The power-off option from the menu hasn't resulted in a HV contactor click in over a year. Could this be because the 12V battery in my July 2018 M3LR is slowly going bad?
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could dying 12V battery be the reason HV contactor doesn't disconnect on power-off?
- Thread starter smatthew
- Start date
Probably not. I’m not intimately familiar with how Tesla wired the main contactor, but it’s just a big relay - when 12v is applied to the coil, the contactor closes. When there’s no 12v, it opens. So, if there’s a 12v failure the contractor will fail in a safe way, with no 400v available.
I just tried it on my car-no contactor clunk on shut down. The interesting thing is that the car is still accessible from the app, the charge port responds to the charging cable button, and the doors open. I guess I’m not sure what “shutdown” actually shuts down.
I just tried it on my car-no contactor clunk on shut down. The interesting thing is that the car is still accessible from the app, the charge port responds to the charging cable button, and the doors open. I guess I’m not sure what “shutdown” actually shuts down.
Power off
Shutdown
Go to Sleep
The terminology is confusing.
Which, if any, mean the contactor is opened?
And how do you tell if the contactor is open? So far I've just been told to wait 30-45 minutes and listen for the clunk.
But apparently there are some programs that report when the car is "asleep". Does that mean the contactor is open?
If so, the program, and the car's monitors, must be running off the 12V battery alone, as the DCtoDC converter wouldn't work.
Shutdown
Go to Sleep
The terminology is confusing.
Which, if any, mean the contactor is opened?
And how do you tell if the contactor is open? So far I've just been told to wait 30-45 minutes and listen for the clunk.
But apparently there are some programs that report when the car is "asleep". Does that mean the contactor is open?
If so, the program, and the car's monitors, must be running off the 12V battery alone, as the DCtoDC converter wouldn't work.
Any of those apps that report the car is asleep have to pause in their data collection to let the car sleep, and dont report any information during that time.
"Power off" is like a shutdown on a computer, but the car does not go to sleep immediately when you do that. I never have heard the contactors either when using the power off command in the menu, and have never sat out in the car to wait for it. It takes a few minutes for that to happen is my understanding.
I power the car off after every update, and let it sit until I need to use it again, whenever that is.
Power off = use the power off command in the menu
shutdown = I dont know, there is no mention of shutdown in the tesla manual nor any shutdown command. If you are seeing this, its likely somewhere online with someone using that term.
go to sleep = car in a sleep state, which typically happens in 10-15 minutes as long as something is not keeping the car awake, like sentry mode, climate overheat protection with AC, or any connections to the vehicle either from the tesla app or third party apps.
On my 2018 Model 3 shutdown has never opened the contactors (put the car in sleep state). If I need to do something to the car where sleep state is required, I pull the negative cable from the 12V battery post then unlatch the black connector located under the rear seat passenger side. You can also wait until the car enters sleep state then you only need to lift the cable from the 12V neg terminal. Tip: Roll all the windows down before doing the above or you will not be able to enter the cabin.
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