# Has anyone replaced their 12v battery in their model 3?



## Garlan Garner

Has anyone replaced their 12V battery yet? 

If so...how did you know it needed replacement?


----------



## SoFlaModel3

Garlan Garner said:


> Has anyone replaced their 12V battery yet?
> 
> If so...how did you know it needed replacement?


Both my Model 3 and my wife's died without warning.

After, I Tweeted Elon and got this response....


__ https://twitter.com/i/web/status/1238948776775049216


----------



## StromTrooperM3

Can we update the poll

No
Replaced under warranty Tesla
Replaced with lightweight battery Ohmmu
Replaced with lightweight battery MPP


----------



## StromTrooperM3

Garlan Garner said:


> If so...how did you know it needed replacement?


Does leaving you stranded in the rain count?


----------



## Quicksilver

I am past the two year mark on Quicksilver and was thinking of proactively paying for the 12V battery to be replaced by the service center, rather than waiting to be stranded somewhere. Does it make sense to do this? And how much would the battery service cost?


----------



## Garlan Garner

Quicksilver said:


> I am past the two year mark on Quicksilver and was thinking of proactively paying for the 12V battery to be replaced by the service center, rather than waiting to be stranded somewhere. Does it make sense to do this? And how much would the battery service cost?


Good question. I have no idea.


----------



## StromTrooperM3

Some good tech info on the 12v if anyone is interested. But seriously, no one has considered the aftermarket battery options?

https://teslatap.com/articles/12-volt-battery-compendium/


----------



## StromTrooperM3

SoFlaModel3 said:


> Both my Model 3 and my wife's died without warning


What are the build dates? I've heard they changed 12v vendors... Maybe that's worth noting


----------



## SoFlaModel3

Quicksilver said:


> I am past the two year mark on Quicksilver and was thinking of proactively paying for the 12V battery to be replaced by the service center, rather than waiting to be stranded somewhere. Does it make sense to do this? And how much would the battery service cost?


Both of ours failed at 18 months into ownership so I'm not even sure how to answer...



StromTrooperM3 said:


> Some good tech info on the 12v if anyone is interested. But seriously, no one has considered the aftermarket battery options?
> 
> https://teslatap.com/articles/12-volt-battery-compendium/


I will definitely consider replacing with a better battery aftermarket, but will only do so after the warranty ends.



StromTrooperM3 said:


> What are the build dates? I've heard they changed 12v vendors... Maybe that's worth noting


Mine was a 1/2018 build and my wife a 9/2018 build. If that's true, we both have the "new" battery now hopefully!!


----------



## NR4P

Mine failed 2 mos ago from June 2018 build. 

Doors wouldn't unlock with phone or keycard. But app worked. The TS gave warning messages after I got in to car. But after a few mins car powered up And I drove to service center. Warranty replacement.


----------



## Tony Rigano

Just an observation...looks like Florida members {and a Texas one} had 12V battery issues.....maybe heat related??


----------



## sduck

I already posted my experience to your post on that other forum so won't repeat it here.


----------



## StromTrooperM3

Tony Rigano said:


> Just an observation...looks like Florida members {and a Texas one} had 12V battery issues.....maybe heat related??


From the site I quoted above.

Why Lithium-Ion 12v Battery is a Bad Idea
There are 12v lithium-ion drop-in replacements for ICE car batteries. These are quite a bit more expensive but do weigh less - so you'd think they would be great in an EV. Not so fast. Turns out for Tesla's application the frequent deep charge/discharge cycles would greatly shorten the life of a lithium-ion battery designed for ICE cars, perhaps only lasting 6 months to a year. *Since there is no climate control on the 12v battery, it's life would also be shortened if you encounter climate extremes.* Lithium-ion 12v battery makes little economic sense in a Tesla.


----------



## JasonF

I'm in Florida, and I haven't had my 12V battery die yet. It's kept in a garage, though I don't see how that would make a difference since the garage is not climate controlled (it's about 90+ in there in the summer).

I suppose the best way to test an automotive 12V battery would be check it once every few months with a voltmeter. Voltages below 12 can cause damage to those batteries over time (and/or indicate damage that occurred already) so if you get below 12 volts, re-check it periodically over the next 24 hours and see if the car decided to top it off. If it's still stuck at 11 volts, start planning for replacement.

One of those battery chargers/maintainers could also tell you if attempted charging fails, but I don't yet know if it's safe to hook one of those up while the battery is still connected to the car. I would _guess_ not, because the DC-DC converter might not like 16 volts and 8 amps coming back at it, and it's probably an expensive part to replace. I also don't know the effect of disconnecting the 12V battery from the car for the time it takes to charge/maintain it, but that seems far less risky to test.


----------



## Garlan Garner

Has anyone actually purchased a 3rd party battery?

How is it working out for you?


----------



## Garlan Garner

SoFlaModel3 said:


> Both my Model 3 and my wife's died without warning.
> 
> After, I Tweeted Elon and got this response....
> 
> 
> __ https://twitter.com/i/web/status/1238948776775049216


I wonder if a 3rd party battery would register/work properly with Elons proposed future 12v battery monitor.


----------



## Garlan Garner

JasonF said:


> I'm in Florida, and I haven't had my 12V battery die yet. It's kept in a garage, though I don't see how that would make a difference since the garage is not climate controlled (it's about 90+ in there in the summer).
> 
> I suppose the best way to test an automotive 12V battery would be check it once every few months with a voltmeter. Voltages below 12 can cause damage to those batteries over time (and/or indicate damage that occurred already) so if you get below 12 volts, re-check it periodically over the next 24 hours and see if the car decided to top it off. If it's still stuck at 11 volts, start planning for replacement.
> 
> One of those battery chargers/maintainers could also tell you if attempted charging fails, but I don't yet know if it's safe to hook one of those up while the battery is still connected to the car. I would _guess_ not, because the DC-DC converter might not like 16 volts and 8 amps coming back at it, and it's probably an expensive part to replace. I also don't know the effect of disconnecting the 12V battery from the car for the time it takes to charge/maintain it, but that seems far less risky to test.


