Indeed which is part of the goal, you want warm batteries, low viscosity oil, and cold electronics. The system would need to cycle the coolant valve to regulate.
It isn't a great system, but really simple and fairly low cost.
It isn't a great system, but really simple and fairly low cost.
Lon12
Member
I don't think the model 3 has much waste heat from the drive units. When I'm driving in cold weather at highway speed I can leave the supercharger at 50ºC battery temperature. Once I'm on the highway the pack cools almost one degree per minute until its sitting below 30ºC. Not active cooling, just from air flow around the car. Coolant at or below 30ºC doesn't leave much to heat the cabin with.
Almost wish I could put a battery blanket on the bottom so that it wouldn't cool so much between Supercharging sessions.
Almost wish I could put a battery blanket on the bottom so that it wouldn't cool so much between Supercharging sessions.
Yeah, the pack is big radiator and the 3 is efficient. Are the drive units at the same temp also?
30C would still heat 0C fresh outdoor air. Even 86 F would impart some energy to the cabin air before a PTC.
I'm looking forward to seeing what they came up with.
What part of Norway? Oslo' is warmer than Green Bay WI, so is Trondheim which is farther north sure you know that but most of us on this side of the Atlantic are not familiar.I live in Norway so worse off than you tempwise
You are right, I thought green bay was comparable to Trondheim. We live some hours north of Trondheim, more inland. Slightly colder than Værnes where I live so I guess most winters you have a bit colder temps than us. Average january temp is 24F/-4.5C (-11-+2C) according to local weatherdata.
I drive Nissan Leaf with and without heat pump and Kia Soul with heat pump as company cars, and efficiency is far better in winter than Model S. Drove 110km in 0C 2 days ago in Kua Soul with 4 people in car, climate at 67F. Draw to hvac was 0.5kW average (0-1.2) all trip (it was preheated). Model S usually stays at 1.5-2-kW all trip under same circumstances. Leaf without heat pump is very similar. Below - 5C there is little advantage to HP and they mostly rely on ptc heaters.
When I use my home charger (12kW) regenlimit disappears after charging for 1-2 hours, meaning batterytemp of 16C+ at same temps. Driving for and hour increases temp quite a bit more. Tested with short precharge last weekend. Started with 30kW regen, which is 12C I think, after 30 mins of driving I had full regen meaning temp was 16C+ this was with range mode so battery heater is not active, only passive heating. If we had hvac connected to coolant loop it would mean that heat from driving could help heat interior after 45mins of driving since I prefer 18C interior temp when driving.
I drive Nissan Leaf with and without heat pump and Kia Soul with heat pump as company cars, and efficiency is far better in winter than Model S. Drove 110km in 0C 2 days ago in Kua Soul with 4 people in car, climate at 67F. Draw to hvac was 0.5kW average (0-1.2) all trip (it was preheated). Model S usually stays at 1.5-2-kW all trip under same circumstances. Leaf without heat pump is very similar. Below - 5C there is little advantage to HP and they mostly rely on ptc heaters.
When I use my home charger (12kW) regenlimit disappears after charging for 1-2 hours, meaning batterytemp of 16C+ at same temps. Driving for and hour increases temp quite a bit more. Tested with short precharge last weekend. Started with 30kW regen, which is 12C I think, after 30 mins of driving I had full regen meaning temp was 16C+ this was with range mode so battery heater is not active, only passive heating. If we had hvac connected to coolant loop it would mean that heat from driving could help heat interior after 45mins of driving since I prefer 18C interior temp when driving.
Hmm, those weather-reports you linked to on Værnes are way of. In 2010 which was a colder than avg, avg temp in January was 16F. https://seklima.met.no/observations/ Your site reports avg temps higher than what we have here. Don't know where they get their data, but they might be right where you live.
How you use your EV helps determine how useful heat pump would be. I frequently drive 455 miles (732 km) to my hometown, with a longest non-SC stretch of 174 miles (280 km). If I borrow a friend's S85 (15% degradation), I can drive 65mph+ (105kmh) the whole way in summer; but at 14F/-10C with snow, it requires a 1-hour L2 charge on that long stretch. If I could reduce heating energy by 3kw, then I could make that drive without stopping. So for that particular drive, in winter, having heat pump would be as useful to me as the range difference between SR and SR+.
Of course, just buying a bigger battery would compensate for no heat pump; plus, you'd also get to drive further in summer (bonus!). But I think there is a potential customer satisfaction problem with having a car which requires an extra 1-hour stop only in winter. When someone invites you over, it's a bit weird to tell them that you'll come only in summer. Seasoned EV drivers will use a trip planner, and will think about headwinds, road surface and temperature. But until everyone drives an EV and thinks of these things, having such a different range summer vs. winter will make it harder to convince ICE drivers to switch to an EV (at least, where I live).
Of course, just buying a bigger battery would compensate for no heat pump; plus, you'd also get to drive further in summer (bonus!). But I think there is a potential customer satisfaction problem with having a car which requires an extra 1-hour stop only in winter. When someone invites you over, it's a bit weird to tell them that you'll come only in summer. Seasoned EV drivers will use a trip planner, and will think about headwinds, road surface and temperature. But until everyone drives an EV and thinks of these things, having such a different range summer vs. winter will make it harder to convince ICE drivers to switch to an EV (at least, where I live).
