The preconditioning myth

[Phatman113]

I precondition all the time in below freezing temperatures, and have the "pull from AC" or whatever checked. It has never, not once, warmed the battery. Battery is always within several degrees of ambient temperature. Gen 1 DM Large.

Schedule precondition? or just clicking the climate button?

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[BCondrey]

^^^^ THIS ^^^^

There is no myth, set a leave time with or without the truck plugged in and it will warm both the cabin and the battery by that time....And the motors as that's what warms the battery.

Doesn't work like that for me. Maybe my truck is broken (Gen1) but the battery never ever warms a bit.

 

[BCondrey]

Schedule precondition? or just clicking the climate button?

Either. I precondition via schedule a couple times a week. Never effects the battery. I preconditioned while plugged in the other day for 30 minutes, and the battery was still cold soaked, close to ambient temp.

 

[André]

I precondition all the time in below freezing temperatures, and have the "pull from AC" or whatever checked. It has never, not once, warmed the battery. Battery is always within several degrees of ambient temperature. Gen 1 DM Large.

That’s probably because your SoC stays over or at the range set while heating the cabin so no charging is required. The battery will be warm-up to 50F only under charging. Try to schedule a charge early before you need your truck and keep SoC below your range set before plugging it. Alternatively you can increase your range set when you manually defrost the cabin to force charging.

 

[Phatman113]

Either. I precondition via schedule a couple times a week. Never effects the battery. I preconditioned while plugged in the other day for 30 minutes, and the battery was still cold soaked, close to ambient temp.

The info I was given directly from Rivian is that it will heat the battery most when the "Pull from charger to maintain range" is selected.. They also didn't comment if regular preheat would heat the battery.

I have confirmed that this works (picture posted earlier) in cold (28*) temps to heat the battery to ~50*, but can't confirm if it's effective when any colder.

 

[BCondrey]

That’s probably because your SoC stays over or at the range set while heating the cabin so no charging is required. The battery will be warm-up to 50F only under charging. Try to schedule a charge early before you need your truck and keep SoC below your range set before plugging it. Alternatively you can increase your range set when you manually defrost the cabin to force charging.

I know that the battery gets warm when it is charging. My SOC is always at target in the morning because I charge overnight. If it only heats the battery while charging, thats useless to me when I want the battery warm before I leave. But, maybe thats just how it is. For some reason I thought conditioning the cabin was supposed to warm the battery if the battery needed it.

 

[Phatman113]

I know that the battery gets warm when it is charging. My SOC is always at target in the morning because I charge overnight. If it only heats the battery while charging, thats useless to me when I want the battery warm before I leave. But, maybe thats just how it is. For some reason I thought conditioning the cabin was supposed to warm the battery if the battery needed it.

https://www.rivianforums.com/forum/threads/the-preconditioning-myth.39300/post-710434

^ it uses the motors to heat the battery when you use scheduled pre-condition and have enabled the option to pull power from the EVSE.

 

[BCondrey]

https://www.rivianforums.com/forum/threads/the-preconditioning-myth.39300/post-710434

^ it uses the motors to heat the battery when you use scheduled pre-condition and have enabled the option to pull power from the EVSE.

I will test this tonight and report back.

 

[DeafPug]

I'm realizing that really poor efficiency is just the nature of this vehicle when its this cold. My drive into work is under 10 miles, and between 6 miles of highway and the rest, I get maybe 1.3 miles per kw. My speeds are around 70mph max. I would set the schedule for my commutes and other days I'd go in on a different day without the schedule. No real difference in efficiency.

just remember that 1.3 mi/kWh is still something like 43.7 MPGe. Even when the R1T is getting terrible efficiency, it’s still better than any gas pickup, even in the best of conditions for the gas vehicle..

 

[stormbreaker]

Thank you @DeafPug for that info. Wasn't aware.

 

[André]

I know that the battery gets warm when it is charging. My SOC is always at target in the morning because I charge overnight. If it only heats the battery while charging, thats useless to me when I want the battery warm before I leave. But, maybe thats just how it is. For some reason I thought conditioning the cabin was supposed to warm the battery if the battery needed it.

That’s why I was telling you to leave it below target so it start charging on a schedule which would allow you to have a warm battery before you leave…

 

[ThirteenElectrics]

Technically preconditioning does not pull shore power from the plug. It pulls from the battery, and then sometime later charges the battery from the plug. So, you can be out 1-2% of charge if you leave before it decides to top off. At least, that has been my experience.

Maybe with the G2s Rivian can pull power directly from the plug like almost every other EV.

 

[hobbyjogger71]

All of this has been a huge example of people inventing what they want to hear and then getting upset when it doesn't the work the way they invented in their head. I haven't done any scientific tests, but in having the truck for 8 months here's what I gather.

1) Charging warms the battery up. At least in G1s. Don't ask the G2 folks how that's going when they need to get to 100%. See the pages long thread about that issue.

2) "Pull power to maintain range" doesn't do anything with shore power - all that does is let the battery power the precondition, and then recharge after it drops 1-2%. If folks are seeing warm batteries using this setting - it's because it decided to top off before you got in.

I'm willing to be wrong about point 2 if someone has definitive proof of the motors spinning while plugged in. I haven't seen an example of that yet - but maybe I'm just as unscientific as the rest of us. What I don't have is a bias towards an outcome I personally want to be true.

This sums up what a few folks upthread have said, but tend to be ignored because it doesn't validate. All in, I find this debate tedius - it only matters if you truly need 100% of the range before a trip. Otherwise, power is power - you're going to be burning kw either way.

 

[Phatman113]

All of this has been a huge example of people inventing what they want to hear and then getting upset when it doesn't the work the way they invented in their head. I haven't done any scientific tests, but in having the truck for 8 months here's what I gather.

1) Charging warms the battery up. At least in G1s. Don't ask the G2 folks how that's going when they need to get to 100%. See the pages long thread about that issue.

2) "Pull power to maintain range" doesn't do anything with shore power - all that does is let the battery power the precondition, and then recharge after it drops 1-2%. If folks are seeing warm batteries using this setting - it's because it decided to top off before you got in.

I'm willing to be wrong about point 2 if someone has definitive proof of the motors spinning while plugged in. I haven't seen an example of that yet - but maybe I'm just as unscientific as the rest of us. What I don't have is a bias towards an outcome I personally want to be true.

This sums up what a few folks upthread have said, but tend to be ignored because it doesn't validate. All in, I find this debate tedius - it only matters if you truly need 100% of the range before a trip. Otherwise, power is power - you're going to be burning kw either way.

#2 is wrong. On Gen 1 at least.
https://www.rivianforums.com/forum/threads/the-preconditioning-myth.39300/post-710698

 

[hobbyjogger71]

#2 is wrong. On Gen 1 at least.
https://www.rivianforums.com/forum/threads/the-preconditioning-myth.39300/post-710698

Do you have any proof? I've never seen it on my Gen 1. The charger logs never wake up, unless its topping off the battery.

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