It's quite easy to generate heat in brushless motors. It's designing a motor controller to be efficient and thus generate less heat that is the challenge. The only reason to do it with the HVAC fan motor is that the system doesn't need to heat the large external mass of the integrated drive modules.
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Does Model Y have a PTC (resistive heater) in addition to the heat pump?
- Thread starter ratsbew
- Start date
It's quite easy to generate heat in brushless motors. It's designing a motor controller to be efficient and thus generate less heat that is the challenge. The only reason to do it with the HVAC fan motor is that the system doesn't need to heat the large external mass of the integrated drive modules.
sleepydoc
Well-Known Member
Here in Minneapolis we just finished a cold snap where it didn’t get above zero for several days. It was -27 the other day when I woke up. A heat pump as the sole heater in this case just doesn’t cut it. I don’t know what other mechanisms the Model Y uses but I can definitely say they were inadequate and the cabin temp never really got above 30-40º. Now that the temps are warmer (up to 18º F today!) The cabin heats much better, so I know the heat pump is functional.
You can say that the number of markets where a auxiliary resistive heater is needed is small, but if you’re going to sell cars in the upper Midwest, then you need to sell them with adequate heat. How would people in TX or AZ like it if the A/C couldn’t drop the temp more than 15º?
You can say that the number of markets where a auxiliary resistive heater is needed is small, but if you’re going to sell cars in the upper Midwest, then you need to sell them with adequate heat. How would people in TX or AZ like it if the A/C couldn’t drop the temp more than 15º?
You should take it to a service center. They may replace the compressor or temp sensors. It should (and does usually) function at those extremely cold temperatures.
https://www.reddit.com/r/teslamotors/comments/lenrht/2021\_m3lr\_heat\_pump\_stopped\_working/gmpavdr?utm\_source=share&utm\_medium=web2x&context=3 https://www.reddit.com/r/teslamotors/comments/lenrht/2021\_m3lr\_heat\_pump\_stopped\_working/gmpimtf?utm\_source=share&utm\_medium=web2x&context=3
I think the cheapest solution would be a "block heater" in the glycol loop. It puts heat into the whole system and the octovalve setup can put that heat wherever it's needed to include in the cabin. It would be a "easy" fix that could even be retrofit if it's simply put in-line with an existing coolant line.
jeffpaz
Member
Agreed. I live in MSP as well, and my Y was a delightful 72 degrees inside each day after 5 minutes of preheating.
This is literally what the car does with the front and rear stators. Each produce up to 3.5 kW of heat into the “whole system.” 7 kW of heat is a LOT of heat. If the car cannot stay warm, there’s something else going on. When the car is in full on create heat mode, it uses close to 11kW in all. I assume that is the stators, the heat pump, the blower, the radiator fan, and the seat warmers.
sleepydoc
Well-Known Member
I'll have them check it out. Now that it's warmer it works fine but when it was below 0 the air coming out of the vents never got above what I would call 'cool.' I'm pretty warm blooded, so I was fine driving the car, but it definitely wasn't heating the cabin.
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