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Don't want heater on, want vent
beachmiles
Member
I was looking into something like that, I think the CAN bus is slow enough for a simple switch. Ive ordered some sample connectors from hirshman that appear to be the same.
4way 1.2 SealStar FA Connector
4way 1.2 SealStar MA Connector
I'm looking forward to your findings. I'm admittedly hesitant to disable the heater if I will then be battling the AC freezing over and having to manually address that. Really seems super inefficient if Tesla users the heater to reduce AC output. Seriously inefficient.
beachmiles
Member
Posted the link on Reddit only to get savagly attracted. Please upvote if you get a chance,
Disable the cabin heater in the M3 by unplugging the CAN connector to the cabin heater : TeslaModel3
Disable the cabin heater in the M3 by unplugging the CAN connector to the cabin heater : TeslaModel3
On top of all of this - I want to be retain auto fan mode with AC off... Loved having that in my Audi - I don't need AC in the winter but i want to fan to auto regulate depending on the temperature (which can be pretty mild in the Bay during the winter months).
They don't use heat to reduce the AC output. The compressor is variable output and can be ramped down to almost nothing if that's what the cooling demand calls for. Tesla does use subcooling + electric reheat to provide better dehumidification performance in some weather conditions, which is an energy intensive process.
More info on HVAC dehumidification strategies:
https://www.energy.gov/sites/prod/files/2015/11/f27/fupwg_fall2015_duncan.pdf
https://www.ashrae.org/File Library/Conferences/Specialty Conferences/2018 Building Performance Analysis Conference and SimBuild/Papers/C105.pdf
There are more efficient dehumidification options - like adding a condenser coil downstream of the evaporator coil, but those add system complexity. Tesla decided to reducing complexity at the expense of energy consumption.
x t2m x
Member
I agree with you on using the 'Auto' setting and fo'get about it.
beachmiles
Member
For me constantly burning 1000-2000 watts to heat the car when it's hot outside and average humidity is a waste of energy even if I was plugged into the wall with unlimited range. If youre living off the grid with solar then it's all good, otherwise please turn off lights when you leave the house as Greta Thunberg would say.
But burning 1000-2000 watts heating the car when it's 90 degrees outside while unplugged & running off a battery is worse. Especially for people like me with no home/workplace charging and a 80mi commute.
I’m pretty sure it doesn’t add heat at 90F ambient temps. I’ve only noticed it adding heat in below 60-65 ... maybe around 70 if it’s really rainy and wet, but that’s just going by feeling, not watching actual data.
Note to self: ask for Scan My Tesla for Christmas.
beachmiles
Member
I am looking to get a can setup for scan my Tesla, but in the meantime my DC current clamp meter does not tell lies clamping directly to the power line to the cabin heater. Here is some video evidence, but anyone can pop the side panel and verify my results. It's jumping between 1-1.6kW in this case.
With the scan my Tesla they are seeing higher numbers but close.
Any way to disable heat in Model 3? - Tesla Owners Online
Candleflame
Active Member
we have had some discussions in the australian tesla forum with some measurements and this does not seem to be completely true. The AC is incredibly inefficient at low cooling. something isn't right when the aircon doesn't use that much less electricity at i.e. 28 degrees compared to 40 degrees... In fact, a lot of the saving in consumption just comes from the reduction in the fan speed.
If you use the command "Turn the heat off" it will respond with "Disabling heater".
A button would be good too.
PS: If you say "Disable heater" it says "I don't understand".
A button would be good too.
PS: If you say "Disable heater" it says "I don't understand".
gavine
Petrol Head turned EV Enthusiast
The Hyundai Kona Electric has a heater button and an AC button. With neither of those depressed, it is fan-only no matter what the temperature setting. If you feel cold, you can hit the heater button. If you feel hot, you can hit the AC button....simple.
Candleflame
Active Member
i dont quite believe that unless its a cooling button.
Air conditioning is not the same as cooling. Particularly in humid climates you will quickly learn that cooling the air alone is not sufficient.
My Chevy Volt had a fan only option that I used all the time. I assume the Hyundai could be similar.
Candleflame
Active Member
i doubt that as its not really possible. i.e. if you drive in the tropics at 28C the car will AC the air down to like 18C but then needs to heat the air back up to 22C or whatever you have it set as.
It was/is possible. And I used it often.
If I wanted only fresh air, and no heat or AC, it would do that. Very very occasionally when it was cooling the battery I could tell the air coming into the cabin was slightly cooler. And you could tell by the energy consumption chart on the dashboard if it was heating or cooling.
Candleflame
Active Member
thats just not how air conditioning works. If you drive at 26C in darwin the air will be cooled down to like 18C and dehumidified but would then have to be heated back up to 22C. How are you going to heat the air back up?
Sorry, there must be something missing in our discussion.
You could have heat, or ac, or only outside air. If you used the Fan Only option, that 26° air would come inside the vehicle at 26°. No AC compressor running.
Also, I live in a desert, so fan only was a feasible option when humidity is in the low teens.
You’re correct that in moderate temperature, high humidity conditions, a system that prioritizes comfort over efficiency will cool the air to dehumidify it, then reheat it so as to not overcool the cabin. Teslas do this.
Vehicles with a heat toggle/button will sacrifice occupant comfort in exchange for better range - at least when the driver disables heating. They’ll ramp the compressor down to maintain a comfortable temperature, but in doing so, they don’t dehumidify as well due to the higher evaporator temperature. The evaporator surface temperature must be below the dew point in order for it to dehumidify.
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