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Wow, we need to find another way to heat EVs
- Thread starter marco33
- Start date
TomB985
Member
There is the answer!
Rather than getting by burning a few gallons of gas a year, I should burn hundreds because I can't pass the "EV purity test". Gotta love it. The age-old concept of "perfection being the enemy of good". In any case, I can't drive a hybrid because none of them will steer themselves. Unique situation for myself, but that's why I have my 3.
coconutboy84
Member
TomB985
Member
Seriously. I can't. They don't steer themselves yet.
And I can put up with the inconvenience that comes with near double the power consumption in winter. But I don't like it, and would much prefer a better option.
A lot of us BEV owners get all warm and fuzzy about our "we don't emit CO2" cars. The problem is, we do emit CO2. How is the electricity generated that is used to charge your car? Chances are, some sort of fossil fuel was burned to create the energy that is now sitting in your car. Yes, you are reducing the amount of CO2 released into the atmosphere by driving a BEV, but you aren't at zero.
The Superchargers at Price, Utah often have "Powered by Coal" stickers on them. This enrages a lot of Tesla owners, but the simple fact remains that the stickers are correct; the Superchargers there are powered by a very large coal burning electrical generating plant nearby.
So now you're burning fossil fuel, converting it to electricity, charging your car, then using that to heat your car. You're burning fossil fuels to power your car just like an ICE vehicle, you're just emitting less CO2 in the process. Using that electricity to heat your car instead of moving it down the road drastically increases your CO2 emissions; that energy was used to create heat instead of forward motion. This doesn't effect ICE emissions, as waste heat is used to heat the cabin. But in our case, the energy we have can either be converted to forward motion or heat. Just by using your Tesla's cabin heater, you're generating a larger carbon footprint than you would if you didn't use it at all, as once again, that energy is being turned into heat instead of motion.
The point of all this: Don't be so hard on those that suggest some sort of fuel fired cabin heating alternative. Don't kid yourself... unless you're using 100% carbon neutral source of electricity, you are burning fossil fuels to heat your Tesla's cabin. If you generate that heat by burning a fossil fuel or alcohol locally in your car, the electricity that would've been used to generate heat can now be used to move your car down the road.
IMO, the winter range hit simply requires more planning and a bit more time. A trade off that my family happily makes to keep the 3 on the road in the winter.
The Superchargers at Price, Utah often have "Powered by Coal" stickers on them. This enrages a lot of Tesla owners, but the simple fact remains that the stickers are correct; the Superchargers there are powered by a very large coal burning electrical generating plant nearby.
So now you're burning fossil fuel, converting it to electricity, charging your car, then using that to heat your car. You're burning fossil fuels to power your car just like an ICE vehicle, you're just emitting less CO2 in the process. Using that electricity to heat your car instead of moving it down the road drastically increases your CO2 emissions; that energy was used to create heat instead of forward motion. This doesn't effect ICE emissions, as waste heat is used to heat the cabin. But in our case, the energy we have can either be converted to forward motion or heat. Just by using your Tesla's cabin heater, you're generating a larger carbon footprint than you would if you didn't use it at all, as once again, that energy is being turned into heat instead of motion.
The point of all this: Don't be so hard on those that suggest some sort of fuel fired cabin heating alternative. Don't kid yourself... unless you're using 100% carbon neutral source of electricity, you are burning fossil fuels to heat your Tesla's cabin. If you generate that heat by burning a fossil fuel or alcohol locally in your car, the electricity that would've been used to generate heat can now be used to move your car down the road.
IMO, the winter range hit simply requires more planning and a bit more time. A trade off that my family happily makes to keep the 3 on the road in the winter.
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ralph142
Member
TomB985
Member
It would actually be quite a big deal. Mounting and fuel storage would be a huge challenge with the battery placement.
I love my car. Sometimes think about ways it could be better, though. That's all this is... It's got me through the winter so far, and I don't expect that will change.
Daniel in SD
(supervised)
To all the people crapping on the idea of putting a fossil fuel heater in the car, do you all use an electric resistance heater to heat your house? Why not?
Msjulie
Active Member
No because it's terrible for efficiency and Ca title 24 makes it pretty tough
But we are lucky enough to live in a geographic location where heat-pump based systems work just dandyThis is a similar system to what we have Mitsubishi Multi Zone Ductless Mini Splits
Sorry this jumped off heating-in-car but @Daniel in SD asked
My brother tells me that the motors should be generating a substantial amount of heat. I'm sure Tesla has thought of routing the heat into the cabin somehow, but maybe it's not possible or maybe it isn't worth the trouble. Seems like that could reuse some power for heat.
