Optimal Battery Temperature for best performance?

[zefram47]

14 mile somewhat downhill commute and I went from 78F to 80F on the battery temps. Similarly, was surprised at how front-biased the motors are on acceleration and how little regen they attempt to pull from the rear motors. Motor temps seemed to like hovering around 109F and got up to 140F at one point with a lot of regen coming off the highway. The red line on the motor temp graph was way the hell up there though. I kinda want to go try my rock wall climb again to see what temp the motors get to before I get turtle mode again.

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[kurtlikevonnegut]

Should I be concerned that on a relatively cool day here (about 50 degrees outside) my battery was at 100 degrees right off the bat and stayed around 99 for the entire drive to work? Seems like my battery was running a lot warmer than most of the other people reporting battery temps, especially given the relatively low ambient temperature.

 

[R1Tom]

Should I be concerned that on a relatively cool day here (about 50 degrees outside) my battery was at 100 degrees right off the bat and stayed around 99 for the entire drive to work? Seems like my battery was running a lot warmer than most of the other people reporting battery temps, especially given the relatively low ambient temperature.

I wonder if yours was cold enough ambient, that it went into a heat mode to warm battery and when it makes that transition, it then goes to a 100 degF setpoint?

I have noticed in past...my range hits are very discrete with ambient temps. Like it's almost an all or nothing decision being made by battery management at some ambient temp in the 50 deg range I recall.

 

[ksujeff99]

Should I be concerned that on a relatively cool day here (about 50 degrees outside) my battery was at 100 degrees right off the bat and stayed around 99 for the entire drive to work? Seems like my battery was running a lot warmer than most of the other people reporting battery temps, especially given the relatively low ambient temperature.

This will be interesting to watch - what’s the day to day like, how warm the battery gets during preconditioning, does charging at 48a v. something less puts more significantly heat in the battery, how much the battery cools sitting outside overnight. Data is awesome!

Mine was 88º this morning after charging from approximately 40% to 70% overnight.

I also noticed a change (for the better) in my efficiency graph after the update. For the last several months I’ve seen horrible efficiency during the first 5-10 minutes of a trip, regardless of whether the battery was warm, whether I was using A/C or heat, outside temperature, 1st trip or 10th trip of the day, etc. This morning I saw a great improvement. The question that only Rivian would know though is whether this was just a reporting error or whether the truck really was less efficient during these times.

 

[zefram47]

Should I be concerned that on a relatively cool day here (about 50 degrees outside) my battery was at 100 degrees right off the bat and stayed around 99 for the entire drive to work? Seems like my battery was running a lot warmer than most of the other people reporting battery temps, especially given the relatively low ambient temperature.

Can you tell if charging finished near your departure time? Charging the battery will naturally warm it up. I only charge at 24A, so I wouldn't expect mine to get all that warm. Also, more kWh added the warmer I'd expect it to get. But 100F is not "hot", so I wouldn't worry about it at all. If anything, my 78F may have been "cool" since I didn't get full regen right off the bat even though I was only at 75 %SoC.

 

[kurtlikevonnegut]

Can you tell if charging finished near your departure time? Charging the battery will naturally warm it up. I only charge at 24A, so I wouldn't expect mine to get all that warm. Also, more kWh added the warmer I'd expect it to get. But 100F is not "hot", so I wouldn't worry about it at all. If anything, my 78F may have been "cool" since I didn't get full regen right off the bat even though I was only at 75 %SoC.

I charge at 48a from a Rivian charger. Last night I added about 50kwh (30-70% SoC) and it should have ended around 3 hours before I left, although it was plugged in right up until departure so it's possible that it had just "topped off" the battery as I've noticed that it charges to the cut off point and then periodically adds 1-2% as needed when plugged in.

 

[godfodder0901]

If anything, my 78F may have been "cool" since I didn't get full regen right off the bat even though I was only at 75 %SoC.

That's odd. At 77F, I had full regen available.

 

[zefram47]

I charge at 48a from a Rivian charger. Last night I added about 50kwh (30-70% SoC) and it should have ended around 3 hours before I left, although it was plugged in right up until departure so it's possible that it had just "topped off" the battery as I've noticed that it charges to the cut off point and then periodically adds 1-2% as needed when plugged in.

Yeah, I typically only add 10-15 kWh on the daily. The battery is also large, so there's a lot of thermal mass in play. If it's parked in a garage that will tend to moderate the effect of outdoor temps too. Just one more metric that will be fun to watch over time to see how the truck behaves. Too bad that metric isn't available in the API for ElectraFi to track for us.

 

[zefram47]

That's odd. At 77F, I had full regen available.

Note, it didn't show reduced regen on the dash. I just noticed immediately that when fully lifting off the throttle the green bar didn't go all the way to the bottom of the gauge and it didn't feel as strong as I'd expected. Enough that I had to go for the brakes because the anticipated deceleration wasn't achieved. It was back to normal after a couple stops though.

 

[Dark-Fx]

Should I be concerned that on a relatively cool day here (about 50 degrees outside) my battery was at 100 degrees right off the bat and stayed around 99 for the entire drive to work? Seems like my battery was running a lot warmer than most of the other people reporting battery temps, especially given the relatively low ambient temperature.

I would not worry unless it's over 115F or so.

 

[Marchin_MTB]

I wonder if yours was cold enough ambient, that it went into a heat mode to warm battery and when it makes that transition, it then goes to a 100 degF setpoint?

I have noticed in past...my range hits are very discrete with ambient temps. Like it's almost an all or nothing decision being made by battery management at some ambient temp in the 50 deg range I recall.

Interesting observation. I noticed this bi-modal Behavior is also true of vampire drain, probably for the same reason.

 

[WSea]

Should I be concerned that on a relatively cool day here (about 50 degrees outside) my battery was at 100 degrees right off the bat and stayed around 99 for the entire drive to work? Seems like my battery was running a lot warmer than most of the other people reporting battery temps, especially given the relatively low ambient temperature.

Did you charge overnight?

 

[Electrified Outdoors]

Something i have noticed over yesrs of driving EV is that in the winter months performance is less. This will be our first winter with the Rivians but its safe to say that performance will be reduced due to less available power output from battery due to colder temps. Especially once we get into the winter months and it starts getting cold soaked.

On the motors, I was told prior the truck was "front biased". Its the opposite of what Tesla does. Tesla relies primarily on the rear motor. I think its great that Rivian is showing us what is going on in real time.

Neither of mine have received the update as yet. Curious to try it out.

 

[bael]

Short trip (12 miles) and I saw as high as 132F for the front motors. Of note, I was surprised at how front-biased the truck is in All Purpose. Not just regen (which ends at 100% front when stopping), but acceleration as well.

These were my thoughts as well. Was surprised how much of a bias there was for front in AP. Fun having the stats now.

Drove a good bit this morning with cooler temps (50-62 ambient) and battery stayed around 68/69

 

[kylealden]

Don't get me wrong, I love the new dashboard, but I bet some Rivian PM is watching this thread muttering "I told you so" ? It's just the right amount of information to get us all speculating and second guessing and correlating instead of just trusting the truck.

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