Enduro Battery Heating

[Tr4ckD4ys]

Should I be worried that this winter my battery will be several times in the 30F-40F range when starting to drive?

"Hard floor" as an industry standard is freezing (32F), with 40 being the lowest recommended temp for charge/discharge activity. 90 degrees-ish is the sweet spot for most chemistries for best performance.

The R1's BMS seems content with the battery 50F><120F-ish. When I start out with the batt temp lower than that, it seems to work to move it to over 50 degrees within a few miles. This is very safely within industry standards (which is what one would expect of course).

Should I be worried that this winter my battery will be several times in the 30F-40F range when starting to drive? I keep it around 50%-70% charge at all times.

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[godfodder0901]

QM or DM?

Quad.

 

[R.I.P.]

Should I be worried that this winter my battery will be several times in the 30F-40F range when starting to drive?

Should I be worried that this winter my battery will be several times in the 30F-40F range when starting to drive? I keep it around 50%-70% charge at all times.

No. From what I have seen, Rivian is keeping the pack well within accepted industry standard temperatures. It certainly is not a bad idea to precondition for 20 minutes prior to leaving, just to give your pack a little bit of a head start at warming up. It may or may not make much of a difference, but I see it as just being as nice as possible to the machine.
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[Tr4ckD4ys]

No. From what I have seen, Rivian is keeping the pack well within accepted industry standard temperatures. It certainly is not a bad idea to precondition for 20 minutes prior to leaving, just to give your pack a little bit of a head start at warming up. It may or may not make much of a difference, but I see it as just being as nice as possible to the machine.
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I thought pre-conditioning doesn’t exist? I street park in the city currently, until I have a garage come February.

 

[R.I.P.]

I thought pre-conditioning doesn’t exist? I street park in the city currently, until I have a garage come February.

It will not precondition automatically, but you can manually hit the climate control button in your app and precondition the vehicle.

 

[R.I.P.]

I thought pre-conditioning doesn’t exist? I street park in the city currently, until I have a garage come February.

It will not precondition automatically, but you can manually hit the climate control button in your app and precondition the vehicle.

 

[BCondrey]

I just got 42.2 yesterday for my DM R1T, so I have been for one trip (20 miles mostly highway) with the gauges view, last night.

Battery was cold at 32 degrees when I got in the truck. Battery never got above 42 degrees. Front motor got to 100 degrees, rear motor got to 72 degrees. Outdoor temperatures were about 30 degrees. The battery and motor temps climbed to those levels and stayed there, they were not still climbing after 20 miles. The 20 mile trip home was about the same.

My next outing I will pick a navigation to a local DCFC and see if the behavior changes.

 

[teartags]

I put this in a different post, but will repeat here as it pertains better.
Regular Dual Motor - I've been timing my charging at night so it should be finishing up right after we leave in the morning. Meaning I stop the charge slightly premature. Been chilly here in CO in the morning ranging from 12-20 deg when we load up.
After 6-7 hours charging battery is around 72 deg. Motors are 40-50.
(1 morning after only 2.5 hours charging, battery was 55ish.)
Efficiency is 1.5ish for the 1st 10-15 miles of my commute despite the battery being in the 70's.
When the front motor hits around 95 deg, the efficiency starts to climb back up to 2.3-5. However, there's also a downhill-ish portion of my drive about that time. Though when it levels off and climbs slightly again 3 minutes later the efficiency is still there.
One other note is that I have NO regen limitations at all on the ride. Whereas if it's not warmed up, I definitely do.

 

[Supratachophobia]

I put this in a different post, but will repeat here as it pertains better.
Regular Dual Motor - I've been timing my charging at night so it should be finishing up right after we leave in the morning. Meaning I stop the charge slightly premature. Been chilly here in CO in the morning ranging from 12-20 deg when we load up.
After 6-7 hours charging battery is around 72 deg. Motors are 40-50.
(1 morning after only 2.5 hours charging, battery was 55ish.)
Efficiency is 1.5ish for the 1st 10-15 miles of my commute despite the battery being in the 70's.
When the front motor hits around 95 deg, the efficiency starts to climb back up to 2.3-5. However, there's also a downhill-ish portion of my drive about that time. Though when it levels off and climbs slightly again 3 minutes later the efficiency is still there.
One other note is that I have NO regen limitations at all on the ride. Whereas if it's not warmed up, I definitely do.

