Absolutely Best, Proven Method to Warm a Cold Battery

[Jane4]

I've been wrestling with this question every winter since I got my M3 in 2019. Is it better to warm the battery by charging--timing my charge so that it finishes just before I leave? Or is it better to turn on the heat before I go? And for how long? And at what temp? Lately I have been doing a combination of all this stuff. I have my charging start at 4:30 am, but my departing/commuting time varies, so it could be a couple hours before I drive off. Not ideal? No big deal? And then I set the heat to 60 degrees for 20 minutes or so, basically to just start warming the battery, because there doesn't seem to be any other method of officially sending heat to the battery, (if charging is done.) And then about 10 minutes before I get in the car, I increase to 74 degrees just so the cabin is toasty. Then I reduce to 68. But even when I time all of this perfectly, with a long (~50%) charge, I still have many dots in the region indicator. I guess that's unavoidable? Sometimes I even increase the battery charge target a bit for the last 20 or so minutes before I leave just to heat it even more. Problem with that is that I can forget and overcharge the next day. None of this is ideal!!! Surely Tesla could come up with a less complicated solution. And yes, I have tried the Departure Precondition setting, but have been late to work because the battery wasn't even close to the set point when I needed to leave! Been hesitant to use it since then.

Please, experts, weigh in? How should I prepare my car given that I don't have a set departure time every day?

We have a model 3, 2020, long range and use the "Schedule" function religiously and then before leaving, I shut the windows and add the Climate function and kick the temp up and use the seat heat. We don't have a steering wheel heater, as far as I know. All of this seems to get the car ready. But we also don't go out in below freezing temps. We're retired.

 

[TydalForce]

Honestly I think you're overthinking this. You shouldn't wait on the battery to precondition before driving, if it's gonna make you late for work. It's okay to drive it cold, just don't floor it on every road (c:
I'd do this: Set your charge schedule as late as possible, while still ensuring you have enough charge for your commute. For comfort, schedule departure around, idk, your most common departure time - maybe a little later. If you'll be leaving early on a day, use the app to turn the climate on maybe 10-20 minutes before you leave. If you have any flexibility in where you park, see if you can park in a sunnier spot.

It's okay to drive with regen dots, just remember the regen won't be as strong and you might need to use the brake pedal (and/or enable the new "blended" feature).

 

[SpartanNYS]

First thing would be to use the phone App 'Scan My Tesla' to determine your battery cells temperature,
since this is your main worry.

Honestly, I don't think that using your home charger will create too much heat, like charging your phone.
The battery itself has its own heating management to prevent charging when the battery is below freezing.

This was not clear to me: Do you warm your whole garage to pre-heat the battery and your car,
or do you use your phone App to turn on the inside car heater?
If you can, try using a small electric heater inside your car connected to a socket in your garage to save battery energy.

I find it simpler to charge when the off-peak rate starts, so I know that the battery will be fully charged
the next morning, than to wait for the last minute, as power interruptions are possible or in case I need
to use my car for an emergency, like going to the nearest hospital or I receive an call from my work.

DO NOT use an electric heater inside your car. small, medium or Large.

 

[derotam]

DO NOT use an electric heater inside your car. small, medium or Large.

This statement with no reasons given is meaningless. Given a current electric heater with appropriate tip over sensor, and ensuring the temperature is not set too high, there would be no issue in putting on inside the vehicle.