Aug 25, 2014
gavine We need a heater on/off button, similar to the AC on/off. I picked-up my car in May so I haven't spent a winter in it yet. The other day, it was 70-degrees (F) but humid in the early evening. I turned the AC on to take the humidity edge off, but with the temp set at 70-degrees, I felt a little chilly so I turned it up to 73. Doing that caused the heater to turn-on. I know this because I could smell it. The heater had never been used so it had a burning type of smell. As soon as it turned it back down to 70, the smell went away.
Why would the heat turn-on when the AC is on and it is 70-degrees outside? If that's a general preference, okay, fine, but I'd like to be able to override that. I just wanted to minimize the AC, not turn the heat on.
If there were an on/off/auto button for heat, that would be great. Auto for the masses and on/off for someone like me who wants to be able to control it.
If it were an ICE, I wouldn't care, but since the heat uses a lot of electricity from the battery, I don't want it turning-on without my knowledge. Once the smell burns-off, I won't even know the heat is running....which brings up another request, there should be an indicator on the screen telling you when the heater is running. Even if an on/off is not possible for some reason, at least the indicator would warn you to lower the temp until it turns off.
Am I the only one who cares about this? I searched but couldn't find any discussions about it.�
Aug 25, 2014
cinergi There isn't one -- I think most of us override the fan speed to achieve what you're looking to do.�
Aug 25, 2014
scaesare I'm not sure what else the car should do if you instruct it to provide you with warmer air than ambient?�
Aug 25, 2014
ItsNotAboutTheMoney Ambient was 70F.
You told the car you wanted the temperature to be 73F.
How is it going to achieve an increase in air temperature of 3F?
So what you really want is a de-humidify only setting?�
Aug 25, 2014
GaryREM I guess I can understand why some people would want to be able to control every aspect of things.
But, I'm not sure what the need is from a practical standpoint. What is your concern?
Energy usage? I suspect that is insignificant.
I'm one of the masses who want's less things to think about when driving. I leave everything on auto unless driving with roof open and windows down. Let the system decide what to do and only adjust temp as needed.�
Aug 25, 2014
gavine So what if I just want the fan on and no AC or heat? How do I know what temperature to set so as to not use the heater. Energy usage is part of the reason I want this. I feel like the heater and AC should BOTH have an on/off setting. Why does the AC have one but not the heat? If you want everything automatic than the AC should be fully auto too with no option to turn it off.
The heater energy usage is NOT insignificant. It uses much more than the AC does.�
Aug 25, 2014
mgboyes Does it? How do we know? How much is "much more"?
I know that there's a direct heating element used to fast-start the heating in the cabin (mine came on this morning for the first time since I've owned the car, and there was a brief smell of burning dust that passed within 60s), but mostly the cabin is heated or cooled by the same heat pump that runs the AC, isn't it? I.e. it can run in either heating or cooling mode, and its power consumption is likely to be pretty similar either way.
If you want the cabin to be 73F, set the temperature to 73F.
If you want to use less power, put the car in range mode.
Then sit back and enjoy the ride...�
Aug 25, 2014
Doug_G Dial it all the way down, you will see LO instead of a temperature indication. You won't get heat.
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Yes, but the amount of energy used depends greatly on the situation. If the car is cold soaked then it has to use the resistive heaters. If the drive train is warm, though, it uses that as a reservoir for the heat pump, and cabin heating power usage goes down dramatically - closer to 1 kW instead of up to 6 kW. So once you've been driving it for a while the energy usage drops dramatically.
This is a huge improvement on the Roadster, which only has a resistive heater. It's amazing that the Model S can heat a much larger cabin with much less energy.�
Aug 25, 2014
scaesare
This. If you have the A/C, you just get ambient air provided you DON'T have the windshield vents enabled. :cursing:
Yes, the S excess heat from the motor/inverter in the coolant loop to provide cabin heat... but does it do that by running the A/C subsystem a a heat pump? The service diagnostic screen for the thermal management system simply refers to it as a "chiller"...�
Aug 25, 2014
gavine But, with the AC on to remove humidity, I will get frozen-out because on "LO", the AC compressor is at full tilt. Here's the thing, if I use the AC for humidity-only, the car shouldn't run the heat and the AC at the same time, especially if it's 70-degrees F outside. Just because I turn it up 2 or 3 degrees doesn't mean the resistive heater should turn-on. I just want AC for humidity but turn the temp-up to keep AC at a minimum. I don't want to use the heater in the summer.
