Welcome to Tesla Motors Club
Discuss Tesla's Model S, Model 3, Model X, Model Y, Cybertruck, Roadster and More.
Register

12 volt battery, replace now or wait for warning?

What to do about 12 volt battery?

  • Replace ASAP

    Votes: 14 33.3%
  • It will give you a warning, get a few more months out of it.

    Votes: 19 45.2%
  • Elon's coming to rescue the battery, leave it in.

    Votes: 6 14.3%
  • Do the Kramer!

    Votes: 3 7.1%

  • Total voters
    42
This site may earn commission on affiliate links.

iwannam3

Active Member
Aug 8, 2016
1,076
1,452
Washington
April 2018 15K VIN 23K miles. I see all the reports of failures and confusion about the battery, AGM, deep cycle, LI, and where to get it. Bought across the counter for $85 at Tesla. No core charge! with all the bullets flying lead had gotten more valuable, but maybe they don't want dirty leaking hazardous material to deal with.

Battery is 10 feet away from car, replace now in the garage on my schedule or do a Krahmer and run it till it stops?

Of course Elon says not to worry, software update coming.
Expect more from the 12V battery in your Tesla soon: Elon Musk - Drive Tesla Canada
 
Our 3's battery lasted about 18 months and the car was instantly very flakey when it went. Batteries go quickly in the Arizona heat, but that was a record short life for us. The 12V warning was coincident with the problems. We were able to drive to the SC, after many resets one finally worked well enough after a day.

I'd carry the battery in the car, with enough tools to install it. That should ensure you get the two week warning.

If it's being driven by a non-handy car person I'd install it now.
 
  • Like
Reactions: Ciaopec
I replaced my OEM battery last month. My rationale is that if it were too fail without warning, the hassle of getting towed to the Service Center would make the cost of the Ohmmu battery seem really cheap. Yes, the car is still under warranty for another 5,000 miles, but reliability is just more important to me than the cost of a new battery. Plus, I had a use for the old battery so I keep that on a battery tender for use when I'm I work my honeybee hives and treating for mites.

I would recommend you think about how you'd feel about deferring the replacement when you or your significant other is stuck with a bricked car in a parking lot, trying to get a hold of roadside assistance. To me, the frustration just wouldn't justify delaying the inevitable.
 
Battery is 10 feet away from car, replace now in the garage on my schedule or do a Krahmer and run it till it stops?

Of course Elon says not to worry, software update coming.
Expect more from the 12V battery in your Tesla soon: Elon Musk - Drive Tesla Canada

If you have a replacement battery why wait? Do it when you have time & in a warm, dry & well lit place of your choice like a Tesla Service Center or by a mobile ranger. I’ve worked on my cars. EV’s are different. A mistake can be expensive.

My 12v died unexpectedly ( sort of) and had I heeded the warnings I could have saved a $400 tow and a lot of aggravation. What is the upside of waiting? What is the downside of doing it now?
 
I guess it depends on your situation. Are there days where when you get in the car you absolutely have to leave right then and there for something super critical and can't afford to wait the 1-2 hours it would take to change the battery, then I would do it now. If your life is more relaxed and there basically wouldn't ever be that situation or if you have an alternate car you could drive that day, then maybe wait. That's my advice.
 
If you have a replacement battery, you better have it on a float charger. Otherwise when you need it you are going to have two dead batteries. Lead acid batteries don't like to sit without a charger on them. They will sulfate up and die if they sit too long, especially in a hot garage.
 
  • Like
Reactions: NickFie
Mine died without the warnings also. Lasted about 19 months. Unless we actually see a way to monitor the 12v battery and better warning I will replace mine prior to month 19 again. They are not that expensive and its better than the headache if it does die when you need it most.
 
I'd change it, then put the old one on a good float charger, to keep as the emergency backup. $85 is cheap insurance. So what, it should be on Tesla's dime. Having the aggravation of the car dying somewhere, then having Tesla come tow it, is way more costly than spending $85 and replacing it.
 
I use a CTEK monitor (Battery Sense). https://www.amazon.com/CTEK-40-149-CTX-Battery-Sense/dp/B0188TGF6W/ref=asc_df_B0188TGF6W/?tag=hyprod-20&linkCode=df0&hvadid=312844081654&hvpos=&hvnetw=g&hvrand=8400407084339103294&hvpone=&hvptwo=&hvqmt=&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=9031309&hvtargid=pla-587373986114&psc= and check it everyday. It's always 13V+ (today it is 13.56V, in my 2018 model 3 with 13K miles. Won't this alert me to a failing battery if, and when, the voltage begins to drop? I always "disable climate" and car always goes to sleep.
 
Mine died without the warnings also. Lasted about 19 months. Unless we actually see a way to monitor the 12v battery and better warning I will replace mine prior to month 19 again. They are not that expensive and its better than the headache if it does die when you need it most.
I'm wondering if those who had these 12V warnings or errors or having the battery die, anyone check with a voltmeter? Maybe that's a routine thing I can do to keep check on the status.

Just googled. Since 12V are ubiquitous in ICE
Screenshot_20201122-093352_Chrome.jpg
 
  • Like
Reactions: Blu Angel
Personally, I'd replace it right now.

If the battery degrades naturally over time (as it's supposed to), then yes, you'll get the warning in plenty of time to replace it.

The problem is that if you check out all of the various Tesla related forums/subreddits, you'll find a discouraging amount of people posting about how their 12v battery failed without any prior warning at all.

IMO (gathered from way too much time spent reading Tesla related content), the OEM battery supplier for the Model 3 has put out at least one bad batch of batteries. Rather than gradually degrading over time as a good lead/acid automotive battery should (and failing in this manner is detectable by the Tesla's software), they just outright fail. No prior warnings, nada... just a completely dead battery.

When I finally get around to replacing mine, I won't be replacing it with the exact make/model that Tesla used from the factory, as I don't want to run the chance of getting yet another bad battery from a manufacturer that, up to this point, hasn't owned up to the fact that they have a large amount of bad from the factory batteries.

FWIW, the battery in the Model 3 is a bit different from standard ICE batteries; the Tesla uses a "Deep Cycle" type battery. Might be worth spending the additional time/research needed to make sure the battery you get is an exact match.
 
  • Like
Reactions: PhysicsGuy