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What's going on (or not going on) with battery conditioning?

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Last week I needed to run a few errands. The car was not plugged in / didn’t need charging-was probably around 35%) and since I didn’t know until the last minute, there was no time for scheduled preconditioning. Ambient was around 50 degrees. I got the limited regen dots due to cold batteries (expected but really annoying to not have the full regen braking you’re expecting). What I didn’t expect is that I drove round trip about 20 miles, and the whole time regen was limited. The rest of the day whenever I needed to go somewhere I’d quickly set up the schedule to precondition (about 10 minutes before departing), but I still got restricted regen. It wasn’t until late in the afternoon after probably three quick trips that it finally didn't have restricted regen anymore (sometimes it would go to full regen, but then would go back to restricted). Ambient was low 50s the whole day.

Today my wife drove the car several times (probably an hour or two after the time I had arbitrarily set for preconditioning and cabin heating). Then around 2:30pm I hopped in to go mountain bike riding, and I got the limited regen dots. I drove (with climate on 72 degrees) for a good 10 minutes and I still had the dots. About 10 minutes before I got back to the car, I stopped and got on my phone and turned climate on (I heard that when you turn climate on, once the cabin is up to temperature, it continues to condition the batteries). When I got back to the car, I still had the limited regen dots.

I then told the car to navigate to the nearest supercharger since I knew it would condition the batteries. About two minutes before I got near the supercharger, the dots went away (I could hear the heat pump working hard to condition the batteries while I was driving). Since I had about 60% in my battery, I cancelled navigation and continued home. In the 4 miles and 8 minutes it took to get home, I got the limited regen dots again (ambient outside was around 53 degrees F.)

I had heard that people might have their car in a relatively warm garage but when they start driving in cold weather, the batteries cool down and it goes into restricted regen. What I was surprised about when I drove is that it didn’t seem to ‘correct’ the temp in flight. I would expect if the batteries are too cold or too hot, it would bring the batteries back to optimum temperature when driving and then you’d get full regen back (and in a relatively short time). And on top of that, it’s not COLD here. Granted, we’re in the upper 30s in the morning right now, but it doesn’t get below 50 in our garage and all the driving has been late morning to mid afternoon when it's in the mid 50s.

Questions:
* How long does preconditioning take (especially for those in colder weather)? If I set my departure time, how long beforehand will it normally start conditioning the batteries?
* Is there any way to precondition the battery without also warming/cooling the cabin (is there another way to turn on preconditioning other than using schedule) or navigating to a supercharger?
* If I'm still getting limited regen dots, what do I do while driving to get the batteries to optimum temperature?
* Is there a way to turn on fast charging pre-conditioning manually if you need to charge at a non-supercharger DC charger (Chargepoint, etc.)? I use onboard navigation on trips so it will precondition before I get to a supercharger, but there should be a way to precondition for fast charging when you’re not using a Tesla supercharger. Supercharger conditioning is much faster (noiser) than scheduled departure conditioning?
* Is preconditioning for driving and preconditioning for supercharger/fast charging the same (in other words, is the optimal temperature the same for driving and supercharging)?
* What is the optimum battery temp for driving? I’ve heard a range between 70 and 90f. 70 makes sense, 90 seems high, especially in the winter.

I'm thinking something is wrong; I can't believe the car wouldn't warm the batteries while driving (even if they hadn't been pre-conditioned). It seems like my batteries just return to ambient even when I'm driving, and then I lose capacity and get limited regen.

Is this going to end up being a service call, or is there something I'm missing?

Thanks in advance.
 
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It just takes time and hard driving to warm the batteries. I've been 25 minutes into a 30 minute highway drive and still had the blue snowflake. Two minutes of more speed and it went away, just in time for me to get off the highway and enjoy that sweet, sweet regeneration!
 
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Its not even that cold where I live in southern california, and I can have regen dots (but no snowflake) for my entire commute to work, which is 39-40 miles one way.

Trying to pre condition to get rid of the limited regen seems like an enormous waste of energy to me, especially now that someone can use the blended brake option if they want it to feel similar to full regen.
 
Bottom line up front: Preconditioning is now accomplished faster, using less energy than was previously the case. Some battery warming is performed, not nearly as much as before. You can drive without concern that regenerative braking may be reduced due to low battery temperature or a high state of charge (or both) if you turn on the blended friction braking function. (Note: If you live at the top of a mountain and start out by descending 1000 feet or more you won't be happy with the new preconditioning protocol, having to choose between limited regenerative braking and the Tesla Model Y automatically continuously applying the friction brakes. For other use cases the blended friction braking is a great option.)

In 2021 Tesla revised the battery warming while preconditioning to use less energy. If you rely on preconditioning to increase the level of regenerative braking (compared with no preconditioning) you will likely have some regenerative braking available but not nearly as much as when the battery is fully warmed; fully warming the battery requires warming the battery to ~21C/70F, takes too long, else requires a much a longer drive, and uses much energy while preconditioning. At 50F preconditioning the Tesla Model Y takes perhaps 5 - 6 minutes before the desired cabin temperature is reached, perhaps 10 minutes as the temperature drops closer to 0C/32F. If the battery is being warmed, you will see the red icon of 3 vertical heating grid elements displayed next to the battery within the Tesla app next to the battery status indicating battery warming is taking place.

