12v Battery Alert

[Apprunner]

interesting piece here, I have 12v warning message for over 2 months now, the car goes to sleep normally. Can obviously see losing 10km or so every morning, seems like the car is trying to keep 12v topped up.

How do you know its asleep? I could tell its awake when I open the app up and get immediate response from the app. I lost about 5% every 24 hours with the 12V battery alert. I typically lose about 1% a week when my car is asleep.

 

[UncertainTimes]

interesting piece here, I have 12v warning message for over 2 months now, the car goes to sleep normally. Can obviously see losing 10km or so every morning, seems like the car is trying to keep 12v topped up.

You like to live dangerously

 

[S&B's M3]

So a ranger came out and swapped out the battery, no more issues or alerts thus far.

 

[DonTom]

I have a 2018 Tesla M3, LR, AWD. I have a few questions about the 12-Volt battery.

A year ago or so, I replaced the lead acid 12V battery with a Ohmmu lith battery.

I live in two different houses, and I am often 100 miles away from my Tesla for a month or so at a time. I leave the Tesla on my Tesla Wall Connector to keep the HV battery just below 80% SOC.

When I come back here to my Tesla, I always have the "schedule to replace the 12-volt battery" message. It's been very cold here lately if that is a factor. I didn't have this issue in the summertime.

I just now powered down the car, unplugged the charging and measured the voltage on the 12-volt battery. still connected normally. It measures 12.48 volts.

1. Is 12.48 volts low enough to get an alarm?

2. Is there a way to reset the "schedule to replace 12-battery" message without disconnecting it and the HV? I know if I go through the procedure as if I were going to replace the 12-volt the message will be gone until the next time I leave for a month.

3. Does the 12-volt battery charge while I am charging the HV battery? I would think it would. So why does this happen?


-Don- Reno, NV

 

[Rocky_H]

So why does this happen?

Well, this question and all of your other questions are answered by this:

I replaced the lead acid 12V battery with a Ohmmu lith battery.

The car's algorithms for sensing, detecting, and charging are all programmed to the expected behavior of a standard battery. The lithium type has some different characteristics that doesn't behave like that, so the car sees weird behavior when it tries to deal with it and thinks something is wrong with it. That's always going to be a problem.

 

[DonTom]

The car's algorithms for sensing, detecting, and charging are all programmed to the expected behavior of a standard battery. The lithium type has some different characteristics that doesn't behave like that, so the car sees weird behavior when it tries to deal with it and thinks something is wrong with it. That's always going to be a problem.

Thanks for the reply. It's not that much hassle to reset the battery, so I will just live with it. But I wonder now if I should have just kept with the lead acid 12V battery.

This is what I do when this happens. Only takes about ten minutes or so (please let me know if there is a better way or better order to do this):

1. Open all windows, trunk, frunk, all four car doors.
2. Be sure is in Park.
3. Turn off climate control so there is no temperature shown.
4. Powerdown vehicle in "Safety".
5. Seat unlatches from lower cushion in middle of each rear seat.
6. disconnect 12V battery neg cable,
6. Remove HV connector under back seat passenger side. Down on latch, lift up on gray.
7. reconnect 12-volt battery negative.
8. reconnect HV plug.
9. May still have a message about no power for about 30 seconds that
should disappear on its own.

So far, above has been working for me to get rid of the replace 12V battery message.

-Don- Reno, NV

 

[DonTom]

When I do have that message that I have lost backup power and some things will not work, does all my 12V stuff still work normally, or is the message true just because of the error, even though the 12V battery voltage is near normal?

-Don- Reno, NV

 

[S&B's M3]

How do you know its asleep?

Probably heard it snoring... Afterall, it farts

 

[DonTom]

Well, this question and all of your other questions are answered by this:

The car's algorithms for sensing, detecting, and charging are all programmed to the expected behavior of a standard battery. The lithium type has some different characteristics that doesn't behave like that, so the car sees weird behavior when it tries to deal with it and thinks something is wrong with it. That's always going to be a problem.

I just found this message here. But it looks like my Ohmmu battery is too old to have the Blluetooth, so I guess I will have to stick with my old way.

-Don- Reno, NV