Maybe there should be an outside temperature threshold before the heat turns-on. Better yet, give me a heater on/off button and problem solved. "Auto" for the masses on/off for those who don't want AC and heat running at the same time.
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Or how about this? The AC has Auto, On and Off. With the AC set to on, no heat. If in "auto", then let it heat as it does now automatically. That would be an easy way to override the auto heat because essentially, you're putting the AC in a strict on-mode. I actually tested that to see if it was the case....it wasn't.
Like I said originally, if on/off for heater is not an option, I'd like to have an indicator telling me that the heater is on so I can turn the temp down until it turns-off. So those who want everything auto, no harm/no foul. For those who care, we can know that we are wasting power with the heater.�
Aug 25, 2014
ElSupreme But the AC has to drop the temperature of the air to pull the humidity out. That is actually how the humidity control works. (Air conditioning - Wikipedia, the free encyclopedia). So for it to remove humidity it has to cool the air. If you want ambient air you have to heat it back up. Which is why your heater kicks back on, so you don't get cold blasted.�
Aug 25, 2014
gavine I understand all of that but I would still like the option to be able to turn-off the heater if I want. I didn't want the heater to come-on the other day and I wouldn't have even known it was on had it not been for the smell.
Everyone's comments make sense and this is a good discussion but being able to turn it off at my discretion or at least being notified that it's on are good ideas I think. These "features/capabilities" won't hinder the system for those who don't care. It would be an option that needed to be manually forced or, if not an on/off option, the notification that it's on would give me the knowledge to turn the temp down a little to make it turn-off.
If I'm on a long trip and it's not cold enough for heat but I accidentally set the temp a little too high, it's going to eat-into my range and I should be forewarned about that so I can compensate.
I have to assume that most owners would adjust the temp down if a "heater-on" icon displayed, especially with the air conditioner on and 70-degrees F outside. I know I would rather turn down to 72 from 73 so as to avoid the heater penalty.�
Aug 25, 2014
santana338 I'm on gavine's side on this one. I don't have any idea when the cabin heater kicks in (or out) and I would like to know so I can make changes (like setting range mode or not) before I get too far into a trip and find out I have less range than I thought. It bothered me last winter a little but it was not a big deal then. I'm getting more used to the systems in the car now and I'd like to be more efficient this winter for better range/faster recharge.�
Aug 25, 2014
ken830 Temp = LO, A/C = Off, Fan-Speed = Manual is the easiest way, and works really well.
If you leave the vent selection (face/feet) in Auto mode, the icon will tell you when the heater kicks on. A/C will be on when blowing at the face-only. Heater is on when blowing at the feet only. Both are on (I'm guessing) when both vents are selected.�
Aug 25, 2014
gavine Thanks santana. I guess we 40 and 60 owners care more about this than the 85 owners and rightly so.
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That makes sense, but I needed the AC on to reduce humidity. Otherwise, this wouldn't have been an issue because I would have kept the temperature down. The only reason I turned it up a little was because the AC was making me too cold since it wasn't really hot outside and I had just turned it on so the AC compressor was going-strong. I was hoping the 3 degree increase would just lighten the compressor power instead of keeping that cranking and then pumping heat to balance it.
Plus, your idea is a hack way. Don't get me wrong, it's fine, but I still think there needs to be a way to override the auto stuff on the heat, just like you can on the AC and other settings. Why leave the heater out of that feature set?�
Aug 25, 2014
ken830 For the humidity problem, just manually turn the A/C on and off as needed. This is no different than the traditional car with no automatic climate control. Think about a regular car -- if you don't want heat, you turn the red/blue dial all the way to blue. And the A/C is usually a toggle button. I don't see a difference. LO = heater off, just like any cheapo car.
