Preconditioning confusion

[Riv_Goat]

I thought the "snowflake" and "three red wiggly up-arrow" buttons only impacted whether you wanted to ventilate or heat the seats, not whether you wanted heat vs. A/C in the cabin.

You thought correct.

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[jeffguitardavis]

I am not sure what the confusion is, maybe this will help:

• The R1 will warm, or "condition" the battery using heat off the motors if the BMS deems is necessary for the health of the battery, or, if it will assist in fast charging.
• This "conditioning" can be triggered by the vehicle, such as when it is aware that it will be fast charging.
• The vehicle does not have to be moving for this to happen.
• This "conditioning" can also be triggered by a the user by starting the climate control (whether scheduled or not).
• The latter trigger is simply to get the battery above critical floor levels (which the industry agrees is between 32 and 40 degrees F).
• In tests I have done, the R1 will not not normally trigger external warming (the motors) if over 50 degrees F unless it is in preparation for DCFC.

This is demonstrable, documented and reasonable behavior many of us have watched with the Rivian BMS.

does that help?

This is very helpful R.I.P. Thank you!

Apologies up front. This is a long post.

I want to submit a follow-up question just for clarification regarding "preconditioning best practice" under different scenarios given the summary from R.I.P. above. This is specifically focused on cold weather scenarios with the variable as to whether the vehicle is connected to a L2 "home" charger or not.

It seems to me that there are 3 main use cases:


Heat The Cabin
It's cold outside and the car is parked and the cabin is cold as well. I want to get in the car without it being so cold.

Options:

1. Some time before departure, use the app to schedule the heating of the cabin to a specific temp for a specific time.
2. Some time before departure, go to the car itself and manually set the temp and get the car to start heating the cabin.

Best Practice: probably more convenient to use the app - that's why that feature exists. However, either is an option.


Precondition The Battery For Efficient Driving
It's cold outside and the car is parked and the battery is below "critical floor levels" (<40 degrees F). The scenario assumes you are not going to a DCFC anytime soon. It's simply to get the battery to be more efficient for driving.

Options:

1. As with the "Heat The Cabin" scenario, some time before departure, use the app to schedule the heating of the cabin. This will trigger the BMS to determine if the battery temp is too cold and will commence heating the battery simply to get it above critical floor level temp. The BMS will not heat the battery to a warmer temp to optimize it for DCFC since the vehicle was not "told" that DCFC is imminent.
2. Same as #1 but go to the car and do it manually.

Best Practice: same as "Heat The Cabin".

NOTE: I do not see any option in the app nor in the vehicle to directly tell the vehicle to heat the battery. The only user-based control in either the app or the vehicle that I can see is cabin temp control.

These two above scenarios can be combined into: "Get the car ready to drive so we are comfortable and the car is reasonably efficient."


Precondition The Battery For Efficient DCFC
It's cold outside and the car is parked and the battery is below "critical floor levels" (<40 degrees F). The scenario assumes you actually are going to charge at a DCFC very soon AND you do not have a home charger available.

This is exactly the scenario we experience up in Tahoe when preparing to drive back home (S.F. Bay Area). The battery is quite cold and we need to go to the Truckee RAN to charge before heading back home.

Options:

1. Set the nav to go to the DCFC RAN station so the car knows DCFC is imminent. However, since you are not connected to an L2 charger overnight, this is the "rob Peter to pay Paul" scenario as mentioned by others in various threads. You need to run the motors to get the fluid hot to then circulate to the battery to warm it up but you can't draw from a charger to do that. Thus, the only place is the battery and that just drains the battery.
2. There is no option 2 (or Rule 6 for those Monty Python fans out there).

The result for us is that we get to the RAN in Truckee with a battery that is still WAY too cold for efficient DCFC. Once we connect to a RAN station, then the heating of the battery starts up. This can take quite a bit of time before the battery is even close to warm enough to then charge at a fast rate. We have had mornings where the RAN in Truckee is going at only 20-30kW (not a misprint) for ages.

