It makes a massive difference; on a recent trip in -25C temps, the first half of the trip (with the Supercharger in the destination and pre-conditoning) useage was well over 300 Wh/km; the second half of the trip to my house with no preconditioning was around 204 Wh/km. Cruise set at 115 km/h for both sections of the trip.
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Superchargers: 150kW, 250kW ... is there much difference?
- Thread starter EVer Hopeful
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No one said that battery preconditioning didn't consume any power. What we're saying is that the new method which heats more gently during a longer period doesn't seem to take more power than the previous method that heat more aggressively during a shorter period. And as a bonus it's now gentler on the motors/electronics as well as the battery.
That has been my real world experience. I don't know if/when it actually happened, but my Supercharger preconditioning experience from Aug'20 to about Nov'20 was that it only preconditioned for about 15 to 20 minutes before arrival. After that it seems to precondition an hour or more before arrival.
I think it actually also has to do with anticipated arrival SoC. If it thinks you're going to arrive very low it won't spend more energy warming up. If you're going to arrive with plenty then it'll use energy to warm itself ahead of time. But I have no Tesla documented evidence of this.
NeverGoingBack
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NeverGoingBack
De-ICEd
I'll test this at some point this winter but from what I'm seeing now, there's no difference in the coolant flow, Stator motor temps, coolant temp prior to entering the battery pack, etc. I have my logs pre-2021.4.11 and post-2021.4.11, so I'll be able to compare with the more recent software updates.
While the vehicle is in motion, the front Stator motor draws typically 2.0 kW for the preconditioning. It'll waver and bounce around between 1.5-2.5 kW but generally, it's around 2.0 kWh. Since dual motor 3 and Y are 100% RWD unless there's a traction issue on the rear axle, or more power is needed, the front motors don't really generate any heat in normal driving conditions, which is why the Stator motors draw energy to produce heat. Since the front motor is induction and the rear is a permanent magnet, induction motors are less efficient (produce more heat), so Tesla designed their system to draw more heat from the front motor. The highest I've seen the front Stator reach is 253F. The highest I've seen the rear Stator motor reach is 205F.
TLDR roughly 2 extra kW to precondition (per hour), assuming the vehicle remains in motion.
Here's a datalog from early winter 2020, prior to the first cold weather update that started the preconditioning process earlier. This is when the community noticed the car would pull heat from the battery pack to warm the cabin, resulting in a colder-than-normal battery pack, preventing fast supercharging (and slower acceleration).
I read that they recently changed the preconditioning strategy to start earlier at a lower power level rather than heating the coolant to a high temperature for a short period of time... there is a lot of speculation as to why they changed the strategy, most think it is less stressful to the battery to warm it over a long period of time rather than heating it up rapidly.
Keith
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