I am wondering if the measurement is slightly off because it's calculating some portion of the preconditioning electricity in the mileage calculation even though the trip hasn't started yet. For example, on my Tesla if you run the air conditioner prior to departure for 10 to 15 minute, the efficiency for car is something ridiculous like 1,000 watts per mile until you drive a couple miles and it evens out.

 

[BCondrey]

Some anecdotal data for my Dual Performance Enduro
Started driving today morning:
Outside Temp - 32F
Battery Temp - 36F
Motor Temps - 40F

On the ten mile drive, at arrival time, the data was:
Outside Temp 36F
Battery Temp 49F
Front Motor Temp Hovering between 128F - 135F, never above
Rear Motor Temp Hovering between 95F and 108F, never above

Thats very similar to what I see.

 

[BCondrey]

I've read through this entire post, and it is fascinating. One thing I want to point out is that during the tear down and detailed description the Rivian engineers did on Youtube, they made a big point about how much more efficient the oil-based cooling of the enduro motor is. The oil circulates in the motor cavity, where in the Bosch motor (QM) the glycol cools the outside of the chamber. Seems to make sense, since the QM temps are so much higher than the DM temps.

 

[R.I.P.]

I've read through this entire post, and it is fascinating. One thing I want to point out is that during the tear down and detailed description the Rivian engineers did on Youtube, they made a big point about how much more efficient the oil-based cooling of the enduro motor is. The oil circulates in the motor cavity, where in the Bosch motor (QM) the glycol cools the outside of the chamber. Seems to make sense, since the QM temps are so much higher than the DM temps.

I think you are dead on here.

To get heat "out" from the core of a Bosch requires a lot more energy/heat in the center, because it has to travel all the way to the jacket to get picked up and used. In the Enduro motor, it is picked up where it is created (in the core), meaning the motor does not have to superheat to get similar benefit.

Another nice evolution, and another data point for anybody on the fence about which motor to buy.

 

[teartags]

Can anyone explain why the efficiency is so low even though the battery is "primed"? Is it the motors temp that matters? Or something else that the motors are heating up?
All this talk about including heat pumps on the battery in next gens/ models, but I'm thinking that would have no effect based on what I'm seeing.

 

[R.I.P.]

Can anyone explain why the efficiency is so low even though the battery is "primed"? Is it the motors temp that matters? Or something else that the motors are heating up?
All this talk about including heat pumps on the battery in next gens/ models, but I'm thinking that would have no effect based on what I'm seeing.

A well designed heat pump is a way to "harvest" available heat up to 5x mor efficiently than a resistive heater is able to produce the same number of therms. So yes, a heat pump can indeed save energy in most any system from your home heating to your vehicle. To what extent, is dependent on a great many variables.

As for the low efficiency you ask about, again, a number of factors play in. The motors and the battery are less efficient until they get to their optimal running temperatures. Even "primed" as you put it, a battery that is colder than 70F is going to be less efficient. A motor under 90F has more resistance to it. It all adds up; even in ICE vehicles.

We are just going to use more energy when it is cold. In our homes, in our vehicles. But yea... heat pumps can help.

 

[teartags]

A well designed heat pump is a way to "harvest" available heat up to 5x mor efficiently than a resistive heater is able to produce the same number of therms. So yes, a heat pump can indeed save energy in most any system from your home heating to your vehicle. To what extent, is dependent on a great many variables.

As for the low efficiency you ask about, again, a number of factors play in. The motors and the battery are less efficient until they get to their optimal running temperatures. Even "primed" as you put it, a battery that is colder than 70F is going to be less efficient. A motor under 90F has more resistance to it. It all adds up; even in ICE vehicles.

We are just going to use more energy when it is cold. In our homes, in our vehicles. But yea... heat pumps can help.

Makes sense, and kind of what I assumed. I guess I'm thinking that when Rivian gets around to letting us pre-heat the battery off of the wall power as opposed to the battery, it sholdn't make much difference other than speed.
On the trip I mention above, the battery temp really only changes 1-2 degrees from the 72 it starts from over my 20 min commute (I should add that my commute involves little to no sitting in traffic. 95% driving at 50-70 MPH). However, the efficiency goes up quite a bit at a certain point.
I'll probably never know, but I have fun experimenting.

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