What we do now is charge up in Truckee when we arrive so we do not have to charge in cold conditions on the way back. We make sure we have enough charge to get to the Sacramento RAN and we charge up there.

Best Practice: what would be the best practice in this case?


Two questions:

1. Is this an accurate summary?
2. Is cold battery preconditioning for efficient DCFC without being connected to a home charger impossible if the DCFC is very close (short driving time to get to the RAN)?

 

[R.I.P.]

This is very helpful R.I.P. Thank you!

Apologies up front. This is a long post.

I want to submit a follow-up question just for clarification regarding "preconditioning best practice" under different scenarios given the summary from R.I.P. above. This is specifically focused on cold weather scenarios with the variable as to whether the vehicle is connected to a L2 "home" charger or not.

It seems to me that there are 3 main use cases:


Heat The Cabin
It's cold outside and the car is parked and the cabin is cold as well. I want to get in the car without it being so cold.

Options:

1. Some time before departure, use the app to schedule the heating of the cabin to a specific temp for a specific time.
2. Some time before departure, go to the car itself and manually set the temp and get the car to start heating the cabin.

Best Practice: probably more convenient to use the app - that's why that feature exists. However, either is an option.


Precondition The Battery For Efficient Driving
It's cold outside and the car is parked and the battery is below "critical floor levels" (<40 degrees F). The scenario assumes you are not going to a DCFC anytime soon. It's simply to get the battery to be more efficient for driving.

Options:

1. As with the "Heat The Cabin" scenario, some time before departure, use the app to schedule the heating of the cabin. This will trigger the BMS to determine if the battery temp is too cold and will commence heating the battery simply to get it above critical floor level temp. The BMS will not heat the battery to a warmer temp to optimize it for DCFC since the vehicle was not "told" that DCFC is imminent.
2. Same as #1 but go to the car and do it manually.

Best Practice: same as "Heat The Cabin".

NOTE: I do not see any option in the app nor in the vehicle to directly tell the vehicle to heat the battery. The only user-based control in either the app or the vehicle that I can see is cabin temp control.

These two above scenarios can be combined into: "Get the car ready to drive so we are comfortable and the car is reasonably efficient."


Precondition The Battery For Efficient DCFC
It's cold outside and the car is parked and the battery is below "critical floor levels" (<40 degrees F). The scenario assumes you actually are going to charge at a DCFC very soon AND you do not have a home charger available.

This is exactly the scenario we experience up in Tahoe when preparing to drive back home (S.F. Bay Area). The battery is quite cold and we need to go to the Truckee RAN to charge before heading back home.

Options:

1. Set the nav to go to the DCFC RAN station so the car knows DCFC is imminent. However, since you are not connected to an L2 charger overnight, this is the "rob Peter to pay Paul" scenario as mentioned by others in various threads. You need to run the motors to get the fluid hot to then circulate to the battery to warm it up but you can't draw from a charger to do that. Thus, the only place is the battery and that just drains the battery.
2. There is no option 2 (or Rule 6 for those Monty Python fans out there).

The result for us is that we get to the RAN in Truckee with a battery that is still WAY too cold for efficient DCFC. Once we connect to a RAN station, then the heating of the battery starts up. This can take quite a bit of time before the battery is even close to warm enough to then charge at a fast rate. We have had mornings where the RAN in Truckee is going at only 20-30kW (not a misprint) for ages.

What we do now is charge up in Truckee when we arrive so we do not have to charge in cold conditions on the way back. We make sure we have enough charge to get to the Sacramento RAN and we charge up there.

Best Practice: what would be the best practice in this case?


Two questions:

1. Is this an accurate summary?
2. Is cold battery preconditioning for efficient DCFC without being connected to a home charger impossible if the DCFC is very close (short driving time to get to the RAN)?

For #1, yes, it is.

For #2: you have three options in this scenario.

