 12hr per day) that it used much less energy than my 2018 Model 3 (PTC) to heat the cabin. On a trip, it probably gets heat from the drive unit(s) as they are not 100% efficient. There's probably around 1-2 kW to be had from the inverter and motor.

 

[RiverBrick]

Does the thermopump work when it's -6F?

If not, it must have some other way heating.

(The temperature hit -6F (-20C) or lower at some point during daylight hours everyday in my first January of Model S ownership.)

 

[ratsbew]

That's kind of what I figured, so short trips are still pretty inefficient, but longer highway drives are much more efficient in winter than the older 3s. I'd imagine that supercharging on road trips puts a lot of heat in the battery and probably makes road trips a lot more efficient in the winter since you can rob heat from the warm pack.

 

[Feathermerchan]

Also driving does heat the pack some. Ever notice how the regen dots disappear or reduce after yo drive a while? That's the battery warming up. Overall we have seen very close to the same consumption from the Y and the 3 but in the Y we've been much more liberal with cabin heat. so its more comfortable.

 

[ratsbew]

How does the car handle pre-heating the pack for supercharging in cold weather? I think the heat pump setup has something like 12 modes so it may be able to scavenge heat directly from the motor or something.

I'm a total nerd so I wish there were a diagnostic screen to show the heat pump mode and coolant flow.

 

[Feathermerchan]

The coolant loop can take heat from where it needs to and deliver it where needs to. If navigating to an SC it will run the motors in an inefficient mode to generate the heat necessary to heat the batteries. On our 3 and Y I can hear the motor/invertor making a high pitched whine when in this mode.

 

[glhs272]

<I'm a total nerd so I wish there were a diagnostic screen to show the heat pump mode and coolant flow.

If you are not already aware there is a phone app called Scan my Tesla. The app and bluetooth OBD2 adapter are not too difficult to install. Get's you a lot of info including the ones you mentioned.

 

[ratsbew]

Yep, have it on my 3. The Y will be my wife's car so I doubt I'll go through the hassle of installing it since I won't drive it much.

 

[mark95476]

You already called it, but FYI--
Bjorn said he talked to some Tesla factory guys about the 2021 M3 heatpump and confirmed no PTC heater. It's probably the same for MY.

No PTC heater but it can operate the drive units, compressor and cabin fan in an inefficient manner to add more heat to the cabin. So functionally similar and use more energy when everything is cold. We noticed on a long highway trip (two days of 12hr per day) that it used much less energy than my 2018 Model 3 (PTC) to heat the cabin. On a trip, it probably gets heat from the drive unit(s) as they are not 100% efficient. There's probably around 1-2 kW to be had from the inverter and motor.

 

[ratsbew]

Wow, it's impressive that they thought so far as to run the cabin fan motor in a matter to extract heat. I can't imagine that it adds more than a hundred Watts of heat, but still interesting.

 

[TomServo]

Folks need to watch a few of Bjorn's YouTube video's. Since I haven't purchased the ScanMyTesla gizmo/app I can't really see what's going on but Bjorn shows you how the car is managing battery temps/charging/heating etc. It's pretty amazing to see various components turn on/off. His videos help you understand and manage driving/charging strategies.

 

[WattsappMTL]

Does the thermopump work when it's -6F?

If not, it must have some other way heating.

(The temperature hit -6F (-20C) or lower at some point during daylight hours everyday in my first January of Model S ownership.)

As other posters have indicated, the heat pump system is very sophisticated and starts to draw energy from the battery coolant circuit once the outside air doesn't provide enough heat to maintain cabin temperature. In this situation, you may see the number of regen dots increase as the battery gives up its heat to warm the cabin. However, I have experienced erratic supply of heat once it starts getting cold outside. Even after preheating the cabin when the car has been parked outside for a while, the heat pump sometimes delivers barely warmed air for a while after setting off.

 

[ratsbew]

It's a shame they couldn't have included a backup PTC for brutally cold conditions or even a simple "block heater" to put in the glycol loop. I know they are trying to take out cost and use a "big brain approach", but how much could a 5kW resistive heater cost to put in the glycol loop?