I have "Scan My Tesla" installed. It provides a live voltage display of the 12v battery.

However what I don't know is what voltage is considered bad or good in a Tesla. I mean, if the big battery pack is keeping the 12V battery at a constant 13v....then is a 12.5 constant voltage a bad thing? or is 14v a bad thing?


----------



## JasonF

Garlan Garner said:


> However what I don't know is what voltage is considered bad or good in a Tesla. I mean, if the big battery pack is keeping the 12V battery at a constant 13v....then is a 12.5 constant voltage a bad thing? or is 14v a bad thing?


The name "12 volt battery" is actually a misnomer. From what I know about them, any voltage above 12.0 and below 15.0 volts is considered normal (usually they end up averaging 13.9 to 14.2 when full). You can overcharge a 12V battery as high as 16 volts, but it won't be happy and will start outgassing. Anything below 12 volts is considered weak or damaged, and the battery is considered dead somewhere around 9 volts. The imprecision in this paragraph is because the limits vary a bit between brands and types.

One thing I forgot to mention: If the Tesla is currently charging the battery, you might see a voltage as high as 16 volts - that's coming from the DC-DC converter. It's best if you measure the battery when you know the car is asleep and the contactors are open.


----------



## StromTrooperM3

SoFlaModel3 said:


> I will definitely consider replacing with a better battery aftermarket, but will only do so after the warranty ends


After the continuous reports of failures and needs of warranty of non EV specific parts I'll be skipping any warranty parts that have an aftermarket option


----------



## Tony Rigano

I have a 2013 RAV electric vehicle as well as my M3 and a year ago the 12 V battery baked on me. Without researching I purchased a regular ICE type battery not knowing that a ‘deep cell’ marine type battery would have been a better option. From the information garnered from different sources it appears the Tesla battery has a ‘deep cell’ type battery. Could the Marine type deep cell work in our cars?


----------



## NR4P

Tony Rigano said:


> Just an observation...looks like Florida members {and a Texas one} had 12V battery issues.....maybe heat related??


I have lived in Florida for more than 40 years. Any car I ever owned had batteries fail in well under 5 years. In fact my last ICE car battery failed in 20 months. It had a 24 mos full replacement so I got a new battery at N/C. Then a few months later the M3.

The Tesla battery is not unique in failing prematurely. Yes it's the heat. Battery OEMs won't argue this.


----------



## jim0266

Garlan Garner said:


> I have "Scan My Tesla" installed. It provides a live voltage display of the 12v battery.
> 
> However what I don't know is what voltage is considered bad or good in a Tesla. I mean, if the big battery pack is keeping the 12V battery at a constant 13v....then is a 12.5 constant voltage a bad thing? or is 14v a bad thing?


I too run SMT and have the same question. I see my 12V mostly at 15V with all the screenshots I've saved out of SMT. I was surprised to see the 12V above 14V.


----------



## NR4P

I am able to monitor battery voltage anytime I am in the vehicle from the 12v line in console. When I first get in and car powers on, it will be normally be between 13.7 and 14.2V. During drives, it will be as high as 14.5v and low as 13.2. Before my battery failed, I noticed 14.7v-14.9v during drives. I suspected it was overcharging due to impending failure but had no problems. And sure enough, about 2 weeks later, it failed. 

When it failed, I got various TS messages and the voltage monitor showed 9V and then crept back to 12.x (don't recall exactly) and I drove it to the service center.

Next time I see the voltage get that high again, I know I need to test it. As Jeff Foxworthy says "here's your sign".


----------



## Garlan Garner

NR4P said:


> I am able to monitor battery voltage anytime I am in the vehicle from the 12v line in console. When I first get in and car powers on, it will be normally be between 13.7 and 14.2V. During drives, it will be as high as 14.5v and low as 13.2. Before my battery failed, I noticed 14.7v-14.9v during drives. I suspected it was overcharging due to impending failure but had no problems. And sure enough, about 2 weeks later, it failed.
> 
> When it failed, I got various TS messages and the voltage monitor showed 9V and then crept back to 12.x (don't recall exactly) and I drove it to the service center.
> 
> Next time I see the voltage get that high again, I know I need to test it. As Jeff Foxworthy says "here's your sign".


That's good to know.

I was actually thinking the opposite of what you posted. I would have thought that a higher voltage would have been a "better" thing. From your post I might have to change my thinking in that a higher voltage would eventually cause a lower voltage to happen.

Hmmmmm......very interesting. I'll have to watch for a high voltage.

This leads me to my next question. Do you think that the 3rd party lithium batteries would fail in the same fashion? The reason for the question is: If Tesla inserts the 12v battery monitor function in the car....will it properly react to a 3rd party battery.....OR will it only react to the OEM type battery? hmmmm


----------



## iChris93

NR4P said:


> Before my battery failed, I noticed 14.7v-14.9v during drives. I suspected it was overcharging due to impending failure but had no problems. And sure enough, about 2 weeks later, it failed.


That is an interesting observation. I hope Tesla is tracking this so that they find the true trend and can give a warning when our batteries are starting to exhibit the beginning of the trend.


----------



## Jim H

iChris93 said:


> That is an interesting observation. I hope Tesla is tracking this so that they find the true trend and can give a warning when our batteries are starting to exhibit the beginning of the trend.


