Preconditionning takes for ever

[Maverick1100]

My information:
- 2022 Model 3 RWD (LFP)
- I charge to 100% every night

Last night I set my car to precondition and be ready for 6am. At 5:48am i got a notification that my cabin was at my desired temperature. (ok 12 min early but fine) When I got in the car this morning at 6:20am it was 10C (50F) and I still had 15 dots to the left of my brake/regen bar when I left my driveway. After driving 15km (9.3 miles) finally all my dots to the left of my brake/regen bar disappeared.

I have experienced this behaviour 3 times now. (once a week for the last 3 weeks)

Question 1: why can't the car correctly determine the time to warm up? After 3 times there should be some sort of calibration.
Question 2: Why doesn't the car full precondition by the time it was set?

I am doing something wrong or are my expectation misaligned?

 

[GtiMart]

You will have dots on the regen if you are charged at 100%, whatever the temperature of the battery I believe. Even on LFP if I am not mistaken. There is nowhere for the car to store the energy recuperated in regen, your battery is full.

 

[DeltaOne]

Last night I set my car to precondition and be ready for 6am. At 5:48am i got a notification that my cabin was at my desired temperature. (ok 12 min early but fine)

I don't use Scheduled Departure often, but the car typically says it's charged and preconditioned 15 to 30 minutes before the time I set.

I don't worry about it, but it does seem like an odd thing for the computer to do.

 

[Big Earl]

You will have dots on the regen if you are charged at 100%, whatever the temperature of the battery I believe. Even on LFP if I am not mistaken. There is nowhere for the car to store the energy recuperated in regen, your battery is full.

Yep. In addition, preconditioning won’t heat the battery enough for full regen even at lower states of charge.

Heating the battery is mostly a waste of energy. It takes more energy to warm the pack than you gain back from the additional regen. This can be beneficial if you’re about to set off on a long trip, but not for daily driving.

 

[GtiMart]

You're right @Big Earl , since last year preconditioning doesn't heat the pack as much as it did two years ago. It stopped around 7C and would continue to raise as it finishes scavenging what's left in the motors, would settle maybe at 10-11C? That was enough for 50kW of regen, out of a maximum value of 85kW on a dual motor. Good enough without being too wasteful, compared to before.

 

[Gauss Guzzler]

I don't think there's any real benefit to charging to 100% and I don't understand why Tesla recommends it so strongly. Seems like 98% would be much better as it allows some room for regen and therefore reduces energy consumption and brake wear.

But regardless, OP may want to enable the new brake assist option for limited regen conditions to at least provide consistent deceleration behavior.
"Controls > Pedals & Steering > Apply Brakes When Regenerative Braking Is Limited"

 

[GtiMart]

LFP batteries are much harder for the BMS to properly figure out the capacity and current charge. TeslaBjorn just posted a video on Youtube where he runs it down to zero on a new car. He doesn't get the typical power limit down low, and he burns over 6kW after 0% which is not what the buffer is supposed to be. Charging to 100% "at least once a week" as Tesla suggests probably helps that. I suspect that running down low regularly probably also helps but that is not the official statement because it would appear as too complicated for owners.

 

[Maverick1100]

Thanks for all the information. I will try to only charge to 98% and have precondition. I'll see what that gives me.

@DeltaOne, I have seen the message for the cabin is at the desired temperature but I have never seen a message saying the battery is finished preconditionned.

 

[DeltaOne]

@DeltaOne, I have seen the message for the cabin is at the desired temperature but I have never seen a message saying the battery is finished preconditionned.

If I remember correctly the messages say the cabin has reached its set temperature and the battery has finished charging.

The only battery preconditioning I know of is when you have set a Tesla Supercharger as your destination. The car will precondition the battery so that when you arrive at the Supercharger it can charge at a fast rate.