The preconditioning myth

[Phatman113]

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.

That link shows the motors warmed up.

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[hobbyjogger71]

Fair enough. I'll retry with my own testing tonight.

 

[eskudo12791]

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.

I have emporia vue monitors on all circuits, truck pre conditioned this morning while plugged in and set to pull power, emporia shows exactly 0.00 kwh use today.

 

[hobbyjogger71]

This is what I routinely see with my Emporia as well.

 

[1stPlace]

Here's what I know after many personal tests this week. I have a Gen 1 Quad, but I am almost certain this applies to all Rivians:

If you specifically want your battery at 50degF when you leave, you MUST schedule a climate setting with power pulling from the wall. IN ADDITION, you must make sure that at least 30 min prior to leaving, you have the range set to an amount above what the current battery % state is.

Just turning on climate remotely and/or increasing the range set to charge will not work. The increase people generally see in battery temp from just charging is more gradual, probably just energy transfer heat waste. The vehicle only heats the battery with its motors to 50degF in the scenario I described above. Based on another forum thread, the vehicle occasionally heats the battery to stay above 15degF on its own to likely protect the battery and still accept some amount of DC charging. The vehicle will heat to a much higher ~79-85degF when you select a charging station in navigation and likely when the manual pre-condition button arrives in our software updates.

Now, the only scenario I think you need the vehicle to be 50degF is for absolute maximum range. I mean. set the charger to 90% overnight, then set to 100% in the morning. But if performance isn't affected, and you don't like the actual range at 70% when it's cold then just set it to 80% and forget about battery temp. I do think performance might be affected in regen and max power in the 15degF to 30degF battery temp range, and the car might heat with motors initially to ~30degF on start, but I have not tested this myself. Just a hunch.

 

[Moodist]

Rivian just sent a mail around cold weather checklist

 

[Scottm]

So I was going to try to do some testing in this myself tonight. I have been noticing a discrepancy between the battery temperature display and what ABRP live data shows. The R1T displays 66F and ABRP shows 71.6F. The ~5 degree difference was somewhat consistent as it charged.

I thought it was a problem with ABRP so I checked the RIDE menu and that matched ABRP at 71.6 F, normal truck display still shows 66F.

Is this like a max cell temp vs average temp or what? Do others have this large of a difference? I’m going to let it cold soak outside tonight and see how it behaves in the morning.

 

[Bar_Down]

The schedule climate temperature screen has a section for pulling power from the plug so you can precondition. It will also warm the battery too. Will it matter for range if you don’t need the range?(under 50 mile commute). Probably not but it will be nice and toasty warm when it’s time to leave.

I schedule my charging session to end when I plan to depart on my trips. (This is very helpful when charging to 100% before a long trip). While a pain to do the math, it is straightforward and the happy byproduct is that the battery is warm as well as the cabin with climate scheduling. The battery is generally around 90 degrees in the winter, but I suppose that matters on your charging rate and the length of time it will take to meet.

 

[RexRemus]

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 just watched this happen this past Sunday, motors went over 200+ and battery was heated as soon as I turned on climate in the cabin - I did not engage drive or anything just got in, turned on climate and watched vehicle information screen - motors immediately began heating and the battery temp increased - and my charger did flip to active despite me NOT telling it to charge. I do have "use charger to maintain range" or whatever selected in the charging schedules I have set. But this happened when I manually just turned on climate while it was plugged in.

 

[DuncIT]

If you specifically want your battery at 50degF when you leave, you MUST schedule a climate setting with power pulling from the wall. IN ADDITION, you must make sure that at least 30 min prior to leaving, you have the range set to an amount above what the current battery % state is.

Since initially noticing this thread I've been keeping an eye on things.

I have found that the car pre-conditions regardless of whether it is plugged in or not. I have my R1T set to warm itself up for me every week day morning. On those weekday mornings I see efficiencies of over 3 m/kWh on the way to work. On the weekends, and on weekday evenings (when the car does not warm for me) I see efficiencies of a little over 1.5m/kWh.

I have also noticed that there is very little difference in battery temperature whether it is plugged in or not whilst warming in the morning.

Yesterday evening, no pre-conditioning / warming. Outside temperature was 41 degrees, battery temp was the same.

Yesterday morning, car not plugged in, preconditioned / warmed to 70 degrees. Outside temp 40 degrees, battery the same temp.

Dunc

 

[1stPlace]

I have found that the car pre-conditions regardless of whether it is plugged in or not. I have my R1T set to warm itself up for me every week day morning. On those weekday mornings I see efficiencies of over 3 m/kWh on the way to work. On the weekends, and on weekday evenings (when the car does not warm for me) I see efficiencies of a little over 1.5m/kWh.

I have also noticed that there is very little difference in battery temperature whether it is plugged in or not whilst warming in the morning.

Yesterday evening, no pre-conditioning / warming. Outside temperature was 41 degrees, battery temp was the same.

To clarify first, the word "pre-condition" can apply to car climate, battery, or both. I don't believe you are implying some additional type of "pre-conditioning". Your efficiency during your morning drive is mainly better because the car has already spent energy to bring up the temperature before you stepped in--HVAC is probably the greatest influence you have over your vehicles efficiency WHILE you are driving. Technically, however, pre-conditioning car climate or battery is generally less efficient in terms of OVERALL energy use. The point I think a lot of people keep missing is the efficiency of mi/kWh from the neat little graph on our screens is not overall efficiency. Overall efficiency is the measurement of overall energy use over time.

In the 50k+ miles I've done, I know my R1S has sufficient range. I'm not a hyper miler and I don't worry about the energy cost of setting my home thermostat to 74defF. The energy cost of operating these vehicles is really very low relative to the cost of purchase, so while I find the topic of efficiency interesting, I don't think anyone should truly be concerned, bothered, or change their preferred habits just to achieve greater vehicle energy efficiency.

 

[Singletracker]

I agree with 1stPlace. That 15 minute dash graph is absolutely worthless for determining any sort of actual range efficiency. I don’t even know why it exists.

I also agree that, while we all fixate, myself included, on efficiency numbers as they may relate to maximum potential range, the reality is, in everyday driving, it really doesn’t matter that much. Of course, if one is driving hundreds of miles per day or paying an outrageous amount for electricity, then maybe it’s more of an issue.

FWIW, in my experience, preconditioning the HVB doesn’t seem to have any consistent benefit on efficiency. I have headed out with my battery and motors in the 30ºF or less range and achieved great efficiency #’s. I’ve also headed out after preconditioning/warming my HVB and got crap for efficiency. All this while driving in pretty much the same conditions. There just doesn’t seem to be any rhyme or reason to it. In 16,000+ miles I have yet to discover a consistent pattern ? I have tried! And, darn it, I’m not giving up ?

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