Model 3 12V battery died overnight in cold

[Starvin]

My Model 3 was charged to 350km, and the 12v battery still died overnight. I'm assuming this has to do with the cold. Car was dead and unresponsive. I jump started the battery and the car seems to be operating okay now. It shows that it is charging, and the range is increasing, but the charge rate shows 0km/h. Strange. Rebooted the car, didn't fix it.

I scheduled service for the next possible date which is a month from now. Do you think the car will be okay until then? Any way to get service sooner? I also have some other problems I want them to look at. Car won't charge in the cold because the port latch gets frozen (apparently a new part fixes this). Charging port opening/closing is also unreliable. Most of the time I have to open it from inside the car.

 

[Tony_YYZ]

My Model 3 was charged to 350km, and the 12v battery still died overnight. I'm assuming this has to do with the cold. Car was dead and unresponsive. I jump started the battery and the car seems to be operating okay now. It shows that it is charging, and the range is increasing, but the charge rate shows 0km/h. Strange. Rebooted the car, didn't fix it.

I scheduled service for the next possible date which is a month from now. Do you think the car will be okay until then? Any way to get service sooner? I also have some other problems I want them to look at. Car won't charge in the cold because the port latch gets frozen (apparently a new part fixes this). Charging port opening/closing is also unreliable. Most of the time I have to open it from inside the car.

Call the service center and ask if they can setup a Mobile Service appointment for you.

 

[widodh]

Charging at 0km/h usually indicates that all power is going towards heating the battery and not charging the battery.

Just let it charge for a while and see how that works out.

 

[Starvin]

Charging at 0km/h usually indicates that all power is going towards heating the battery and not charging the battery.

Just let it charge for a while and see how that works out.

Thanks, that must have been what it was since it increased about an hour later. Never seen that before. I wish there was an indicator saying "heating batteries" or something.

 

[widodh]

Thanks, that must have been what it was since it increased about an hour later. Never seen that before. I wish there was an indicator saying "heating batteries" or something.

That would be better indeed.

I've seen this recently where my Model S100D was parked in below zero (Celcius) temperatures for 48 hours and I wanted to charge it. It stayed at 0km/h for an hour before it slowly went up.

In the meantime it was drawing ~6kW from the charging station without increasing the stated range.

Still weird that the 12V battery suddenly died. Those should be able to withstand low temps. How cold was it?

 

[Starvin]

How cold was it?

It was left in a garage unplugged for 2 nights and the average temperature was -15C. My phone was not able to connect after the second night, which is when I assume it died. I thought the 12V battery would always recharge and the car doesn't have to be plugged in.

 

[mociaf9]

If you haven't done it already, I would recommend carefully checking the 12V cables, posts, connectors, etc. If there is corrosion or a bad/loose connection that could interfere with charging/recharging the 12V battery.

 

[Vawlkus]

It could be a battery fault. Hopefully it’s not the DC/DC that normally charges the 12v, cause that’s annoying to replace.

 

[Starvin]

I had my service appointment moved to today. Here is what they said...

"Upon further inspection diagnosis, we can see that the 12v battery was reporting 7.3v at the time of the issue. This was caused by the vehicle HVC controller stuck in a sleep mode. It was also seen the bootloader was not updated which would cause this issue. Updated BMS bootloader and removed and replaced 12v battery. Performed system test to verify operation."

Hopefully this is very rare issue. But they did a great job. Cleaned car thoroughly inside and out, topped washer fluid, filled tires, replaced 12v battery, replaced latch actuator, replaced charge door magnet. All in a few hours and still gave me a rental car. All under warranty. Tesla service gets a bad rep lately, but I have had an amazing experience.

 

[MP3Mike]

It could be a battery fault. Hopefully it’s not the DC/DC that normally charges the 12v, cause that’s annoying to replace.

The DC/DC in the Model 3 is part of the battery pack. (It is in the penthouse section under the rear seat.)

 

[Vawlkus]

The DC/DC in the Model 3 is part of the battery pack. (It is in the penthouse section under the rear seat.)

Ergo, a pain to replace.