I wanted a heat-off button before too, but that was over a year-and-a-half ago and now I just don't see the need anymore.�
Aug 27, 2014
mmh I have to agree with gavine on this. Right now the outside temps are perfect. there's been several times I want to just have fresh air blown into the car and the car turns on the heater. I don't want heat.... I just want air. I don't want A/C. It's kind of silly that the A/C will turn itself on even if set to off to dehumidify the car, if I set it off, I WANT IT OFF.
For those of you saying "I don't want to think about it". Fine, set it to auto and don't think. But for the rest of us, we should be able to control our cars.
Hmm, I guess If it pisses you off enough I could put a physical switch inline with Fuse 20 in Box 1... There's an idea.�
Aug 27, 2014
ElSupreme Uh ... there is an AC off button. I've been successful using it. Turn AC off, temp to max cold and monkey with the fan. Works fine. There isn't an equivalent 'heat off' button which was the gripe.�
Aug 27, 2014
mmh The car will turn the A/C On even when set to off. I get the gripe with heat too, It's annoying the car doesn't obey me with any regards to climate control and just does whatever it wants.
See this thread: AC is ON even when selected to OFF?
�
Aug 27, 2014
scaesare I agree with the general idea of "honor my override of any auto settings".
Historically there has never been a separate on/off button for the heater because, unlike with the A/C compressor, there was no unit to "turn on"... the heat was simply a byproduct of the engine and you could blend warm air in to the system with the temp control.
Hence, to get outside fresh air you disabled the A/C, set the vents to non-recirc, and set the temp to low.
I'd be happy if the Tesla allowed the same. Having a discrete button for hieat would be OK too, but would be a bit redundant as long as the system honored the above manual configuration.�
Aug 27, 2014
Great Dane I Have an P85 and completely agree with gavine
sometimes in the morning you need just a little ac
so like a thermostat in the house you should be able to set it
at 76 degrees so it would cycle the compressor when needed
and would also increase your range by not having the compressor on all
the time
I actually build a electric cycler for my ice
Because it would keep the compressor running
when you adjusted the stupid air duct temp control
that would just mix in hot air from the engine
it worked perfect
12 seconds on 30 seconds off
or 12 seconds on 60 seconds off
giving nice temp control and improving millage
and for an electric car this is very important
its actually worse because the compressor will run
and the strips will kick in and sucking down your battery
go ahead plug your car in don't set to charge. turn on climate and
and watch amp draw from outlet on your charge display
we need a software switch for heat or ac !
�
Aug 28, 2014
gavine Thanks guys. I was starting to think I was crazy for asking for this based on the first round of replies. I was just figuring they weren't getting it. I'm so glad you agree. I feel much better now.
In the end, if Tesla won't give us an on/off for the heater, at least give an indicator on the display saying when the heat is running. This way, I can adjust the temperature down until it shuts off. That would be good enough for me. If it weren't for the smell, I would never know it was on and that's wrong. As was mentioned earlier, the heat in a gas-powered car is just there but with an electric car, a lot of power is being used for it when I don't necessarily want or need it.
Also, the suggestions about putting the temp on low with the AC off and adjusting the fan manually is okay, but not if I need the AC for humidity. When you put temp on LO with the AC on, the AC compressor runs at full-blast and freezes you out, especially at night. I want to be able to run the AC compressor at it's lowest setting (just for humidity) and not blend heat with it.�
Aug 29, 2014
rlang59 This is only the case when the resistive heater is going when the car has not gotten up to temperature yet. After that the heat from the drive train is used.�
Aug 29, 2014
scaesare Ah, good point. Makes sense.�
Aug 29, 2014
trils0n I live in California, so I don't use the heat much, but I think I remember from last winter that the border around the temperature numbers at the bottom of the dash turns red when then heater is on.�
Aug 29, 2014
ruby110 I agree with gavine. I wanted fresh air when the outside temp was 60 and "lo" is 63, I think. I was concerned that I would get heat and I didn't want the energy loss. I hope the resistive heat isn't used much but then I don't understand why Tesla says to use the seat warmers to reduce heater usage.
BTW, I asked my DS about how to turn off the heat and he didn't know so he contacted the service staff. They haven't responded and it's been days.�
Aug 29, 2014
ken830 Did you not see this? Or is this not good enough?