The high charge rate has been reported since the M3 first came out in 2018. I reported a 14.98v charge in 11/18, when some battery failures were being reported. I felt the high charge rate were overcharging the batteries and the cause for the failures. My battery is still ok, but I am still concerned that the high charge rate will lead to premature battery failure.


----------



## NickJonesS71

Garlan Garner said:


> If Tesla inserts the 12v battery monitor function in the car....will it properly react to a 3rd party battery.....OR will it only react to the OEM type battery?


A battery only has a positive and negative terminal. The Tesla software would simply read the voltage ranges. I see no reason why the 3rd party battery would react any differently.

The 3rd party batteries are of a different chemistry, they claim These batteries handle a wide temperature range, support deep discharges, and many more charging cycles than the stock AGM battery


----------



## Garlan Garner

NickJonesS71 said:


> A battery only has a positive and negative terminal. The Tesla software would simply read the voltage ranges. I see no reason why the 3rd party battery would react any differently.
> 
> The 3rd party batteries are of a different chemistry, they claim These batteries handle a wide temperature range, support deep discharges, and many more charging cycles than the stock AGM battery


There is a third party Li3 12.8V battery. It has a battery management system on the inside that keeps each 18650 cell charged and shuts off to never over charge. So...a Li3 battery is essentially 12.8v at all times. Never 14v or 15v.

Li3 battery cells are designed for maximum output current and voltage until the very end of their charge cycle. They don't tail off on their voltage like Lead Acid batteries.










There are many many differences between a 3rd party 12.8v Li3 and a 12v regular battery that comes with our Tesla's. If Tesla's new monitoring software watches for 15v to know that their battery is going bad.....it would NEVER see it with a 3rd party Li3 battery.

Lastly, you don't need a deep discharge 12v battery as the main pack keeps the battery charged at all times. Since there is no starter to start an engine....you don't need to draw tremendous amounts of current from it either.


----------



## Garlan Garner

I wish for the 12V battery success of this guy.

_"Even things like the 12-volt battery, which has been a problem with Tesla vehicles in the past, have performed decently well on this Model X. It had to be replaced three times over the lifetime of the car, which is nothing to worry about at 400,000 miles."_

https://electrek.co/2020/05/11/tesla-model-x-extreme-mileage-repair-maintenance/

Scroll down and check out his chart concerning his 12v battery and various other repairs.


----------



## littlD

Garlan Garner said:


> Good question. I have no idea.


Replaced Middie's 12V along with the 2 year maintenance because of @SoFlaModel3 experience.

Cost when done at Tesla Service Center in Chesterfield MO (Details copied from receipt):

Concern: Customer states: replace 12v battery
Verified concern. Removed and replaced 12 v battery. Vehicle is operating as designed.
Correction: Battery - 12V (Remove & Replace) Price
35.00
Adjustment
0.00
Subtotal
35.00
Parts Replaced or Added
Part Quantity Unit
Price
Price Adjustment Subtotal
ASY,12V BATT AND VENT PLUG,M3(1129182-00-B) 1.0 85.00 85.00 0.00 85.00
Parts Subtotal 85.00
*Pay Type: Customer Pay 120.00*
_*Total Parts Amount 85.00
Total Labor Amount 35.00*_


----------



## Quicksilver

littlD said:


> Replaced Middie's 12V along with the 2 year maintenance because of @SoFlaModel3 experience.
> 
> Cost when done at Tesla Service Center in Chesterfield MO (Details copied from receipt):
> 
> Concern: Customer states: replace 12v battery
> Verified concern. Removed and replaced 12 v battery. Vehicle is operating as designed.
> Correction: Battery - 12V (Remove & Replace) Price
> 35.00
> Adjustment
> 0.00
> Subtotal
> 35.00
> Parts Replaced or Added
> Part Quantity Unit
> Price
> Price Adjustment Subtotal
> ASY,12V BATT AND VENT PLUG,M3(1129182-00-B) 1.0 85.00 85.00 0.00 85.00
> Parts Subtotal 85.00
> *Pay Type: Customer Pay 120.00*
> _*Total Parts Amount 85.00
> Total Labor Amount 35.00*_


Thanks @littlD, that looks to be a reasonable price for that 12V battery replacement.


----------



## NickJonesS71

Garlan Garner said:


> If Tesla's new monitoring software watches for 15v to know that their battery is going bad.....it would NEVER see it with a 3rd party Li3 battery.


Good to know!

What are they using now as a monitoring range?


----------



## Garlan Garner

NickJonesS71 said:


> Good to know!
> 
> What are they using now as a monitoring range?
> 
> View attachment 33955


The feature isn't out yet.

There has only been a promise of a future feature so far.


----------



## SoFlaModel3

Garlan Garner said:


> The feature isn't out yet.
> 
> There has only been a promise of a future feature so far.


That feature has been there for a while, but the problem for many of us is that we never saw the message and the battery died. My ask was for monitoring so the health could be tracked and more advanced notices provided.


----------



## NR4P

Car OEMs have been dealing with this issue for decades. Batteries must be under load to be tested, reliably.
From autobatteries.com

*When Fully Charged, How Many Volts Should A Car Battery Have?*
Fully charged automotive batteries should measure at 12.6 volts or above. When the engine is running, this measurement should be 13.7 to 14.7 volts. If you don't have a multimeter to tell you the voltage of your battery, you can do a test of your electrical system by starting the car and turning on the headlights. If they are dim, that indicates the lights are running off the battery and that little or no charge is being produced by the alternator. If the lights get brighter as you rev the engine, it means the alternator is producing some current, but may not be producing enough at idle to keep the battery properly charged. If the lights have normal brightness and don't change intensity as the engine is revved, your charging system is probably functioning normally. If you've been experiencing problems with your battery system and the headlight test checks out okay, you should check whether or not the battery is holding a charge, or if something on the vehicle is discharging it.

