Do you guys always precondition before charging?

[AAKEE]

Is that based on your logging or do you have another source?

I'm asking because I have an LFP battery, and in my climate (overnight temps typically 1-3C), there is a massive observed difference in regen with preconditioning. Maybe 5C makes all the difference, or maybe LFP is heated differently?

Having said that, even after preconditioning, there are still dots on the regen display, and sometimes a "regen limited" icon on the side.

I have a few logs from today to show, *made specifically for you*

I had the MSP outside overnight because I had a rental trailer connected to it.
I did set the preconditioning time to 10:30 one hour before (set up was done 0933, when walking the dog. The car woke up as we walked beside it with the dog at 09:33. Cell temp was 3.25C according to the log. (-1C outside at home at that time).
I let the car stand 20 min extra from the set time to show the cell temps evolves during a preheting session.
As we can see in the red boxed area, no "battery heating" is logged. The battery heating is only shown in the log if it was on during the time frame.
There was no battery heating done.

When I entered the car and drove away at 10:50 the cell temp was 4.25C and the cabin nice and warm (I did get the usual notice from the app 15 minutes before the set time that the cabin has the desired temperature).

For some reason the cell temp doesnt have logs after 10:36, thats not normal but must have something to do with SMT/teslalogger.
Returning home without the trailer the cell temp was 5.0C and I spefically made a few regen sessions from a little higher speed, and the regen was more or less normal, just slightly less than with a warm batt.
If the battery had been below freezing (or actually below about 3C) and without preconditioning there had been no regen at all until the cell temp had reached 3C. The car would automatically have run battery heating until the cell temp hade reached 3-4-5C and the regen would com on at about 3C.

Of course this is different with the LFP cars, as the LFP batteries are much more sensitive to being cold, but to have an idea how ot works on this cars and for other to read about it, as battery heating is very common in the battery myths.

It is possible to see the battery heat in another view of the logs: No active battery heating was done.

 

[toolman335]

You guys are splitting atoms a bit. There are many specific reasons for each of us to handle these situations differently.

I have a 9 mile commute in a very cold climate. I've had people tell me that I'm insane that I didn't burn energy for 30 minutes preconditioning the battery and warming up the cabin. Umm.....yeah, I really need to maximize my energy consumption for my 10 minute commute.

 

[AAKEE]

You guys are splitting atoms a bit. There are many specific reasons for each of us to handle these situations differently.

I have a 9 mile commute in a very cold climate. I've had people tell me that I'm insane that I didn't burn energy for 30 minutes preconditioning the battery and warming up the cabin.

Unless the car is outside in really cold and not charged the battery is mostly not heated even if you do a preconditioning of the cabin.

Umm.....yeah, I really need to maximize my energy consumption for my 10 minute commute.

 

[alexgr]

Is it necessary to precondition for charging at home? Is it even possible? Or just for going to superchargers? And is it important to precondition before you drive everyday even if it's not cold or hot outside?

no. maybe. sure. yes, you can.

 

[classychris92]

Yes, logging and also have a tablet with scan my tesla in the car all the time.
On my M3P I had it mounted in front of the steering wheel. I did see the cell temp live continuously. (On the MSP it is in the center panel).

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There is a big difference in regen as lithium batteries must not be charged below 0C and tesla do not allow regen if the cell temp it about 3C or below on the LR/P packs.
The battery warming put it on the right side of the limit.

I haven’t checked any LFP car with SMT car for regen at cold temps but I know they are more “sensitive” for cold and low temperatures so no- or low regen are more common with LFP cars.
I do not know to what temperature tesla heats the battery when preconditioning a LFP but I know for model 3 LR/P and model S 2023.

Yes, you’ll se that during the winter.
Regen limit is affected by SOC as well, not only cell temperature, low SOC is less restrictive.

Are those apps? And can I use them of are they expensive? Cause logging and checking degradation sounds great

 

[AAKEE]

Are those apps? And can I use them of are they expensive? Cause logging and checking degradation sounds great

Yes, Scan My Tesla is an app.

Needs a few part of hardware so not very cheap in total, but not very expensive either.

On model 3/Y you can check the battery capacity with the energy graph for free.
Its easy and info about how to do it is found hete on TMC.