�
Aug 29, 2014
brkaus Not really for/against... But a standard house thermostat typically has off/heat/cool/auto and sometimes fan as options. That to me would be better than a special heat on/off button.�
Aug 29, 2014
gavine I tried it, but I didn't see any indicator for the heater. Where is it displayed and what does it look like?�
Aug 30, 2014
AmpedRealtor LO is low, not 63. When set to LO and A/C off, the climate control system is off with the exception of the fan and is delivering air untouched.�
Aug 30, 2014
scaesare Not if you select the windshield vents.�
Aug 30, 2014
jerry33 Isn't that the same with every modern car? If you select the defrost vents, a/c kicks on to reduce fogging.�
Aug 30, 2014
rlang59 All of the ones I've been in recently have does this.�
Sep 2, 2014
ken830 Sorry. I might not have been clear enough. I'm referring to the vent selection icon:
Assuming the vent selection is left on "Auto", The arrow will point to the "head" when A/C is on. The arrow will point to the "foot" when heater is on. If both arrows are displayed, then it's probably blending both A/C and heat.
You can try this out by adjusting the temp 1-degree at a time up and down and you should see this behavior.�
Sep 2, 2014
ThosEM Perhaps the actual need is for a dehumidifier mode? Then the heat pump would run in AC mode, but the waste heat would be sent to the cabin instead of to the outside, more than nullifying the air cooling effect but retaining the extraction of water from the air. The amount of heat delivered would be quite small, just as it is for a dehumidifier operated in a home. In ICE cars this is often done in the most wasteful way possible, by using waste heat from the engine to nullify the air conditioning and warm the cabin slightly even when AC is running.�
Sep 2, 2014
gavine I get it now. Thanks for clarifying. This will do for now but I still hope Tesla addresses this concern in a future update release.�
Sep 3, 2014
ElSupreme I am not 100% familiar with the HVAC setup the Model S has. I am not even 100% sure it is using the AC as a heat pump, as I have seen no proof of this (I have not been looking for it either).
But using the AC as a dehumidifier requires a large portion of the wast heat to be recovered. And you need physical heat exchanger routing in place to achieve this. Or some other waste heat stream to re-heat the air. Maybe I'll dig into my car and see how the HVAC is setup, or someone else can chime in on the details.�
Sep 3, 2014
ruby110 @AR: Thanks for the clarification. Untouched air is what I was looking for.�
Sep 3, 2014
Great Dane Thank you so much Ken830 for posting the picture that was exactly what we needed
so now we can at least see what is going on with the HVAC system in the car
always learning more about the car. Heat 76 off 77 on in my case
depending on temps outside of course.
ElSupreme according to me it is straight heat strips, for heat not a heat pump
I bet next generation might do it because a heat pump is so much more efficient�
Sep 3, 2014
ThosEM I'm certain the Model S uses a reversible heat pump for both AC and heat, with a resistance heater as an auxiliary to the heat pump when it is below freezing outside. So it has heat exchangers for both the interior air and the exterior air, just like a residential heat pump system.
Having just bought/installed a couple of dehumidifiers, I realized that they are nothing but heat pumps for which the heat exchanger is inside the room being conditioned, basically a refrigerator that just cools air momentarily, long enough to condense out water, then rewarms the cooled air with the same heat it pumped out of it, plus the motor heat, and sends it back to the room. Operating either a refrigerator or a dehumidifier produces a net energy input to the room because there is no other place to which to pump the heat. In AC/heat mode, the heat gets pumped from inside/outside the car to outside/inside the car. So a dehumidification mode would just require that the exterior heat exchanger be switched to interior air flow.�
Sep 3, 2014
AmpedRealtor If that's true, you should hear the compressor running when the heat is on. I don't believe that is the case.�
Sep 4, 2014
ElSupreme Yes those dehumidifiers have two Heat exchanger sections. The cooling section where the expanded refrigerant is used to cool/condense the air, then it is compressed and used in a separate heat exchanger to reheat the same air.
A heat pump/AC unit only has one heat exchanger section, and changes the flow through it from compressed/expanded to change whether it is cooled or not. And a separate heat exchanger in a different air space to remove/add heat.