*How Do You Perform A Load Test?*
To pass a load test, the battery must maintain 9.6 volts at 15 seconds when tested at one-half the CCA rating and 70°F (or above). This test must be done with a true load (carbon pile) and not one of the hand-held testers that work off a conductance algorithm. The test must be run with the battery in a high state of charge. Be sure to read and follow all safety and handling instructions on the battery, this website and your battery tester. If you would like your battery tested, use our Find a Retailer for a location near you.


----------



## Garlan Garner

SoFlaModel3 said:


> That feature has been there for a while, but the problem for many of us is that we never saw the message and the battery died. My ask was for monitoring so the health could be tracked and more advanced notices provided.


Indeed. The monitoring feature for showing us the monitoring isn't out yet.

Its kinda like when I cant tell the status of the battery in my garage door opener. I have no clue how good it is until it periodically stops working from time to time. I'm not monitoring it....I can just tell when its dying.

I may be wrong but it appears that the car can tell when the 12v is about dead, but I'm not sure it's monitoring/tracking.

Who knows?


----------



## Fabfours

Yes on my last service in November after nearly 4 years ownership.


----------



## Tony Rigano

Has anyone put a deep cell battery in their Tesla.?


----------



## Needsdecaf

So what's the consensus on 12v? Seems like service gives people the runaround / long wait times when they get messages, and often people end up with dead cars. I'm not above replacing the 12v. out of my pocket and asking Tesla for a reimbursement. I'd much rather do that than get stranded. 

Is it that easy?


----------



## GDN

I voted above and added my own story in my own thread, but the short of it is I had the 12v replaced on the RWD older car back in December. The car is 30 months old. The car issued the standard messages, I opened a service ticket and after review they moved the appointment up and 3 days later I had the 12 v battery replaced under warranty.

I expected nothing less, or at least a prorated cost. I believe Tesla is going above and beyond by not prorating the cost of the battery, but that is between them and their supplier. I expect a battery to last 3 years and then prorated until 5 likely.


----------



## Firewired

Both my wife and I have Model 3s which we took delivery of 09/18. Both had batteries 12 V batteries go dead at the 24 month mark.


----------



## StPeteBeach

Our 25 month old, 24,000 mile Model 3 12v battery failed unexpectedly with multiple warnings. Stranded my wife at an airport parking garage. Tesla dispatched roadside assistance and they replaced the battery at no charge. Roadside guy told my wife that the 12v batteries are only good for about 2 years in Florida. 

Multiple warnings/alerts that all appeared simultaneously on attached pic.


----------



## Johnm6875

In the recent interview with Sandy Munro, Elon Musk stated an Li-ion battery would replace the Pb battery in the MS. And, this new battery would would have a life-time approximately the same as the car's pack. Apparently, the concerns over this type of battery have been addressed. It'll be interesting to find out the particulars and if using a similar, or the same, could be an OEM M3 replacement. I'd pay extra to have a "no worry" alternative in my 2018.


----------



## GDN

Johnm6875 said:


> In the recent interview with Sandy Munro, Elon Musk stated an Li-ion battery would replace the Pb battery in the MS. And, this new battery would would have a life-time approximately the same as the car's pack. Apparently, the concerns over this type of battery have been addressed. It'll be interesting to find out the particulars and if using a similar, or the same, could be an OEM M3 replacement. I'd pay extra to have a "no worry" alternative in my 2018.


We just had to have a 12 v replaced in December. I would have paid extra to upgrade too. I know several are on the market and have been put in the 3, but I don't know if they have different charging requirements. Do they charge less frequently, slower, faster? Not sure how they work just swapping 1:1 vs the systems being designed for that battery.


----------



## Needsdecaf

GDN said:


> We just had to have a 12 v replaced in December. I would have paid extra to upgrade too. I know several are on the market and have been put in the 3, but I don't know if they have different charging requirements. Do they charge less frequently, slower, faster? Not sure how they work just swapping 1:1 vs the systems being designed for that battery.


Antigravity makes some pretty good aftermarket LiIon 12v batteries for a variety of automotive and other applications. Here's their FAQ page. Some decent info here.

https://antigravitybatteries.com/help-center/faq/lithium-starter-batteries/#general-batt-faq


----------



## M3OC Rules

Needsdecaf said:


> Antigravity makes some pretty good aftermarket LiIon 12v batteries for a variety of automotive and other applications. Here's their FAQ page. Some decent info here.
> 
> https://antigravitybatteries.com/help-center/faq/lithium-starter-batteries/#general-batt-faq


Interesting. I was poking around and noticed they do not give any temperature ranges. I found a forum post here from someone who claims to have talked to them. They say the temperature of the LiFePO4 goes down to 0 degrees F and they are working on another one that goes down to -22 deg F. I didn't look thoroughly but I don't see the new one. Doesn't sound good for cold climates. I wonder how Tesla is handling this. It makes me think the likelihood of a retrofit is pretty small and that they somehow heat the 12v battery if necessary.


----------



## android04

M3OC Rules said:


> Interesting. I was poking around and noticed they do not give any temperature ranges. I found a forum post here from someone who claims to have talked to them. They say the temperature of the LiFePO4 goes down to 0 degrees F and they are working on another one that goes down to -22 deg F. I didn't look thoroughly but I don't see the new one. Doesn't sound good for cold climates. I wonder how Tesla is handling this. It makes me think the likelihood of a retrofit is pretty small and that they somehow heat the 12v battery if necessary.