A block heater could be positioned in the glycol loop in such a way that the warm glycol goes to the heat pump's heat exchanger first so that it has a nearly instant source of heat energy. I'd pay the extra $200 to have this.

The problem with the current approach is that there is so much thermal mass in the whole powertrain / battery system that even adding heat from the motor stators takes time. One of the big quality of life things about EVs is instant hot air.

 

[MY-Y]

My MY gets toasty warm very fast. It can dump several KW into the front motor to heat up to get extra cabin heat as needed.

 

[stopcrazypp]

It's a shame they couldn't have included a backup PTC for brutally cold conditions or even a simple "block heater" to put in the glycol loop. I know they are trying to take out cost and use a "big brain approach", but how much could a 5kW resistive heater cost to put in the glycol loop?

A block heater could be positioned in the glycol loop in such a way that the warm glycol goes to the heat pump's heat exchanger first so that it has a nearly instant source of heat energy. I'd pay the extra $200 to have this.

The problem with the current approach is that there is so much thermal mass in the whole powertrain / battery system that even adding heat from the motor stators takes time. One of the big quality of life things about EVs is instant hot air.

The thing is the markets where this would not generate enough heat is small. That means they spent extra money that most people would have no use for. And given they are doing everything to bring costs down, that probably doesn't make sense for the.

 

[Sudsington]

It's a shame they couldn't have included a backup PTC for brutally cold conditions or even a simple "block heater" to put in the glycol loop. I know they are trying to take out cost and use a "big brain approach", but how much could a 5kW resistive heater cost to put in the glycol loop?

A block heater could be positioned in the glycol loop in such a way that the warm glycol goes to the heat pump's heat exchanger first so that it has a nearly instant source of heat energy. I'd pay the extra $200 to have this.

The problem with the current approach is that there is so much thermal mass in the whole powertrain / battery system that even adding heat from the motor stators takes time. One of the big quality of life things about EVs is instant hot air.

They use the compressor and 12 V cabin heater for this exact scenario (ambient temp < -10C or 14F and little to no heat available from battery or motors). It takes place of a resistive heater, as the electricity put into running the compressor results in 100% equivalent heat energy output. A really good breakdown of the heat pump system's modes here: Tesla Model Y Heat Pump Details Infrequently Discussed By The Media. Modes 2-5 deal with extreme cold.

 

[Sudsington]

As other posters have indicated, the heat pump system is very sophisticated and starts to draw energy from the battery coolant circuit once the outside air doesn't provide enough heat to maintain cabin temperature. In this situation, you may see the number of regen dots increase as the battery gives up its heat to warm the cabin. However, I have experienced erratic supply of heat once it starts getting cold outside. Even after preheating the cabin when the car has been parked outside for a while, the heat pump sometimes delivers barely warmed air for a while after setting off.

I've read that people have had issues with their ambient temperature sensors. You should ask your local service center to run a remote diagnostic on your temperature sensors.

https://www.reddit.com/r/teslamotor...utm\_source=share&utm\_medium=web2x&context=3 https://www.reddit.com/r/teslamotor...utm\_source=share&utm\_medium=web2x&context=3

 

[DonaldBecker]

Wow, it's impressive that they thought so far as to run the cabin fan motor in a matter to extract heat. I can't imagine that it adds more than a hundred Watts of heat, but still interesting.

My BMW e39 has a 40 amp blower fan fuse, suggesting that it's using 200-300 watt at full power. Presumably they designed it to be efficient. An intentionally less efficient motor (e.g. operating a brushless motor with delayed phase) might be able to double that.

 

[MY-Y]

QUOTE="DonaldBecker, post: 5325548, member: 142973"]My BMW e39 has a 40 amp blower fan fuse, suggesting that it's using 200-300 watt at full power. Presumably they designed it to be efficient. An intentionally less efficient motor (e.g. operating a brushless motor with delayed phase) might be able to double that.[/QUOTE]

I'm not a Tesla HVAC expert, but from what I've read... Heat can be intentionally created in the stator of the front drive motor (not sure how this works with RWD). It can create several KW of heat when energized in a certain way. This is done when it is more efficient than scavenging heat from the outside air or from the battery. In a sense, they have a massive resistive heater in the MY; it also happens to be the front motor. Like Elon, I'm pretty impressed with the design.