And I am with Amped Realtor I haven't seen proof that the Tesla is using the AC as a heat pump. I know it is being thrown around as known but it isn't in any specs or been confirmed.�
Sep 4, 2014
jerry33 I don't know for sure either, but you might have to listen very carefully because it's variable speed and it might only be running a minimum speed when defogging happens.�
Sep 15, 2014
gavine Apparently both AC & Heat kick-on with defrost. Yesterday, I smelled the heater again and looked down to see if it was on feet and I noticed that I had accidentally hit the windshield defrost button just prior. I guess Tesla decided that the AC and heat together will defrost better. Just another reason to have an indicator telling when the heat is on. Had I not smelled it, I wouldn't have known the defrost (and heater) was on.�
Sep 15, 2014
mknox This is how ICE cars work also. On an ICE, the heat is always there in the heater core, so if it's cool out, some heat will be coming into the cabin, then if you turn your defrosters on, the a/c compressor will start.
I can see the value of a heat on/off button myself. Tesla is trying to mimic how an ICE car's HVAC works, but there is a critical difference. ICE engines generate so much heat that a lot of complex plumbing and hardware goes in to simply throwing it overboard. It makes no difference if there is heat in the cars heater core. Just deflect the air flow away from it if you don't want any in the cabin. ICE car air conditioners, on the other hand, have a switch. Why not just let the a/c run all the time too, and regulate it by directing the air flow? Because the a/c is a draw on the engine and has a fuel efficiency penalty.
Well on an EV, your electric heat does have a fuel efficiency penalty just like a/c. So for that reason, a discrete switch is not a bad idea.�
Sep 15, 2014
gavine You crystalized my thoughts exactly. There's an AC on/off button, why not heat?. Like you said, trying to mimic ICE but since it has a power draw, it should be optional. If/when we ever get this "feature", I will brag to everyone that it was my idea.
�
Sep 15, 2014
ThosEM Tesla seems to be quiet on the subject of how the climate control system works, but Teslatap is pretty forthcoming.
Model S Top Features | TeslaTap
It would be pretty sad if Tesla had failed to implement a reversible heat pump, because resistance heating is much more expensive than heat pump heat. One of the functions of the energy saving "Range" mode is that it blocks out the resistance heat, limiting cabin heating to the capacity of the heat pump, which may be a bit thin in sub-freezing weather.
�
Sep 15, 2014
ecarfan The Roadster manual also recommends that for defrost the AC and heat should both be on.�
Sep 15, 2014
ThosEM Ventilation Too
I'd also like to see a single button "Ventilate" button, that in one push would turn off AC (including heat), turn on external airflow, set all the vents to open, and turn the fan up about halfway. Any of those could clearly be overridden, but this would be a very handy feature when one finds oneself fiddling with the controls to deal with a cool but sunny day on the superhighway where one just needs airflow to keep the car comfortable without opening up windows to highway noise. It might be called the "Green" button for its relative lack of energy use.�
Sep 15, 2014
gavine Good to know....thanks for the tip.�
Sep 15, 2014
Canuck +1 -- I really want this. I'd prefer if the fan could be controlled, and turned off, so that just the movement of the can bring in the fresh air. Driving through the mountains a lot, this is all that's often needed and breathing that fresh mountain air, with no ICE motor it has to flow over, would sure be nice!�
Sep 15, 2014
rlang59 This is not correct. I had the car in Range all winter last year and it most definitely used the resistance heater. What it does limit is the pack resistance heater.�
Sep 15, 2014
Knobby I'd like to be able to turn off the heat too. Now that it is cool in the morning, I want the fan on for ventilation, but the heat insists on coming on. To defeat the heater I have to set the temp to Lo, AC off, and then fan speed to what I want. How cumbersome. But it is nice that I can put the fan speed on the right thumbwheel, like that a lot. As for the heater maybe I just need to set it to 20 and forget it. I guess that's the intent.�
Sep 16, 2014
mknox Not on my car it doesn't. I get resistance heating right from the get go in freezing temps... just not as much of it. I believe it does stop heating to the battery pack (unless it gets extremely cold).�
Sep 16, 2014
scaesare TeslaTap makes the claim briefly on the "Features" page, but doesn't seem to document it on their other pages, nor refer to any source.