As far as how Tesla will handle cold temps with their 12v battery, they could possibly have a resistive heater built-in to the battery. Or maybe just a heating pad or cover around the battery. It could be turned on when certain conditions are met.


----------



## Madmolecule

My car went nuts when the battery died. It was very dangerous to drive. Good news is Tesla picked up the car, gave me a uber credit and no charge for the new battery. I did not know it would be covered by warranty with around 40K miles and 24 months.


----------



## MachV

My 2018 Model 3 12v died after 23 months and 16,000 miles. My cars VIN is 099xxx. It did nothing other than indicate the warning message on the touchscreen.
I got it replaced the next day for free at the closest Tesla service center. Took them about 1.5-2hrs. 
I didn't want to wait for it to strand me so I got it solved ASAP.


----------



## Johnm6875

Using the Antigravity battery finder, they suggest the following: Group-51R Car Battery $659.99 – $749.99

Now I need to decide cost verses convenience. Their battery also has a number of functions I would doubtfully use (wireless keyfob remote, self-restarting capabilities, higher voltage at start-up). They do tout triple the lifetime of lead-acid, but more than triple the cost is a lot of "friction" in the decision.


----------



## littlD

Johnm6875 said:


> Using the Antigravity battery finder, they suggest the following: Group-51R Car Battery $659.99 - $749.99
> 
> Now I need to decide cost verses convenience. Their battery also has a number of functions I would doubtfully use (wireless keyfob remote, self-restarting capabilities, higher voltage at start-up). They do tout triple the lifetime of lead-acid, but more than triple the cost is a lot of "friction" in the decision.


Maybe I'm missing something. I just replace my 12V every 2 years. Cost me $120 for the battery and labor at the Service Center.

Seems a cheaper option.


----------



## JasonF

littlD said:


> Maybe I'm missing something. I just replace my 12V every 2 years. Cost me $120 for the battery and labor at the Service Center.
> 
> Seems a cheaper option.


I'm not really sold on a $750 lithium battery either. Maybe if it came with a lifetime warranty, and they would replace it for free as long as you own the car - otherwise, you're taking the same risk as with a $120 AGM/lead acid battery. It might also only last 2 years, especially if you live somewhere very hot or very cold.


----------



## Needsdecaf

JasonF said:


> I'm not really sold on a $750 lithium battery either. Maybe if it came with a lifetime warranty, and they would replace it for free as long as you own the car - otherwise, you're taking the same risk as with a $120 AGM/lead acid battery. It might also only last 2 years, especially if you live somewhere very hot or very cold.


The antigravity battery is extremely light. That's it's main purpose. If you don't need the weight savings, it's pretty much a waste of money otherwise.


----------



## rrolsbe

Madmolecule said:


> My car went nuts when the battery died. It was very dangerous to drive. Good news is Tesla picked up the car, gave me a uber credit and no charge for the new battery. I did not know it would be covered by warranty with around 40K miles and 24 months.


I could understand going nuts before the HV contactors close but if the DC-to-DC converter is working properly and supplying a good 13+Volts why would driving be dangerous. You might get an error message(s) relating to the failing 12V battery. If for some reason the failing 12V battery causes the DC-to-DC converter to not deliver 13+V to the 12V bus, that could cause strangeness while driving. I have disconnected my negative cable from the neg 12V post, after the car exits the sleep state, and the car fully functioned and was drive-able (except for an center screen error that the 12V battery was disconnected).


----------



## JasonF

rrolsbe said:


> I could understand going nuts before the HV contactors close but if the DC-to-DC converter is working properly and supplying a good 13+Volts why would driving be dangerous. You might get an error message(s) relating to the failing 12V battery. If for some reason the failing 12V battery causes the DC-to-DC converter to not deliver 13+V to the 12V bus, that could cause strangeness while driving. I have disconnected my negative cable from the neg 12V post, after the car exits the sleep state, and the car fully functioned and was drive-able (except for an center screen error that the 12V battery was disconnected).


If a 12V battery is sufficiently shorted internally, it can cause the entire 12V bus to die occasionally, and the DC-DC converter would shut off to protect itself. It's very rare, but it can happen.

I experienced it in a gas car years ago. I jumped the battery to get the car started, but the battery had such a strong internal short that turning on the headlights, radio, wipers, or even turn signals would stall the engine. I barely made it to a repair place in dark clouds and heavy rain without using any accessories.


----------



## Madmolecule

Oh it went nuts, I first got and emergeny brake alarm, then the brakes started acting crazy then I could barley steer it. Luckily it was all in my neighborhood. I thought I was close to bricking it. I was amazed that with a new battery and a software reload it was back to normal.


----------



## TrevP

No issues on my car so far (2019) but if you get 12V messages don't fool around, call Tesla immediately. Any failure of the 12V will leave you stranded


----------



## tencate

> Group-51R Car Battery

Can someone clarify, I thought it was a Group 51 (or perhaps reversed + and - don't really matter?) Duracell makes a Group 51 that is a pretty good match to the Atlas specs. That's likely what I'm going to go with when mine finally dies. My Service Center is 5.5 hours away :-(


----------



## iChris93

tencate said:


> My Service Center is 5.5 hours away :-(


Mobile should be able to do this.


----------



## FRC

tencate said:


> > Group-51R Car Battery
> 
> Can someone clarify, I thought it was a Group 51 (or perhaps reversed + and - don't really matter?) Duracell makes a Group 51 that is a pretty good match to the Atlas specs. That's likely what I'm going to go with when mine finally dies. My Service Center is 5.5 hours away :-(


Can anyone weigh in who has replaced their 12v with a third party supplier? What was your experience and exactly what battery did you go to?