With the newer releases of the Tesla software you now have the option to turn on a setting under Pedals & Driving to use the friction brakes in a blended fashion when regenerative braking is otherwise reduced or unavailable. The driving experience with the blended braking is excellent as there is almost no sensation that the friction brakes are doing some/most of the work to slow the vehicle when you lift your foot from the accelerator pedal; it just works. You can observe the blended braking by viewing the power bar while lifting your foot. The green section of the power bar indicates the available regenerative braking while to the left of the green section a dark grey section indicates that blended friction braking is active.
 
I would add that 2021 and up cars with heat pumps and octovalve scavenge heat from the battery to warm the cabin. Even if you were to heat the battery, the car might use that for the cabin which would bring the battery temperature down anyway. The car's software will do what it thinks is best.

Don't worry about it. Don't warm the battery to save energy as others have said. If consistent braking is what you want, do as @jcanoe said and activate friction brake blending instead.
 
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Thanks everyone. I'm anal (and cheap), I refuse to use blended braking and have any of my inertia turned into friction heat. I'll just have to anticipate the lower regen rates and slow down sooner until I get full regen. If I have to use friction brakes, I want to apply them myself so I know when they're being used.

Or, I can just drive more aggressively to warm the batteries faster. No chill mode for me!! 😉
 
Thanks everyone. I'm anal (and cheap), I refuse to use blended braking and have any of my inertia turned into friction heat. I'll just have to anticipate the lower regen rates and slow down sooner until I get full regen. If I have to use friction brakes, I want to apply them myself so I know when they're being used.

Or, I can just drive more aggressively to warm the batteries faster. No chill mode for me!! 😉
I'm confused by this. Weren't you asking about preconditioning? That's kind of a waste. Also, if your Regen is limited... How are you stopping without hitting the brakes? Seems like the blended brake suggestion is a good one since you have no choice but to use the brakes anyway.
 
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This will be my 3rd winter in my LRMY. I am familiar with loss of regenerative braking in colder temperatures. When the power bar displays up to 5 dots indicating that amount of regen is unavailable it is no big deal. When the number of dots reach 9 or 10 dots you effectively have no regen, essentially the Tesla Model Y coasts when you lift your foot from the accelerator pedal. I have preconditioned my Model Y for upwards of 45 minutes in cold weather and still experienced reduced regenerative braking. Now I can precondition for ~10 minutes and drive my Model Y knowing the Model Y will reduce speed exactly as I have come to expect when I lift my foot from the accelerator pedal.

Regenerative braking is great but not losing the experience of one pedal driving when it is cold is also great. That is why I consider the option to enable blended (friction) braking one of the greatest software based enhancements to the Tesla driving experience released to date.
 
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"dots"?

I thought those had been replaced with the new green circular icon

Don't say I have to RTFM again :(
I believe the new green circle icon only applies if you have blended braking enabled. (It flashes on the screen so quickly I have not been able to confirm it.) I can confirm that I see no dots on the power bar with blended braking enabled. I do see a dark grey section to the left of the green section indicating regenerative braking is happening. The dark grey bar is that portion of the braking that is being handled by the friction brakes (could be 30% or more of the total depending on the battery temperature and state of charge.)
 
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If I can revive this thread with a (related) question of my own:

At my local ski hill, there are no charging options (for me). I drive 1.5 hours to a SC, charge up near full, then drive another 1.5 hours to the hill, where there is a big elevation gain. I 'just' have enough battery capacity to make it back to the SC, and then home. I always set pre-conditioning prior to leaving the hill so that I can recapture some of the elevation loss back into the battery (~10%). If I bring up the energy graph before leaving the hill, it shows a substantial increase in charge as I descend.

The last few times, however, I've had no, or almost no regen available, and the brakes are blended in. It sucks seeing the massive grey bar and all the 'lost' energy going to the friction brakes. When I get to the bottom of the mountain, the arrival SoC% is ~10% lower than predicted at the top.

Judging by the comments above, there is no way for me to tell the car to pre-heat the battery more? Seems unlikely that pre-heating would take more energy than a >2k ft elevation change (with the ambient around 0C at the top of the mountain).

Sure would like to make it home without having to stop at the SC.
 
Picking a SC destination doesn't kick the battery heater in until you're driving (or at least in D). I don't really want to sit there with my family in the car waiting while it preheats. I'm 'preconditioned' and would like to hop in and drive home. Last thing I need is kids asking "can we leave yet".
 
I'm on the, allow multiple types of preconditions train. I drive for uber a couple hours in the morning and I have my car set to precondition for 6am departure. It used to be that, with battery set to 80 and preconditions on, I would get in and immediately get most if not all of my regen. But since holiday update or something, my regen pretty much never comes all the way back and it's pretty far gone when i first get in the car.

I'm down with wasting more electricity to get battery preconditions and my regen up because it'll mean my brake pads last longer and I'll have more usable range.
 
> I'll have more usable range

Right. The energy app says I it'll take X% to get home (almost the whole battery) and shows I get +Y% from heading down the mountain. The reality is I burn up my brakes and get 0%. There is no way for the car to know there is a big elevation drop at the start of my drive, so it would be nice to have a manual override option.