I'm not entirely sure this claim is true... and as mentioned below enabling range mode does not preclude resistive heat being enabled...�
Sep 16, 2014
AmpedRealtor There is absolutely no evidence to support this. Here's an easy way to check for yourself. Crank up the heat, step outside of your car, and tell me if you can hear the compressor ramping up. If it's a reversible heat pump design, both heat and and AC will require the compressor to fire up. Did you hear the compressor?
No.�
Oct 7, 2014
ThosEM I can't claim to be certain of this yet. But I can explain your result. If you crank the heat way up, the system may not run both the heat pump and the resistance heat. Try just activating the heat a bit.
I don't hear much difference between heat and AC, so this seems inconclusive to me so far. I'll be very disappointed if Telsa doesn't use the compressor for heat also.�
Aug 19, 2015
Ingineer There is no heat pump in the Model S, only A/C. The heating in the cabin is exclusively from a 6-7kW PTC resistance heater. There is also no path for using waste heat from the powertrain or electronics to heat the cabin. (Though it can heat the battery)
Tesla could (should) have added a reversing valve and controllable expansion valves to allow heat pump capability, the cost would have been negligible, and it would be 2-3 times more efficient at heating.
The battery can be cooled by a second circuit in the A/C running though a heat exchanger and it can be heated by it's own resistance heater as well.
I agree that when the A/C is manually shut off it should not run either the heater or the A/C (vent only). Since most people don't understand that the A/C is needed for defroster dehumidification, it should continue to enable the A/C system when in defrost mode regardless of A/C mode setting.
Nissan made these same mistakes in the LEAF in 2011-2012. They listened to us in 2013 and added the heat-pump capability and a way to disable the heat.�
Aug 20, 2015
Canuck Thanks for educating me. I've been giving people unintentionally false information.�
Aug 20, 2015
Ingineer No prob, it's crazy to think that a car this otherwise well-thought-out and this pricey would skimp on the marginal cost a true heat-pump would add. I thought for sure if Nissan added it to their EV's, Tesla would see this and follow, but so far they haven't.�
Aug 20, 2015
Dborn a dehumidifier mode is what is required. Likely, though, it will use both heating and cooling modes to achieve your set temperature depending on ambient conditions. At least, that is what happens with conventional air conditioners.�
Aug 20, 2015
mknox I still need to get back to Tesla on this, but was very clearly told when I specifically asked that the electric heater that heats the battery (via the liquid coolant) can also extract heat from the battery, motor and inverter and use it to supplement cabin heat via a "heater core" similar to what an ICE would use on its cooling system. No heat pump, and this would have nothing to do with the cooling system. The way the system works and the way the energy draw tapers as the car warms up sure seems to support this over 3 very cold winters I've been through. My car is extremely frugal with its heating energy consumption compared to several Leaf owners I know.�
Aug 20, 2015
Ingineer Whomever "clearly told" you this is mistaken. The hardware simply isn't there to do what you claim, it doesn't exist, period.
These are facts of which I am 100% sure of:
1. There is an electric battery coolant heater. This can use high-voltage to heat the pack via way of the glycol loop.
2. There is an electric PTC cabin heater which uses high-voltage to directly heat the air in the cabin.
3. There is a glycol to R-134A heat exchanger that lets the A/C compressor also cool the battery glycol loop. This is optionally selectable by valving and a refrigerant solenoid.
4. There is a cabin R-134A evaporator that can cool the cabin air. This too can be shut off by solenoid if only glycol cooling is wanted by the system.
5. There are no other lines into the cabin. The glycol loop does not enter it, and it's easy to see this with a casual look under the frunk cowling. This would be needed for what you claim and it simply doesn't exist.�
Aug 20, 2015
mknox This is disappointing to hear (i.e. that I was mislead), because I spent considerable time back in 2011/2012 discussing this with Tesla representatives when they came to my area to show the Alpha car and later the Beta prototype. Living in an area with very cold winters, it was high on my priority list to understand. A small consolation, I suppose, is that it seems to act as if it's harvesting heat because after about 30 minutes in well below freezing temps, I can drive for hours at summer-like Wh/mi values, even if I stop for a coffee and the cabin cools right down. I only see the huge power numbers upon initial startup if the whole car is completely cold-soaked. Short trips in the winter are brutal on range, however.�
Aug 20, 2015
Ingineer It's possible that the Alpha cars might have had a different system, but the ones we drive are as I stated.
