8-month-old car, 12V battery needs replacement

[teethdood]

As the title says, my almost 8-month-old car just displayed a warning to replace the 12V battery. That's the fastest battery degradation I've ever seen in my cars. I just came back from a 10-day vacation, so I'm not sure if that has anything to do with the battery. The car was plugged in the entire time in the garage.

On a related note, who is responsible for its replacement considering it's only 8 months old? I live 200+ miles away from a service center, do you think Tesla will send a ranger out to me? Thank you and happy holidays!

 

[Tam]

...8-month-old car...

That's an expectation for changing BMW 12V battery every 10,000 miles as well.

If your car is not dead, it's your responsibility to bring it to a service center.

If it is dead, it's Tesla's responsibility to get yours working again.

Call Tesla up. It may arrange free Ranger Service if it needs to go to your remote area for other owners as well.

 

[Buook]

12V battery should be charging with the high voltage battery while the charger is plugged in, no? Something is wrong

 

[Tam]

12V battery should be charging with the high voltage battery while the charger is plugged in, no? Something is wrong

12V battery is automatically recharged as needed whether your Tesla is plugged in or not.

As mentioned on the article above, it's a norm for modern cars whether ICE or EV to replace 12V much more frequent than the good old days because of heavy usage demands.

 

[Buook]

I just read that BMW 10,000 mile battery article. That is not common nor acceptable to replace a battery every 10,000 miles. It specifically states in the article that BMW came up with a new technology that stops charging the 12V much in an effort to improve gas mileage slightly. This obviously causes the battery to discharge cycle much more frequently which is terrible for automotive batteries. I wouldn't say that its now the norm just because one article points out BMW's bad tech.
Heavy usage doesn't degrade battery life if your alternator is working correctly in an ICE.

 

[teethdood]

@Tam
I read the article but it's about a BMW and its twin turbo engine needing to be cooled long after the engine's been off, so charge/discharge cycles eat up batteries. Teslas obviously don't have twin turbo charged engines. Did you or anyone else had to replace your 12V after ~10K miles? You're right that my car is approaching 10K miles. I just want to make sure that I'm within the norm.

 

[skilly]

Im pretty sure that its covered under the initial factory warranty. Mine in a previous MS went bad about 20000 miles and 2 years in and they replaced it free of charge.

 

[Tam]

...I just want to make sure that I'm within the norm.

For ICE:

12v Battery Failures up 40% in ICE cars! | Tesla

For Tesla, many have no problems with 12V battery but if you do, you are among numerous reports of 12V battery failures that are not unheard of:


Submitted by Anthony J. Parisio on December 22, 2014
Hi all! Just got my 12V battery replaced today. It only took 1 and 1/2 hours. Naturally I was puzzled that a 10 month old car with 9,100 miles on it would need this battery so soon. So I nicely grill the Service manager about it. What I got from our conversation is this, the 12V battery is used very differently and for different reasons in a Tesla than in a Fossil car....


jeng95630 | November 14, 2017
I just had my 12V battery replaced by Tesla mobile service today (11/14) on a S75D. 11 months and 11K miles.



A Tesla ranger in 2014 was reported by Speedy P | November 2, 2017 as:
"doing at least one battery swap each time he went out."


nbrianjohnston | January 19, 2015
I got the 12V warning on my car yesterday. My car is March 2014 model and I'm at about 19,000Km. Called the local SC this morning and a ranger is coming today at 1PM to change my battery. THAT is is service.

 

[Tam]

There's a poll at:

POLL: Have you had to have your 12V battery replaced?

12V battery replacement AND repeated replacements are not that rare as I would expect from my previous ownership of my much older cheapo ICE cars.

What I am saying is: It can happen so plan appropriately and don't be caught off guard!

 

[teethdood]

Tam, thank you for looking up old threads. I tried searching for 12V battery problems but obviously I didn't search hard enough. I just replaced my minivan's battery at 48 months and 50K miles this past weekend, so I was very surprised to see my Tesla's 12V battery warning today, and the stats are eye-opening for sure. One of Tesla's motto is "sustainable living"; it's taken a hit in my eyes somewhat with having to replace a 12V battery every 10K miles. In addition, it's not a simple DYI battery swap like an ICE car. Still love my tesla though.

 

[Rxalset]

Can’t wait until they can solve this dependency on the 12 volt battery.

 

[vandacca]

Can’t wait until they can solve this dependency on the 12 volt battery.

Maybe installing an electron scoop dish on the front to capture free ions while driving?

 

[AnxietyRanger]

My 12V on the Model S had to be changed after less than a year too - one of those things with a Tesla.

It didn't die or anything, just prompted an error, Tesla swapped it under warranty and that was that.

 

[ChrML]

Maybe installing an electron scoop dish on the front to capture free ions while driving?

Haha.

But why can't the electronics be connected directly to a DC-DC converter from the main battery?

 

[vandacca]

Haha.

But why can't the electronics be connected directly to a DC-DC converter from the main battery?

I think for safety reasons (and possibly to prevent drain), the main battery has safety relays that are turned off in various scenarios. For example, if you are parked for a long time, the main battery is disconnected and the vehicle runs off the 12v. When 12v battery gets low, the main battery is connected again and it recharges the 12v, then disconnected again.

When you wake the car up, you'll actually hear a loud click, which I believe is the main battery being engaged.

 

[Tam]

...But why can't the electronics be connected directly to a DC-DC converter from the main battery?

This was covered many times as original Roadster (less than 2.0) took your advice and did not have a separate 12V battery which resulted in very bad press:

Tesla Battery Failures Make ‘Bricking’ a Buzzword

Roadster 2.0 and later has not taken your advice anymore and started to have a separate 12V battery.

There have been complaints about 12V battery failures but absolutely no bad press on this battery subject since then.

 

[Epymian]

Lol 12 v battery.

I just got a "Battery Failure Warning Avoid hard acceleration" on my dash display and the SC says I need the entire 90 KW pack replaced. I am at 18,000 KM and 18 months ownership. The car drives normally so far and I assume I will make it across the mountains 400 km to the SC when the new battery arrives. Hopefully the replacement is quick.

I asked if I could upgrade to the 100 KW since replacing anyway but apparently my VIN does not qualify. Did not know there was a restriction for early VINs (75xx).

 

[Tam]

...Hopefully the replacement is quick...

They'll get you back to driving quickly but usually, they'll let you temporarily use a battery loaner while fixing yours for a few months in Fremont.

 

[Kacey Green]

I hope they get off this 90 not qualifying for an upgrade nonsense. Are we going to skip over 100 as the tech improves or are we stuck with 90 and they stuck with maintaining 90s for the full duration of our warranties?

 

[Kacey Green]

I wouldn't be surprised if one of us gets a software limited 100 sometime in the next 4 years, especially if the 90s keep self destructing or having accelerated degradation