12V Battery Replacement

[AcuraDude]

Has anyone seen or replaced the 12V? While it looks easy, I did see a video of a wrecked Model 3 where the guys had to get under the car to gain access to a bracket bolt near the bottom of the 12V. If that really is the case, that'd mean needing to jack up the car and remove that carpet paneling on the bottom.

My service center guy told me the battery itself is a deep cycle battery and while it is not tough to replace, it may not be quite as easy as it appears.

Also, is there an aftermarket battery that fits? I haven't been able to find anything, except this lithium ion one which is like $500.

https://www.amazon.com/12V-Lithium-Battery-Tesla-Model/dp/B07K4SCB1Y

 

[jkdman123]

Saw this battery being put into an M3 on the video that showed the 1 year maintenance checks.

Any tangible benefit (other than weight) to using a 12v lithium?

 

[Adam3]

Curious about this as well. Where do we purchase normal non-lithium 12V replacement?

I believe the OEM battery is AtlasBX Model 85B24LS (?)

 

[ElectricLove]

If you saw someone go under the rear seat during install of 12V battery it wasn’t for a bracket/bolt, it would have been to unplug the HV communications header which is located on passenger side. Unplugging that shuts down the High Voltage battery, it becomes completely disconnected. This is a good idea to do whenever servicing a Model 3 and is generally necessary when swapping 12V battery out in order to reset the DC/DC converter. If that step isn’t done it’s entirely possible that your “replace 12v soon” service message doesn’t automatically reset and go away after swapping 12V battery for a new one.

There is now an easier way to do this reset tho! In V10 software they added a wheel configuration tool, when you change your wheels to a different configuration using that menu it causes a full reset of all computers on the car. It is no replacement for the safety aspect of unplugging that connector to disable HV battery during servicing of vehicle BUT it does take care of the service alert messages.

The Lithium 12V from Ohmmu is the way to go for sure and it’s cheaper on their website directly vs Amazon. Lead Acid batteries are just doomed for premature failure and frequent changes in these vehicles. It has to do with the way the 12V battery is used (cycles a LOT), not ideal for Lead Acid, however Lithium, specifically Lithium Iron Phosphate (LFP) is the best chemistry for this application!

We run Ohmmu in our X and S!

 

[mattack4000]

Doesn't lithium ion phosphate have issues in cold temperature? I don't think they are a good idea for cars that have to go into the snow due to the low temperature cutoff. The car will insulate it somewhat, but not enough to go below I think 30F

 

[markap77]

I'm just curious, but what is the weight difference between the stock battery and the lithium replacements? The Ohmmu website says their battery only weighs 11 pounds.

 

[iwannam3]

Have there been a lot of 12v failures on the 3? It is an issue on S & X.

 

[jkdman123]

I'm just curious, but what is the weight difference between the stock battery and the lithium replacements? The Ohmmu website says their battery only weighs 11 pounds.

An Amazon reviewer said the Ohmmu is 16 lbs lighter.

 

[john5520]

I'd also be curious to know what the warranty implication would be going with a lithium battery instead.

 

[Perscitus]

Ohmmu is excellent, installed 18 months ago and never looked back.
Really wakes up the Premium audio, limits parasitic main battery pack drain and works perfect down in real life temps between -20F and up to 110F.

It's a LiFePO4 chemistry battery with proper BMS... not a regular Lithium-ion battery (good for track use in warm climates only).

 

[TLLMRRJ]

I'd also be curious to know what the warranty implication would be going with a lithium battery instead.

You can bet that if you have any issue related to electronics in your car and they see the different battery the SC is going to tell you to put in a factory battery before they will continue working on the car.

 

[Perscitus]

No big deal, pay to play and super easy swap back to stock (plus a chance to trickle charge it, condition and float it while out of the car, say every 6 months).

As usual this is not for everyone, no more than suspension, brake, wheel/tire and even questionable cosmetic mods.

 

[john5520]

You can bet that if you have any issue related to electronics in your car and they see the different battery the SC is going to tell you to put in a factory battery before they will continue working on the car.

Yep. And even if you swap back to the old battery, they could still refuse to repair or replace anything that might have failed, blaming it on the aftermarket battery.

Removing it before going in as Perscitus suggested would probably be OK as long as they can't detect that the battery was removed in the first place.

It is nice to know there are 3rd party options available, but it really is pay-to-play when it's all said and done.

 

[ElectricLove]

Yep. And even if you swap back to the old battery, they could still refuse to repair or replace anything that might have failed, blaming it on the aftermarket battery.

Removing it before going in as Perscitus suggested would probably be OK as long as they can't detect that the battery was removed in the first place.

It is nice to know there are 3rd party options available, but it really is pay-to-play when it's all said and done.

Well, they actually can’t do that and won’t since it violates the Magnusson-Moss Warranty Act. Tesla early on played that game a little in the Roadsters but quickly learned that the reality is they need to support their cars and not try to weasel out of doing so.

Tesla Roadsters were known to have failing “12V distribution” modules which were actually the Tesla interface between the Lotus 12V electronics and the Tesla 12V electronics. They would fail and leave cars totally bricked until replaced (everything relies on 12V to run computers in the car). Tesla went to blame folks who plugged in 12V accessories through their 12V auxiliary power ports (like radars, laptop chargers, etc). But they swiftly backed off that stance once a few owners were made aware of The Magnusson-Moss Act and pushed the issue with them. They replaced any of those components that failed under warranty eventually.

Yes, it is a hassle dealing with “new” companies because of those very thing, they don’t know what they can get away with and don’t have the experience to always be right. This is where the consumers come in, we educate and improve Tesla! It has been happening since day 1!

I know this will seem delusional to new Tesla owners but those of us who have been in this “niche” since before the Model S even existed, back before they built their 1,000th car... we know the journey it took to get here today and that we are all still on this journey together!!!

 

[john5520]

Yeah, the battery dying prematurely and possibly leaving the driver stranded is surely a reason for owners to go aftermarket. It's good to know Tesla had to deal with the MMWA act in the past, so they're familiar with it. I'll look into this some more.

 

[Scrannel]

Of interest...

12 Volt Battery Compendium | TeslaTap

 

[jkdman123]

Of interest...

12 Volt Battery Compendium | TeslaTap

Interesting that they say the Ohmmu is a great replacement for the OEM battery. As weight conscious as Tesla is, I wonder why they didn’t make the Ohmmu standard.

 

[Wennfred]

Replaced my heavy lead acid battery with the Ohmmu Lithium one a year ago, driven in temps as low as 39 degree and as high as 95 degrees with no issues, 12 volt battery is located in the Frunk by the firewall and in the middle. Simply snap loose that cover and you will see it. There is an air vent hoses you need to remove off the battery before pulling it out, it’s heavy so brace yourself.

Fred

 

[Wennfred]

Have there been a lot of 12v failures on the 3? It is an issue on S & X.

There was a batch of 12 volt batteries that went bad in the model 3, also someone just posted in the model Y forum what appears to be a bad 12 volt battery.. still waiting for his results as the service center told him 12 days.

Im going to replace my Lead acid one with the Ohmmu on my model Y as soon as I get it.

Fred

 

[Scrannel]

Perhaps Tesla didn't use the Ohmmu because of the cost.