Keep in mind, that the battery has a lot of thermal mass, so if it's being heated in the winter, then it would take a long time to cool off. The act of driving (or charging) may be enough to keep the pack warm once it's up to temp. The pack was way more thermal mass than the cabin, so it's probably this that's eating the most energy.
Ideally you schedule your charge so it just finishes before you are ready to depart in the morning, and you turn on your HVAC about 30 mins before you leave. This way you use less pack energy heating the pack/cabin and you'll benefit from longer range.�
Aug 20, 2015
omarsultan Add me to the list of folks that would like a simple vent button that brings in outside air unchanged--here in NorCal, much of the year, I would be happy if I could simply pipe in the outside air, leaving the car the discretion to dehumidify as it thought appropriate to reduce the risk of mushrooms sprouting in inconvenient spots.�
Aug 21, 2015
mknox Yeah, the thermal mass of the battery makes sense in my scenario of park for a few minutes, continue and see no huge energy draw. I went back to my notes from when I was researching this and unfortunately didn't jot down the names of the individuals I spoke to. It's possible, but I feel highly unlikely, that early cars and/or cars destined for "cold climates" have a different setup.
Yes, I do schedule the charge to complete just before I leave, and usually turn on the HVAC via the mobile app just before I jump in the shower in the morning (in winter).�
Aug 21, 2015
dhanson865 I'd be nice if the arrows changed color
white for fan only (unheated, uncooled air)
blue for AC (dark blue when compressor is on, light blue when selected but not currently drawing extra power)
red for heat (dark red when heat is on, light red when selected but not currently drawing extra power)
blue top and red bottom for mixed (or maybe a blue line and red triangle?)�
Nov 13, 2015
W0QR Blowing Hot and Cold | Tesla Motors�
Nov 13, 2015
Jaff Like this idea of colour coding...you should submit it to Tesla for consideration!�
Nov 14, 2015
supratachophobia We have this suggestion currently entered and up for votes over here: Vote on software features/bugs to fix in 7.1 and beyond
Please vote and let Tesla know what you want.�
Nov 14, 2015
JenniferQ I'm not sure this is the same issue, but sometimes I want just the fan on and not the compressor, so I turn the a/c off but keep the fan on. It then shows "custom" instead of "auto" in the ac dialogue. So it can blow the 68-70 degree outside air through but doesn't run the compressor. That won't help with humidity issues though.�
Nov 17, 2015
gavine And, depending on the outside temperature, it might engage the heater which is why a heater button is needed. Why is there an AC on/off, but not a heater on/off? Back to the original post, in an ICE, the heat is "free" so no need to turn it on/off but on an EV, heat is "expensive" so you should be able to disengage it.�
Nov 17, 2015
garygid If the lowest temperature settings included a setting called "OFF",
used to keep the heater Off, that might be sufficidnt, right?�
Nov 17, 2015
dhanson865 That'd be great. On some cars they drop to "Max Cool" after the lowest temp. It'd be nice if the next stop was "OFF".
60F
Max Cool
Off
or
60F
Off
either way you'd have control over the heat/air by turning it to the extreme of the temp range plus one or two notches to get to OFF.�
Nov 29, 2015
dhanson865 I trust your word. I just thought you might want to weigh in on this post.
Tesla Patent Outlines Sensible Approach to Cabin Heating�
Nov 29, 2015
Ingineer Just because they filed a patent doesn't mean they use it currently. (or ever)
I can assure you that the Model S isn't set up as described in the article.