----------



## Needsdecaf

JasonF said:


> If a 12V battery is sufficiently shorted internally, it can cause the entire 12V bus to die occasionally, and the DC-DC converter would shut off to protect itself. It's very rare, but it can happen.
> 
> I experienced it in a gas car years ago. I jumped the battery to get the car started, but the battery had such a strong internal short that turning on the headlights, radio, wipers, or even turn signals would stall the engine. I barely made it to a repair place in dark clouds and heavy rain without using any accessories.


I had that exact same thing happen to me. AC went, then lights, then power started dropping. Was driving on the highway lights off to try to make it to an exit.


----------



## JasonF

Needsdecaf said:


> I had that exact same thing happen to me. AC went, then lights, then power started dropping. Was driving on the highway lights off to try to make it to an exit.


Because it has a DC-DC converter, you might have been better off to turn the A/C all the way up to keep the contactors closed, and then disconnect the 12V battery entirely. I don't know for certain if that would work, but it seems like it should.


----------



## Needsdecaf

JasonF said:


> Because it has a DC-DC converter, you might have been better off to turn the A/C all the way up to keep the contactors closed, and then disconnect the 12V battery entirely. I don't know for certain if that would work, but it seems like it should.


Sorry, was replying to what you said about years ago. Was years ago for me too in an ICE car.


----------



## JasonF

Needsdecaf said:


> Sorry, was replying to what you said about years ago. Was years ago for me too in an ICE car.


Whoops! Well it's still a thing you definitely can't do with an ICE car - they won't run with the 12V battery disconnected.


----------



## android04

tencate said:


> > Group-51R Car Battery
> 
> Can someone clarify, I thought it was a Group 51 (or perhaps reversed + and - don't really matter?) Duracell makes a Group 51 that is a pretty good match to the Atlas specs. That's likely what I'm going to go with when mine finally dies. My Service Center is 5.5 hours away :-(


The "R" designation means that the + and - posts are flipped on the battery. A non-R battery will work if the battery cables are long enough to reach the posts a few inches away. I've read somewhere that a guy bought a Group See 51 battery (non-R) and it worked on his Model 3 because the cables were long enough for the offset.


----------



## JWardell

rrolsbe said:


> I could understand going nuts before the HV contactors close but if the DC-to-DC converter is working properly and supplying a good 13+Volts why would driving be dangerous. You might get an error message(s) relating to the failing 12V battery. If for some reason the failing 12V battery causes the DC-to-DC converter to not deliver 13+V to the 12V bus, that could cause strangeness while driving. I have disconnected my negative cable from the neg 12V post, after the car exits the sleep state, and the car fully functioned and was drive-able (except for an center screen error that the 12V battery was disconnected).


That works until you park the car. The contactors are precharged by the 12v system. So if you don't have a good 12v from your battery, then you can't get high voltage to generate more 12v.
If you keep a USB 12v jumpstarter battery in your car, it will very likely keep you from being stranded in this situation


----------



## JasonF

JWardell said:


> That works until you park the car. The contactors are precharged by the 12v system. So if you don't have a good 12v from your battery, then you can't get high voltage to generate more 12v.
> If you keep a USB 12v jumpstarter battery in your car, it will very likely keep you from being stranded in this situation


When my 12V battery died, I actually left Climate Keeper running and made two stops before going to the Service Center - and left Climate Keeper on at the Service Center as well, until they brought it inside. I wasn't sure if it was making a difference at first, until they told me the mechanic got out and shut the car door just after driving it into the bay, and then had to replace the 12V battery near the shop door because the car didn't want to move again.

What was interesting about it was that I thought after sitting so long, and with incoming rain dropping the outside temperature, the compressor probably would have cycled off and opened the contactors. Apparently as long as Climate Keeper is running, the contactors stay closed. Or maybe that's what sucked the last of the 12V battery dry, but then why would it have waited until the car was moved?


----------



## JWardell

JasonF said:


> When my 12V battery died, I actually left Climate Keeper running and made two stops before going to the Service Center - and left Climate Keeper on at the Service Center as well, until they brought it inside. I wasn't sure if it was making a difference at first, until they told me the mechanic got out and shut the car door just after driving it into the bay, and then had to replace the 12V battery near the shop door because the car didn't want to move again.
> 
> What was interesting about it was that I thought after sitting so long, and with incoming rain dropping the outside temperature, the compressor probably would have cycled off and opened the contactors. Apparently as long as Climate Keeper is running, the contactors stay closed. Or maybe that's what sucked the last of the 12V battery dry, but then why would it have waited until the car was moved?


The cabin temp is monitored while the car is asleep (assuming you don't have sentry mode on), but when it hits 120 and triggers a cool down, it will wake up, enable HV, and then fire up the compressor or fans. You can see that happening if you look at your parking logs on hot days in teslafi. It will then go back to sleep after ~10min, or never if it heats up again too fast
As for service, they probably left the car long enough for it to go to sleep.


----------



## JasonF

JWardell said:


> As for service, they probably left the car long enough for it to go to sleep.


They absolutely did - since I was basically a last minute appointment, I was there for about an hour and a half. The car was outside for about 45 minutes, and then brought into the service bay.

The part that was educational for me though was that while the car was sitting outside for 45 minutes with Climate Keeper on, it didn't open the contactors even while just the fan was running (because the temperature outside was dropping during the rainstorm). From what you're saying, I guess it only does that if there are more than 10-ish minutes between compressor cycles? Or does it just keep them closed as long as Climate Keeper is on, so it doesn't have to repeatedly open and close them while cycling the compressor?