1. The obvious, go to the truck, tell it where you are going, and let it start to precondition as you go to DCFC. Obviously, with the DCFC being so close, charging is going to begin very slowly. As you know. Some time wasted, but the vehicle will do what it can until it's warm.

Option two. Precondition using the app about 30 minutes prior. This will get things started in the right direction, and will give the vehicle a little bit of a head start.

Option number 3. Actually go to the vehicle, and punch in your destination 15 minutes prior to leaving. Lock the vehicle back up with either the key left inside or a front seat belt buckled (to keep it running) so it can start DCFC prepping. I find 15 to 20 minutes of this will usually have it pretty close to DCFC temps by the time I get back to the truck.

The times we have done this side by side the DM seems to work a hell of a lot better in this scenario. The DM warms the battery quicker, with motor temps seldom going much over 100°. The QM's warm the battery much slower, with well over double the motor temps observed. This of course is due to the DM's more efficient motor cooling design, which also makes for a much more efficient heat wicking design. That said, you might Budget more preheating time if you are driving a QM.

Unless there is a time crunch factor once I set off (rare), I usually opt for option number two.

 

[jeffguitardavis]

Thanks so much R.I.P. for the quick response.

So sorry for my ignorance but what does DM and QM refer to?

 

[R.I.P.]

Thanks so much R.I.P. for the quick response.

So sorry for my ignorance but what does DM and QM refer to?

Dual motor (Enduro) or quad motor (Bosch).

 

[jeffguitardavis]

Dual motor (Enduro) or quad motor (Bosch).

Jeez. Should have known that considering I used to be at Rivian in Palo Alto. Need more coffee obviously. LOL.

Our R1S is a Bosch Quad Motor configuration. The Enduro motors are slick, though.

Full specs:
Version: R1S Launch Edition
Exterior Color: El Cap Granite
Interior Color: Ocean Coast
Wheels/Tires: 20" AT Brights
Delivery Date: June 20, 2023

 

[R1Tom]

For #1, yes, it is.

For #2: you have three options in this scenario.

1. The obvious, go to the truck, tell it where you are going, and let it start to precondition as you go to DCFC. Obviously, with the DCFC being so close, charging is going to begin very slowly. As you know. Some time wasted, but the vehicle will do what it can until it's warm.

Option two. Precondition using the app about 30 minutes prior. This will get things started in the right direction, and will give the vehicle a little bit of a head start.

Option number 3. Actually go to the vehicle, and punch in your destination 15 minutes prior to leaving. Lock the vehicle back up with either the key left inside or a front seat belt buckled (to keep it running) so it can start DCFC prepping. I find 15 to 20 minutes of this will usually have it pretty close to DCFC temps by the time I get back to the truck.

The times we have done this side by side the DM seems to work a hell of a lot better in this scenario. The DM warms the battery quicker, with motor temps seldom going much over 100°. The QM's warm the battery much slower, with well over double the motor temps observed. This of course is due to the DM's more efficient motor cooling design, which also makes for a much more efficient heat wicking design. That said, you might Budget more preheating time if you are driving a QM.

Unless there is a time crunch factor once I set off (rare), I usually opt for option number two.

I wish they would show us the coolant loop temps. It would be interesting to see how much hotter the loop temps are for the DM than the QM in the scenario of preheating the battery.

 

[POLAR1S]

1. If you do manual starting the climate, it will only warm up the cabin. If you set it thru schedule, it will warm up the cabin and the battery as well. My battery was at 70 degree this morning when I left the house in 15 degree weather.
2. Rivian should develope a push button just for battery condtioning anytime you want instead of thru rivian nav. system. The different is probably a few minutes at most when you are charging with a cold battery and preconditioned battery.

2. Have you heard of Human Battery Preconditioning? Just floor it to 100 and then max regen to 60. Do it over and over a few dozen times. I did this on my Kia EV6 on the way from Mammoth to Bishop EA chargers. Raised my battery temp from 40 to 70F fairly quickly.

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