Battery pre-conditioning?

[desLars M3]

The battery of the M3 LR pre-conditions for optimum charging at superchargers (SC).

1) Starting a longer trip via a SC, the red title 'battery pre-conditions...' appeared at the top of the nav when I had just hit the highway and the SC was still 2hrs away, it re-appeared after 1hr and re-appeared a third time when reaching the SC.

2) Once inbound to a SC, still 1hr away, I tapped on this red title to see what would happen: the message disappeared to never come back again. To force the battery to pre-condition just before reaching the SC, I had to delete the SC as destination and start a new trip to the same SC and only then the red title came back.


My questions:

is it necessary to have the battery pre-conditioned at intervals as in case (1) and is there a better way to start the pre-conditioning manually than how I did it in case (2) ?

 

[GtiMart]

The battery needs to be at 40-45C, maybe even 50C for optimal charging performance. Yes, it needs to precondition to reach those temps, that will never happen during driving unless you're on a track gunning it constantly.
The preconditioning method has changed compared to last year. Now, it generates a bit of heat in the motors, just a few degrees over the current battery temp, and circulates that into the battery. When the temp difference is low, it starts generating a bit more heat in the motors and that cycle continues as you drive to the SuC. The red message only appears when the car is actively spending energy to generate heat, The rest of the time, that heat is circulated (e.g. preconditioning continues to happen) but with no energy waste.
EDIT: 2 hours away is common now, a lot of people have reported it. Batteries are huge masses and take a long time to change temperature. Don't worry.
Last year, the process would start much later and the car would constantly generate heat in the motors, going over 100C. That process was probably less efficient, and harsher on motors and the battery, so they changed it.

Don't click on the red text if you don't want to stop the process. That's what clicking on it is for, and I believe the car does tell you on screen.

 

[tstolze]

The battery of the M3 LR pre-conditions for optimum charging at superchargers (SC).

1) Starting a longer trip via a SC, the red title 'battery pre-conditions...' appeared at the top of the nav when I had just hit the highway and the SC was still 2hrs away, it re-appeared after 1hr and re-appeared a third time when reaching the SC.

2) Once inbound to a SC, still 1hr away, I tapped on this red title to see what would happen: the message disappeared to never come back again. To force the battery to pre-condition just before reaching the SC, I had to delete the SC as destination and start a new trip to the same SC and only then the red title came back.


My questions:

is it necessary to have the battery pre-conditioned at intervals as in case (1) and is there a better way to start the pre-conditioning manually than how I did it in case (2) ?

I noticed the same thing on a recent trip, preconditioning started 2+ hours from the Supercharger as soon as I departed, once the battery was at the desired temperature, preconditioning cycled off/on to maintain that temperature until I arrived.
Seems like a waste of energy to maintain the battery at 120°+ for long periods.
Traveling in the Spring and Summer of this year preconditioning would start 20-30 minutes prior to arrival.

 

[GtiMart]

I explained it in my post. The car now heats the battery gently, which takes a long time, instead of pushing 100C fluid in a 20C battery. In any case it takes a long time to heat a 1000lb+ battery. I would bet the new process is less wasteful than previously. Having motors at 100C+, there would certainly be a lot of loss to the ambient air around them. The change was done for a reason. Even if it's just for longevity of the motor circuitry, I welcome it.

 

[Gasaraki]

The battery of the M3 LR pre-conditions for optimum charging at superchargers (SC).

1) Starting a longer trip via a SC, the red title 'battery pre-conditions...' appeared at the top of the nav when I had just hit the highway and the SC was still 2hrs away, it re-appeared after 1hr and re-appeared a third time when reaching the SC.

2) Once inbound to a SC, still 1hr away, I tapped on this red title to see what would happen: the message disappeared to never come back again. To force the battery to pre-condition just before reaching the SC, I had to delete the SC as destination and start a new trip to the same SC and only then the red title came back.


My questions:

is it necessary to have the battery pre-conditioned at intervals as in case (1) and is there a better way to start the pre-conditioning manually than how I did it in case (2) ?

The car knows more about what's best for itself. It doesn't need to be babied with everything. If it thinks it will take 2 hours to precondition, let it. It will stop preconditioning if it no long thinks its necessary.

 

[rexki]

Can you pre-condition the batteries before departure while plugged to L2 charger at home?
That way you would use the energy from the house/grid instead of pulling it out of your battery capacity and thus reduce range.

Maybe just cabin temp warming gets good percentage of the battery heating?

 

[GtiMart]

Conditioning the cabin does heat the battery if it's very cold. However it won't reach the same temperature. Last year it would stop at 20-21C but this year it's lower. I haven't done enough testing to know the precise value yet but I believe it's somewhere in the 5-10C range. It provides some regen when you start driving. Clearly not hot enough for supercharging.

 

[rexki]

Conditioning the cabin does heat the battery if it's very cold. However it won't reach the same temperature. Last year it would stop at 20-21C but this year it's lower. I haven't done enough testing to know the precise value yet but I believe it's somewhere in the 5-10C range. It provides some regen when you start driving. Clearly not hot enough for supercharging.

I will take my charge limit up (Home L2) from standard 80% to 95% and that should leave capacity to run pre-conditioning on my trip tomorrow on the highway south of Chicago - temp expected to be 39F with a 12-18 mph headwind and 120 miles each way - highway speed limit 70. Planning on 264-270 wH/mile window round trip. Destination will be a target 48F temp and may try the Normal IL Supercharger - apparently there was a fire back in September 2021 that shut it down for weeks.