Having Cold-soaked battery warming issues? Turn off regenerative braking assist

This morning on my way into work, after driving for about 15 minutes I went to check out what my battery temps were. Vehicle was sat outside unplugged since Saturday afternoon. I used the scheduled precondition this morning, cabin was toasty warm at 7:30 but I hadn't thought to check what the battery or motors were at when I left. It was 18F outside.



Pretty obviously the truck wasn't trying to warm up the battery anymore if it had during the schedule (I'll assume it had but this would have been better if I had verified it).

So I had a thought. This behavoir didn't exist before 2023.50.1, what had changed? Rivian added "Regenerative braking assist" that's enabled by default. I turned it off. After perhaps 30 seconds it was obvious my truck had begun warming the motors up to put more heat into the battery. Of course this also meant that I had very little off-pedal braking and had to use the physical brake again.



I checked again after ~10 more minutes of driving and the motors were now quite warm again.


And just prior to getting to work, the heating was in full effect.



I really think Rivian should give us some sort of a notification when they are conditioning the battery for any reason. Perhaps also give us a method of forcing it on until the battery reaches a specific goal (maximize regen/power output/prepare for fast charging) as all of those temperatures seem to be a little different.

I think you just mentioned the best solution - Allowing us to specifically choose to precondition the battery or at least tell us which existing settings include it.

I think the precondition should include warming the battery regardless as long as the truck is plugged in.

And please no more warning dialogs that pop on top of something that I may need to see, quickly disappear, are not recallable, and do not have a corresponding "off" dialog. I am usually in the process of backing out of my driveway, it's dark, using cameras, checking the shared driveway for other traffic, and these things at first made me go "wuh?" and now I just ignore them. Excrutiatingly poor user experience.

Donald Stanfield said:

I think the precondition should include warming the battery regardless as long as the truck is plugged in.

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For sure, but plugging in is not always an option, especially during travel. If I had been in a situation where I needed to use a DC charger that wasn't on my nav this morning after driving 20 miles, it would have been quite irritating having to wait the extra time for the battery to warm up.

Dark-Fx said:

For sure, but plugging in is not always an option, especially during travel. If I had been in a situation where I needed to use a DC charger that wasn't on my nav this morning, it would have been quite irritating having to wait the extra time for the battery to warm up.

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Yeah you're right it should allow you to choose it for that reason.

Donald Stanfield said:

Yeah you're right it should allow you to choose it for that reason.

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At least being able to get things up to 50F, where the vehicle seems to warm the battery to for regen purposes, would be way better than 30F or lower. Which is why I decided to post about this as I hadn't seen this side-effect of the regenerative braking assist option mentioned before.

Dark-Fx said:

At least being able to get things up to 50F, where the vehicle seems to warm the battery to for regen purposes, would be way better than 30F or lower. Which is why I decided to post about this as I hadn't seen this side-effect of the regenerative braking assist option mentioned before.

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I'm not 100% sure it's tied to the new regen braking option. The other day I was explaining the process to my children as we drove. To illustrate the heating effect, I selected the motor temps tab and noticed that the ~35F battery was NOT causing the motors to heat, despite what I had been telling my children for the last 10 min. Fast fwd 5 more min, and the motor temps began to rise dramatically.

Long story short, it takes way longer than I expected for the motors to start to heat up. Oh, and I had previously turned the new assist option off about 30 seconds into my first drive with it.

godfodder0901 said:

Long story short, it takes way longer than I expected for the motors to start to heat up.

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My first photo was after 15 minutes of driving and an entire key-cycle from dropping my kiddo off at school. Immediately after flipping the option over, my truck notified me that braking performance was reduced due to the low battery temperature. I can't think of any logical reason it would intentionally wait 15 minutes but perhaps another round of testing is needed.

Dark-Fx said:

My first photo was after 15 minutes of driving and an entire key-cycle from dropping my kiddo off at school. Immediately after flipping the option over, my truck notified me that braking performance was reduced due to the low battery temperature. I can't think of any logical reason it would intentionally wait 15 minutes but perhaps another round of testing is needed.

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I'm curious if Rivian has captured enough data on average trips to determine that they should delay heating the battery up until 15 minutes or so has happened. I know there have been a lot of posts recently of people complaining about efficiency since it got cold out and delaying the battery heat up would help lessen that if most trips are less than 15 minutes.

I would love the option to heat up the battery during preconditioning while plugged in, though.

Spork8 said:

I'm curious if Rivian has captured enough data on average trips to determine that they should delay heating the battery up until 15 minutes or so has happened. I know there have been a lot of posts recently of people complaining about efficiency since it got cold out and delaying the battery heat up would help lessen that if most trips are less than 15 minutes.

I would love the option to heat up the battery during preconditioning while plugged in, though.

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Oh, another datapoint, the heating seemed to stop after I flipped the brake assist setting back on. I only did that in the final minute of my commute. Didn't use the navigation for my commute so it wouldn't have known I was going to be done driving soon.

I wonder if in the same situation (unplugged overnight in cold weather) selecting a DCFC somewhere near your morning destination in the nav so it starts the preconditioning immediately would make a difference.

Donald Stanfield said:

I think the precondition should include warming the battery regardless as long as the truck is plugged in.

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It does, or at least I'm pretty sure it does.....but that's hard to do when the battery is "cold soaked" and the vehicle is not moving or plugged in. Where would they get the heat from?
When I schedule departure, my cabin and battery were conditioned just fine at 0530....and it's closer to 12 degrees in the mornings here over the past few days....but I'm also drawing power from my home charger to do it.

COdogman said:

I think you just mentioned the best solution - Allowing us to specifically choose to precondition the battery or at least tell us which existing settings include it.

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Nothing to do with regen braking. That option was added simply because when the battery is so cold, regen doesn't work (well at least) because the battery is not able to accept incoming energy until it warms up (same with Tesla and other EVs).
Suggest you set departure time and have Rivian plugged in so it can pull power to warm up. How do you expect the "cold soaked" battery to warm up when it's not drawing power from anywhere but itself and the vehicle isn't moving (so how are the motors going to magically warm up?).
Agree as far as a specific precondition button in case you're heading for a charger that isn't in Rivian's navigation.

**But..if the vehicle was unplugged in teen-temps for two days, you it can't just heat itself up by magic...it needs to draw energy from somewhere (charger or movement)....next time, just leave it plugged in when not being used (especially when its this cold).

Dark-Fx said:

My first photo was after 15 minutes of driving and an entire key-cycle from dropping my kiddo off at school. Immediately after flipping the option over, my truck notified me that braking performance was reduced due to the low battery temperature. I can't think of any logical reason it would intentionally wait 15 minutes but perhaps another round of testing is needed.

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I couldn't either; that's what confused me the most. Perhaps there is an intentional delay to prevent over cycling the motors, or maybe there is some logic (or ICVs) being run to determine if and at what level heat is actually required?