----------



## iChris93

JasonF said:


> They absolutely did - since I was basically a last minute appointment, I was there for about an hour and a half. The car was outside for about 45 minutes, and then brought into the service bay.
> 
> The part that was educational for me though was that while the car was sitting outside for 45 minutes with Climate Keeper on, it didn't open the contactors even while just the fan was running (because the temperature outside was dropping during the rainstorm). From what you're saying, I guess it only does that if there are more than 10-ish minutes between compressor cycles? Or does it just keep them closed as long as Climate Keeper is on, so it doesn't have to repeatedly open and close them while cycling the compressor?


I think there is a misunderstanding between you and @JWardell. I think @JWardell is thinking about cabin overhear protection and you're talking about leaving climate on to whatever your set temperate is.


----------



## JasonF

iChris93 said:


> I think there is a misunderstand between you and @JWardell. I think @JWardell is thinking about cabin overhear protection and you're talking about leaving climate on to whatever your set temperate is.


That's why I clarified it.  That's what happens sometimes when posting at 1:22 am!


----------



## davidviolin

I replaced the 12v battery myself with the Li-on Mountain pass performance one. A little bit tricky if you have an AWD car, but a great side effect is the sound system now sounds alot better! It was always good, but now its really fantastic on par with my bowers and Wilkins system in my BMW 8.
If you are going to replace the 12v battery I would recommend spending the extra on the Li-on. Besides not having to worry about replacement for 8-10 years it also saved me 20lb of weight.


----------



## garsh

davidviolin said:


> ... a great side effect is *the sound system now sounds alot better!*


----------



## sduck

There's been quite a lot of discussion about this claim of better audio system sound with the Li-on batteries on another forum. From what I can gather there's no real technical reason this should happen, but a lot of the Li-on users swear it's true. It seems like a pretty subjective thing that would be pretty hard to test for objectively, and the odds of confirmation bias skewing the results are pretty good.


----------



## JasonF

sduck said:


> There's been quite a lot of discussion about this claim of better audio system sound with the Li-on batteries on another forum. From what I can gather there's no real technical reason this should happen, but a lot of the Li-on users swear it's true. It seems like a pretty subjective thing that would be pretty hard to test for objectively, and the odds of confirmation bias skewing the results are pretty good.


Theoretically a lithiuim 12V battery would be able to produce more peak amps on demand, which would allow the subwoofer to drive harder. There are a couple of problems with that theory though: First, that the amp is probably current limited so it doesn't fry the entire electrical system if you turn the audio system up too loud. Second is the DC-DC converter, if it's not current limited, can out-amp any 12V battery because it has the full power of the main battery behind it.


----------



## iChris93

JasonF said:


> Second is the DC-DC converter, if it's not current limited, can out-amp any 12V battery because it has the full power of the main battery behind it.


I don't think this is necessarily true. The current limit of the DC-DC converter could be 200 A while batteries are excellent current sources and could source over 2x that.


----------



## JasonF

iChris93 said:


> I don't think this is necessarily true. The current limit of the DC-DC converter could be 200 A while batteries are excellent current sources and could source over 2x that.


That's why I added "if it's not current limited". It might be.

Either way it wouldn't matter, since the amp is likely current limited so it doesn't set fire to the electrical system.


----------



## rrolsbe

JWardell said:


> The cabin temp is monitored while the car is asleep (assuming you don't have sentry mode on), but when it hits 120 and triggers a cool down, it will wake up, enable HV, and then fire up the compressor or fans. You can see that happening if you look at your parking logs on hot days in teslafi. It will then go back to sleep after ~10min, or never if it heats up again too fast
> As for service, they probably left the car long enough for it to go to sleep.


I have not used COP cabin overheat protection. I thought if COP is enabled the car would never enter sleep state? If COP is NOT enabled, are you saying the car will wake from sleep state to cool the cabin ,if temp reaches 120F then reenter sleep state?


----------



## JWardell

rrolsbe said:


> I have not used COP cabin overheat protection. I thought if COP is enabled the car would never enter sleep state? If COP is NOT enabled, are you saying the car will wake from sleep state to cool the cabin ,if temp reaches 120F then reenter sleep state?


If you turn on preconditioning to actively cool or heat the car, then it will stay awake, although I believe there is a time limit.
If you turn on cabin overheat protection, then the car will sleep as normal, but wake up when the cabin temp reaches 120F, turn on fans (or AC if you have that set) and turn back off when it falls below [100 I think]


----------



## GeoJohn23

Late Sept 2018 delivery Model 3, Northern California car, currently on software version 2021.4.11, this message popped up on Friday - made an appointment via the phone app for mobile service Thursday (they actually messaged me on Monday Noon that they had a mobile service opening that day from 1-4 if I wanted it, but my wife had just left with the car shortly before for the afternoon, so I just stayed with the Thurs appointment).

<edit> can't seem to figure out how to attach a photo vis the phone, just says it's too large (older forum software had options for size of photo attachments; but don't see that now). Anyway, message was longish saying that the 12V battery has degraded and should be replaced soon, although it should continue to work for a while; but software updates will be suspended until the battery is replaced. It then gave some info about what to do if the battery does go dead...


----------



## Garlan Garner

StromTrooperM3 said:


> From the site I quoted above.
> 
> Why Lithium-Ion 12v Battery is a Bad Idea
> There are 12v lithium-ion drop-in replacements for ICE car batteries. These are quite a bit more expensive but do weigh less - so you'd think they would be great in an EV. Not so fast. Turns out for Tesla's application the frequent deep charge/discharge cycles would greatly shorten the life of a lithium-ion battery designed for ICE cars, perhaps only lasting 6 months to a year. *Since there is no climate control on the 12v battery, it's life would also be shortened if you encounter climate extremes.* Lithium-ion 12v battery makes little economic sense in a Tesla.