Here is a picture from the diagnostic menu on the Model S showing the schematic of the actual system:
While there is no way to use drivetrain waste heat to warm the cabin, they can use it to warm the pack when it's cold. The only source of heat for the cabin is the PTC heater. (besides the seat heaters and the people themselves)
The Tesla drivetrain is so efficient there isn't much waste heat anyway, and definitely not enough to heat the cabin comfortably anyway.�
Nov 29, 2015
dhanson865 agreed I just thought it'd save a few steps in the loop/cycle if you refuted it directly now vs me posting there and someone asking you refute it later after even more confusion had time to sow.�
Nov 29, 2015
lucy ok, guess I'm missing something...
I was dinking around with the fan speeds and the temps, trying to get the fan off and just use the seat and steering wheel heaters (best thing evah!!!) in these relatively mild fall days. Could get the temp to "LO" and fan to "1", not satisfactory.
Then, purely by accident, I must have double touched the "climate" icon, and it went grey and the fan shut off. I am calling this good. Seat/steering wheel heaters remained toasty. Good enough until it gets really cold (below freezing). Is this a new feature? Seems like OFF to me...�
Nov 30, 2015
kirkbauer Perhaps a dumb question but how do you vent fresh air without the fan, a/c, or heat on?�
Nov 30, 2015
dhanson865 by driving forward.
Car pushes through air, some air goes around the car but some enters the vents by way of the grill - air ducts - cabin path.�
Nov 30, 2015
kirkbauer I'll try to pay attention to that. In most cars the recirculate/fresh-air option can be modified independent of turning the climate control on or off, but in the Tesla it isn't clear that it is possible.�
Dec 1, 2015
mknox I know we went over this previously where I reported that a Tesla engineer told me they were harvesting waste battery and electronics heat to warm the cabin. This was right around the time the Alpha cars were out, prior to general production. I wonder now if they intended to (based on the patent) but scaled back due to cost considerations? It seems to be a prevalent hypothesis as illustrated from this clip out of the article, and I believe Tesla was "unofficially" telling people it worked this way early on:
�
Dec 3, 2015
Ingineer Definitely possible. I would guess they found that when it's cold, the waste heat is better used to heat the battery pack (which it can). Also, since there really isn't much of it (it's very efficient!), it wasn't worth the cost.
The only things that can cool/heat in the HVAC assembly are the A/C evaporator (this can only cool/dehumidify), and the PTC electric resistance heater. There is no glycol system in there whatseover, which is what would be needed for this.�
Dec 3, 2015
David99 We need to let go of the idea that we need to manually control every aspect of the car to make it efficient.
If I was hypermiling because of fear not making it to the next charging spot, I might want to switch everything off that isn't absolutely needed. But that happens maybe once a year. For every other case, I want to have a comfortable ride and enjoy it. I don't care if the heater will use 4% more energy in the first 10 min and that I lost 7 miles of range. I always have enough range left and I set the temperature to whatever feel comfortable to me. I leave it up to Tesla to make it happen in an efficient way. For what we know, that's exactly what happens. The car is very smart about using different methods to heat and cool the car and switches intelligently between those. No need for us to do all of that manually.
At least that's how I think of driving.�
Dec 3, 2015
jerry33 I've found that for climate control efficiency, the computer can do a better job than I can. The reason is that it can concentrate on the correct temperature level. It's different for moving the vehicle. Automated controls always accelerate and decelerate way too fast for efficiency. They also can't anticipate hills and stops.�
Dec 3, 2015
dhanson865 automated climate control can't anticipate hills (shadows) and stops in sunlight. Automated climate controls are always geared towards the whiners that say it doesn't cool or heat fast enough instead of being tuned for efficiency.
You have a point, I'm just saying it applies to the other side as well.�
Dec 4, 2015
mknox While I agree with the sentiment, the fact is that the automatic HVAC, in it's current form, is just not working. My Model S has never been as good as past cars I've owned with automatic HVAC systems, but v7 has just broken everything, plain and simple.
It's not a matter of efficiency, but one of safety and comfort. If I just leave it on Auto, my windows will quite frequently fog over, and it takes a long time to warm up the cabin. Then when it does, the temperature will start dropping to uncomfortable levels. If I adjust the Fresh/Recirculate, Vent Controls and Fan Speed manually, I can keep some semblance of comfort and prevent window fogging completely. And I do have to start bumping the temperature controls from an initial 72 F setting to about 78 F after a half hour or so just to keep the cabin temperature constant.�
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