Preconditioning confusion

[Throwdown]

I really think the best option is to have a charging schedule where vehicle will be charged to whatever level you chose by your departure time. This should warm the battery.

This is what I would do if possible, however we have to charge two evs so I run out of time of use time

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[Redline]

Yours warms the battery, mine does not. I'm assuming it only does it if necessary. My garage is insulated so the battery really never gets "cold" unless I don't need to charge for a couple of days

But that’s not what you said lol.

When I’m at home, in my heated garage, it doesn’t need to. At the cabin, where it’s -10, it does.

You claimed it was BS…

 

[Throwdown]

But that’s not what you said lol.

When I’m at home, in my heated garage, it doesn’t need to. At the cabin, where it’s -10, it does.

You claimed it was BS…

I mean I claim it's bs because it's not heating the battery to optimum temp like others have stated it's just heating the battery naturally due to charging. Example I set my preconditioning yesterday and the cabin was fine but the battery was only 58 degrees, not cold but not optimum. Much like vamp drain everyone's results seem to vary

 

[Redline]

I mean I claim it's bs because it's not heating the battery to optimum temp like others have stated it's just heating the battery naturally due to charging. Example I set my preconditioning yesterday and the cabin was fine but the battery was only 58 degrees, not cold but not optimum. Much like vamp drain everyone's results seem to vary

I see what you’re saying.

I’m not 100% sure what optimal battery temp would be, but I’d bet the software is working it into some sort of range.

 

[Throwdown]

I see what you’re saying.

I’m not 100% sure what optimal battery temp would be, but I’d bet the software is working it into some sort of range.

I would assume the middle of the gauge, so around 72F. I'm more familiar with other brands and they say 83F

 

[emoore]

Yours warms the battery, mine does not. I'm assuming it only does it if necessary. My garage is insulated so the battery really never gets "cold" unless I don't need to charge for a couple of days

It will only warm the battery if needed. A 58F battery isn't a cold battery, it's close to nominal. A 15F battery is a cold battery and it will heat it up when scheduled departure is activated. Calling it BS because it doesn't heat yours in an insulated garage is a bit of a stretch.

 

[Singletracker]

I can’t remember the last time my battery saw 72 degrees. It usually settles in at the 50-60 range. And, even that will take a bit of driving. I would have to drive quite awhile to see much over 60 degrees, at least this time of the year. So, I’m not sure what the optimal temperature should be. To say that there is a variation in what people are experiencing would be a true understatement.

 

[Throwdown]

It will only warm the battery if needed. A 58F battery isn't a cold battery, it's close to nominal. A 15F battery is a cold battery and it will heat it up when scheduled departure is activated. Calling it BS because it doesn't heat yours in an insulated garage is a bit of a stretch.

58 likely isn't close to optimal, idk what rivian considers I assume around 70 cuz thats where the line in the gauge is. batteries like to be hot. I call it bs because it is, mine isn't preconditioning the battery any more than what it would normally heat to when charging at this ambient temp

 

[Marchin_MTB]

not to muddy these waters anymore than Rivian already did, but my belief based on rivians past statements was that the vehicle autonomously warms the battery at certain temperature set point, no matter what. This would make it difficult to attribute cause and effect in colder climates since the cabin preconditioning and BMS functionality could be independent of each other.

In my observations of vampire drain there is a very significant jump in power usage as temperatures dip somewhere between 30 and 50 deg F. That occurs without any preconditioning whatsoever and I attribute it to the BMS warming up the battery.

But I realize that I may be conflating the BMS keeping the battery above X vs. “Preconditioning” heating the battery up to an optimal temperature from shore power prior to driving.

I definitely would like Rivian to explain all this functionality better.

 

[emoore]

58 likely isn't close to optimal, idk what rivian considers I assume around 70 cuz thats where the line in the gauge is. batteries like to be hot. I call it bs because it is, mine isn't preconditioning the battery any more than what it would normally heat to when charging at this ambient temp

It’s probably close enough so no need to waste energy heating up a semi warm battery. Try parking outside and cold soaking the battery. Then you will see it preconditioning.

 

[Throwdown]

It’s probably close enough so no need to waste energy heating up a semi warm battery. Try parking outside and cold soaking the battery. Then you will see it preconditioning.

That defeats the purpose of the option of having it pull from the grid. We're all making assumptions on what battery precondtioning is to the rivian. They were nice enough not to tell us what the battery temp for preconditioning would be. Of course it will heat the battery at any time it needs to but nobody knows what that threshold is. I've seen mine heat the battery while driving when the battery showed 42F which seems like a waste of energy to me. We also are all assuming the temp values it shows us are actual, which they probably aren't all the time

 

[Riviot]

BTW, prior to 50.01, on cold mornings, without preheating the battery, my motors would gradually heat up, sometimes into the 270+ range. Now, they barely reach 100 degrees, after miles of driving. So, something major changed with my T. Yesterday, after the truck sat out overnight in freezing weather, I drove 20 miles In 45 degrees weather. The motors barely nudged 100 by the end of the trip. The battery temp stayed in the mid-40’s. The efficiency was WAY better in those conditions than I had ever experienced. Go figure.

Do you have DM or quad?

@R.I.P. you switched from quad to DM, right? Previously I understood that in warm weather DM was more efficient at temp management than quad, something to do with being easier to shed temps with air gap instead of oil. In cold temps trying heat things up, do you think quad would be more efficient than DM at transferring heat to batteries?

 

[emoore]

That defeats the purpose of the option of having it pull from the grid. We're all making assumptions on what battery precondtioning is to the rivian. They were nice enough not to tell us what the battery temp for preconditioning would be. Of course it will heat the battery at any time it needs to but nobody knows what that threshold is. I've seen mine heat the battery while driving when the battery showed 42F which seems like a waste of energy to me. We also are all assuming the temp values it shows us are actual, which they probably aren't all the time

Then it’s not BS. Rivian heats the battery when their engineers determine it needs it. Not sure why that’s so controversial.

 

[R.I.P.]

Do you have DM or quad?

@R.I.P. you switched from quad to DM, right? Previously I understood that in warm weather DM was more efficient at temp management than quad, something to do with being easier to shed temps with air gap instead of oil. In cold temps trying heat things up, do you think quad would be more efficient than DM at transferring heat to batteries?

Yes, I went from QM to DM.

No, the quad has a terrible cooling design, and that will certainly not make it more efficient as a heater. That is why it has to get super hot to pull any usable heat off of it for the batteries.

The heat in the motor is being created at the center, at the armature. The Bosch design tries to take the excess heat off of the case to cool it. This is like running an air conditioner in a back bedroom to cool the living room; with all the doors closed.

For the Enduro, Rivian adopted the Tesla design of bathing the heated components in oil, then cooling the oil via a heat exchanger. This is about as good as it gets. This is why the Enduro not only has much better cooling, but it is able to quickly and efficiently get heat to the batteries when needed as well... at half the temps the Bosch needs to do the same job.

 

[PhatDaddy]

… the quad has a terrible cooling design… that is why it has to get super hot to pull any usable heat off of it for the batteries… the Enduro not only has much better cooling, but it is able to quickly and efficiently get heat to the batteries when needed as well... at half the temps the Bosch needs to do the same job.

Odd… seems like this would make the Enduro motors better designed, less susceptible to heat-induced damage, etc… and so would have given longer (or at least equal) warranty period. Granted, there are lots of other possible reasons Rivian could have opted for the shorter warranty on the Enduro-equipped vehicles… including less long-term trust in their own, less proven design.

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