smatthew
Active Member
Don't you know, two data points makes a rock-solid conclusion.
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12V Battery Failure Experience
- Thread starter birjman
- Start date
Jdcorbitt3
Member
My experience with about 10 other Teslas. Prior to this, All the Teslas have given us a warning that the battery was failing. The two of us, after doing a software update, have the same failure, with no warning. Then I jumped my battery, and left the driver’s door open for about an hour. This kept the DC to DC convert running to charge the 12V battery. Later that day I drove it around the community. The “replace battery soon” message displayed until they replaced the battery.
Therefore, the “replace battery soon” message functions properly. I have to conclude that my battery drain was overnight where the car was not awaken. The neighbor went several days without driving. He did not know how to jump start his to get it online again.
I am sure more data points will be showing up soon enough.
XLR82XS
D M C
You can. Disconnect terminals, remove battery, install new battery. Instructions really not needed for anyone with any car aptitude.
lUtriaNt
Member
https://34c9c8a1-7edd-4e5b-8d85-78f...a10dd8bd324d1bb3b0537bf065ea86.pdf?index=true
these (upgraded for the model 3) instructions state you have to disconnect the HV cables under the rear seat. a bit different story than this jan 2019 produced video....
EDIT: reached out to this company to inquire and they state doing this additional procedure is mainly for the DC DC circuitry to properly "re learn" the new battery. a small percentage of cars were showing a "check 12v battery" alert and doing this procedure would rectify that. i asked why it was not included in the 2019 video and they simply stated they learned about this over time and that is why the updated install procedures were added. they also said if you did not have the alert you may not need to do this step.
After all that, the install is at least easy, but ill need to give this more thought. love the benefits gained.. tough call..
these (upgraded for the model 3) instructions state you have to disconnect the HV cables under the rear seat. a bit different story than this jan 2019 produced video....
EDIT: reached out to this company to inquire and they state doing this additional procedure is mainly for the DC DC circuitry to properly "re learn" the new battery. a small percentage of cars were showing a "check 12v battery" alert and doing this procedure would rectify that. i asked why it was not included in the 2019 video and they simply stated they learned about this over time and that is why the updated install procedures were added. they also said if you did not have the alert you may not need to do this step.
After all that, the install is at least easy, but ill need to give this more thought. love the benefits gained.. tough call..
Last edited:
I didn’t have to do that step to replace my oem battery with the Ohmmu battery last year but I did do a shut down from the screen with windows down and one door open.
Here’s those same instructions from Mountain Pass Performance:
Tesla Model 3 Hard Reset | Mountain Pass Performance
Fred
Here’s those same instructions from Mountain Pass Performance:
Tesla Model 3 Hard Reset | Mountain Pass Performance
Fred
Here’s a thought. How about if you connected a 12v source to the vehicle’s cables before disconnecting the 12v battery cables. Then, disconnect the battery, replace it, reconnect the vehicle cables to the new battery. Finally remove the temporary 12v source. That way the vehicle never looses it’s 12v source. Thoughts?
Jdcorbitt3
Member
I drove my car the night before the failure. When I powered it up, the car wanted to do another software update after the battery was replaced. I suspect Tesla pushed a mandatory update, as the car did not ask for my permission to do that update. My car has been fine since. I have gone 24 hours without it plugged in, as well as plugged in. Both cases, when powered up it was fine.
Yeah, but I wanted to take advantage of the covid deal at ohm. Only if they last in storage though?
Also batteries don't last in our AZ heat to warranty standards. I would get them replaced routinely under warranty. I wonder if Tesla 12 V will be the same
This reminds me I have to figure out Sears Diehard warranty now that we only have franchise homestores here.
lUtriaNt
Member
for some of us, its a regular day and we gotta head in to the office.
I get to work from home. It's like a dream come true. I could have always worked from home, but the company prefers we go into the office. I'm loving it. My house is like a resort. I was on a conference call this afternoon from the pool.
On the flip side, company is losing business. Shortfall of about 100 million and they plan to take it out of contractors and cutting projects. So this is about to get ugly, real fast.
My 2018 August build has been acting up over the past few weeks with a service apointntment in a week. Tesla does not provide a human to talk to or answer any of my text questions but I'm fairly certain the 12V is failing. Car is at 27k miles in Houston TX heat. This thread convinced me to advise the boss lady that she might get stranded. I'm on repair number 8 for a car less than 2 years old.
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