Daniel in SD
(supervised)
I also have a heat pump at home.No because it's terrible for efficiency and Ca title 24 makes it pretty tough
This is a similar system to what we have Mitsubishi Multi Zone Ductless Mini Splits
Sorry this jumped off heating-in-car but @Daniel in SD asked
It seems like the problem with putting a heat pump in the car would be the size. The radiators on efficient heat pumps are pretty large. The cabin heating and cooling requirements on a car are actually about the same as an apartment, 5kW = 17,000BTU.
The biggest problem with a heat pump may just be that it doesn't help EPA range.
They do use the motor heat to warm the battery but the motor is extremely efficient. If it's 95% efficient and drawing 15kW at 60mph then that's 750W of available heat.
Actually, that’s how the Model 3 generates heat... by using the drive motor. The Model S and Model X both have resistive heating elements, but the Model 3 basically vibrates the drive motor to generate heat.
Electric motors are very efficient at turning electricity into rotating force. So much so, that not a lot of heat (when compared to the rotational power produced) is generated. When you use cabin heat in the Model 3, the motor controller causes the motor to generate more heat than it normally would. I’ve been trying to research exactly how this is done, but haven’t found a lot of info on it yet. But basically, you’re tanking the efficiency of the motor’s ability to generate rotational power in order to generate heat that it normally wouldn’t. Supposedly, this is more efficient than the resistive heating elements found in the S and X.
Yes, electric motors do generate some heat when they are generating power, but much less energy is wasted by heat generation in an electric motor than an ICE engine, which is what gives BEV’s a lower carbon footprint than their ICE counterparts even when you burn coal to produce that electricity.
Bjorn Nyland has a YouTube video that shows the power consumption of the drive train when the car is stationary and he turns on the cabin heat. I don’t have the time to find a link for it now, but later today I’ll post a link to it. It’s pretty eye-opening to see how much energy is used by the cabin heater at full blast. He has a device hooked up to his car that shows the power consumption of each component in real time as the car is driven (or parked, as the case may be).
AlanSubie4Life
Efficiency Obsessed Member
That is incorrect. A PTC (positive temperature coefficient) resistive heater of 7kW capacity is used. It is completely separate from the stator heating which is used to warm the coolant loop.
Have to be careful to distinguish stator heating from other draws in such videos. Just because cabin heat causes the stators to start drawing power does not mean that the stator heat is used to warm the cabin directly (though a warm battery does not hurt I am sure); it does not necessarily follow. It is unfortunate that Bjorn’s commentary is such low density information - with all the data he gathers he could be much more succinct and make things more clear for people. The information delivery is so slow and punctuated with so many exclamations of “that’s goood shee—-t” that people kind of lose track. I guess it is part of the charm. I like my information delivered dryly and humorlessly.
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TomB985
Member
Mine draws between 3 to 3.5 kW when preheating the cabin. There’s also a noticeable buzzing coming from the rear end when this happens. Stator temperature of the drive unit increases when this starts, and you can see an increase in the battery inlet temperature as well indicating this heat is going to the battery.
The buzzing and power draw from the rear motor shuts off when I open the door, it doesn’t happen when I am sitting in the car. Just when the cabin is empty for some reason.
The buzzing and power draw from the rear motor shuts off when I open the door, it doesn’t happen when I am sitting in the car. Just when the cabin is empty for some reason.
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AlanSubie4Life
Efficiency Obsessed Member
Yep, your car is drawing 10kW total. 7+~3. Yeah this is how it works. I don’t know when they decide to turn the stator heating on (it appears to turn on when defrosting car, I assume you used that button). But hear a lot of reports that it does not occur when driving unless going to a SuCharger (and of course the sound is obvious). I’m sure the Bjorn videos have all the info. Just not of much significance where I am so don’t follow the details.
I do hear the pump running vigorously when the car is cold and at high SoC, but that is distinct from a stator heat. Some sounds are similar (pump, etc.), but it is not as loud as the stator heat. All the sounds seem to be really distinctive so should not be difficult to work out the details.
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TomB985
Member
I never said car. "Mine" referred to my rear drive unit.
I haven't supercharged much since getting the adapter, so I couldn't say for certain. It doesn't appear to happen while idling with a cold battery at a traffic light, so I don't think the function is active otherwise.
ralph142
Member
TomB985
Member
And more to the topic at hand, I really don't see the electric motors making enough heat to provide any meaningful heat to the cabin with normal operation. It does a downright lousy job heating that 1,000 lb lump of metals and electrolytes underneath the floor, barely hitting 60 or 70° f after an hour drive around 25° F. The secret sauce to Model 3's industryleading efficiency is the motor...
All manufacturers pour large dollars into motor development to wring out as much as possible for each watt going into the motor. That leaves precious little heat waste.
All manufacturers pour large dollars into motor development to wring out as much as possible for each watt going into the motor. That leaves precious little heat waste.
AlanSubie4Life
Efficiency Obsessed Member
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