I think the lowest hanging fruit would be some better insulation for the battery pack and cabin. This would help cruising efficiency in the winter where today the battery is losing heat and efficiency due to cold airflow under the car.
wdolson
Well-Known Member
As far as cabin insulation goes, the windows are the biggest factor and there isn't much that can be done to insulate them better. They probably do lose some heat out the bottom of the pack in the winter, but it would make things worse the rest of the year. Having a cold soaked battery is a downside when starting out in the winter, but under most conditions the battery warms up to a good temperature after driving a while.
In warmer weather with insulation the battery would require more cooling to dissipate the heat generated from using the battery cells.
That's good to hear. Maybe the next Model S with have heat pump and propane boiler backup!
More seriously, I like the idea of using the motor stators to generate induction heat - albeit 1:1 - when motors not making car move, and if they are already in the heat loop with cabin heating, then that's a good way of using surplus motor heat once batteries are up to temp while the car is being driven and the motors doing useful work.
Personally, I am happy with domestic and EV air to air heat pump, but in my Renault Zoe I did lose all heat when a bad joint vented the gas. And yes, my home system spends too long defrosting in cold, humid conditions, but there is undoubtedly a net benefit.
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I actually have..right now.. bad AC pressure sensor on my Leaf and AC/heatpump is not activating.
I will replace sensor next week.
I've used vehicle for few weeks without Heatpump - all heat is generated with regular PTC heater.
Range drop is noticeable in cold weather. 10% less that normal. But it is above freezing this February.
I will replace sensor next week.
I've used vehicle for few weeks without Heatpump - all heat is generated with regular PTC heater.
Range drop is noticeable in cold weather. 10% less that normal. But it is above freezing this February.
What year Leaf is that? When my dad's 2015 Renault Zoe lost gas pressure, he lost all cabin heat and the compressor became extra noisy. Same with my 2017 Zoe. Renault say 3 year regas is to be expected, but I think these issues are not so different from 'A/C only' system. Although, the more you use it, the more likely some component is to fail eventually.
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ReGas? You mean refill? Actually, if everything is perfect as it should be, no gas will ever leak the system.
Has anybody in the world ever refilled their fridge? No..
Same should be with vehicles. My old BMW has not been refilled with refrigerant for 19 years.
But actually, my dealer added some to Leaf. I'm afraid it might be scam, can't be sure.
They said it lost 75% of the gas. But AFAIK, system will never ever work if so much is lost. So who knows now
did they actually refill or just scammed me.
2014 Leaf.
What I can say that for HVAC to make some heat user HAS to switch on HEAT+AC mode (dehumidified heat)
So if only heating is activated, heat will not be generated as HVAC it tries to heat with HP only.
If HEAT+AC is activated, it tries to use compressor (that doesn't work) to dehumidify and PTC to heat up.
It is possible that refrigerant is low and system tries hard to make some work but is unable. If software is well
made it will not try to do that with low pressure and switch the system off.
Has anybody in the world ever refilled their fridge? No..
Same should be with vehicles. My old BMW has not been refilled with refrigerant for 19 years.
But actually, my dealer added some to Leaf. I'm afraid it might be scam, can't be sure.
They said it lost 75% of the gas. But AFAIK, system will never ever work if so much is lost. So who knows now
did they actually refill or just scammed me.
2014 Leaf.
What I can say that for HVAC to make some heat user HAS to switch on HEAT+AC mode (dehumidified heat)
So if only heating is activated, heat will not be generated as HVAC it tries to heat with HP only.
If HEAT+AC is activated, it tries to use compressor (that doesn't work) to dehumidify and PTC to heat up.
It is possible that refrigerant is low and system tries hard to make some work but is unable. If software is well
made it will not try to do that with low pressure and switch the system off.
Yes - re pressurize. No, it should never happen. I have had many A/C systems (in cars) that stop working so well over the years, and having them 'pumped up' fixes it.
Yes, similar for my dad's car. No way should it lose enough gas in 3 years to completely stop heater and a/c from working. My Zoe did have a bad pipe join (under the battery I was told) so quite a big hassle to fix, but at least they did it under wty. Apparently a re-pressurization every 4 years is a service item I was told. But you never know if they are making it all up!!
Seems scam, especially after "inventing " 1234yf gas that practically doesn't have ANY positive sides.
Upgrading all cars in the world from 134a to 1234yf has... welll. no effect.
Being less than 5000 tons of refridgerant on the world per year. That is a drop in the ocean.
Especially considering 134a is pretty ozone-friendly compared to old chemicals.
Upgrading all cars in the world from 134a to 1234yf has... welll. no effect.
Being less than 5000 tons of refridgerant on the world per year. That is a drop in the ocean.
Especially considering 134a is pretty ozone-friendly compared to old chemicals.
Somewhat counter-intuitive, as you would thing that turning on AC would not help with heating!
But in a fridge / freezer, the compressor motor is sealed inside the system. In a car, the compressor has a mechanical drive from outside, so there are seals that could leak.
Yea that is true for belt-driven compressor. Though it is still meaningless as I just stated, that my 19yo ICE vehicle has never been refilled.
For me, it is absolutely acceptable if vehicle runs out of refrigerant after 20 years.
Could = defect
But EV-s have electric compressors - fully submerged in oil, no rotating shafts to seal.
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