Good thing mine came with a 4 year warranty.


----------



## GeoJohn23

GeoJohn23 said:


> Late Sept 2018 delivery Model 3, Northern California car, currently on software version 2021.4.11, this message popped up on Friday - made an appointment via the phone app for mobile service Thursday (they actually messaged me on Monday Noon that they had a mobile service opening that day from 1-4 if I wanted it, but my wife had just left with the car shortly before for the afternoon, so I just stayed with the Thurs appointment).
> 
> <edit> can't seem to figure out how to attach a photo vis the phone, just says it's too large (older forum software had options for size of photo attachments; but don't see that now). Anyway, message was longish saying that the 12V battery has degraded and should be replaced soon, although it should continue to work for a while; but software updates will be suspended until the battery is replaced. It then gave some info about what to do if the battery does go dead...


12V battery replaced today by Mobile Service in less than 7 minutes (half of which was the time to check/adjust tire pressure as required by CA law anytime they do any service). Fully covered under warranty, no charge.


----------



## hkluis

Mine has just been replaced after only 3 years (of which one year had almost no-operation due to the pandemic lockdown) and 35K miles. But I was pleasantly surprised that it's still covered under warranty. The mobile service came an hour early, and but the time I was notified of his presence, he was already done. He said the early batteries did have some longevity problems, but the replacement should last over 5 years. Tesla is a breakthrough not just in technology but how they treat customers!


----------



## ULEWZ

Mine lasted just 4 months shy of 3 years. Always left on the charger and always garaged. It gave my wife quite the scare when the drivers window went half way down, the screen was black, and she could not open the doors. She called me on her cell from the garage and I had to go out to show her how to open the door manually (yes, I showed her before). Smelled a little rotten eggs from the fronk area, and when the service advisor removed the existing battery, the sides were bulging. NO cost to replace by the way, but the batteries looked identical.


----------



## JasonF

ULEWZ said:


> Smelled a little rotten eggs from the fronk area, and when the service advisor removed the existing battery, the sides were bulging. NO cost to replace by the way, but the batteries looked identical.


Somewhat ironically, the rotten egg smell and bulging can be caused by overcharging.


----------



## ULEWZ

JasonF said:


> Somewhat ironically, the rotten egg smell and bulging can be caused by overcharging.


And this: 

*1. Rotten egg smell*
One of the first symptoms of a problem with the battery is a rotten egg smell. Conventional acid lead automotive batteries are filled with a mixture of water and sulfuric acid. As the battery wears, some of the acid and water may evaporate which will disturb the mixture. This may cause the battery to overheat or boil, which will produce an unpleasant smell, and even smoking in more severe cases.


----------



## Jim H

Garlan Garner said:


> Good thing mine came with a 4 year warranty.


If your Lithium replacement fails within the 4 year warranty period, you get a free replacement. Good deal unless it fails in middle of no where on a trip. Can't call Tesla to replace non OEM battery under warranty. Get a tow and wait till free replacement Lithium gets sent to you. When Lithiums go, they seem to go abruptly, not a gradual decrease in output. Not sure if Lithiums can be jumped started either. 
just a few things to consider with going Lithium 12v. I was going to go this route as well, until my 12v failed and was replaced under warranty. Light weight was the main selling point, but the above mentioned points were my negatives. 
There seems to have been a reduction in charge rate of 12v with one of the software updates. Initially when first signs of 12v battery failures started to appear, I tested my 12v charge rate and it was close to 15v. Always felt that was high. After I had the 12v replaced, I checked it again and it was closer to 14v. That number alone should allow for a longer lifespan for the 12v.


----------



## JasonF

Jim H said:


> When Lithiums go, they seem to go abruptly, not a gradual decrease in output. Not sure if Lithiums can be jumped started either.


I've known this since I tried putting lithium batteries in an electronic door lock. They work perfect 100%, no warning from unlock motor slowdown, until one day it's completely dead.

Whether or not they can be jump started depends on whether the battery has gone open circuit or not. A jump pack isn't a defibrillator, it's just a 12 volt source.


----------



## GDN

ULEWZ said:


> Mine lasted just 4 months shy of 3 years. Always left on the charger and always garaged. It gave my wife quite the scare when the drivers window went half way down, the screen was black, and she could not open the doors. She called me on her cell from the garage and I had to go out to show her how to open the door manually (yes, I showed her before). Smelled a little rotten eggs from the fronk area, and when the service advisor removed the existing battery, the sides were bulging. NO cost to replace by the way, but the batteries looked identical.


This is not directed at you or your wife, but knowing about and remembering to use that manual release could truly be the difference in life or death based on a wreck or some other situation. I hope all learn about it and remember it.


----------



## JWardell

JasonF said:


> I've known this since I tried putting lithium batteries in an electronic door lock. They work perfect 100%, no warning from unlock motor slowdown, until one day it's completely dead.
> 
> Whether or not they can be jump started depends on whether the battery has gone open circuit or not. A jump pack isn't a defibrillator, it's just a 12 volt source.


I doubt the battery is dead, you are describing how the electronics perform, which like many other items have a low voltage limit at which they shut down in order to protect the battery. Your observations simply just say they lock was better designed within the relatively higher power curve of the lion battery compared to a similar alkaline battery product, and those most certainly can't handle as much power as long, so you notice them getting much slower well before the software in the electronics decides it is time to shut down.
And that doesn't have much to do with a 12v car battery.

It's also not so easy to kill a lion 12v car battery. But what a lot of you seem to mistaking for "dead" is simply when Tesla's software decides to put up an alert, or decides to stop charging the battery. But it's not the battery chemistry to blame, and it's not doing anything wrong.
It's Tesla's software, which monitors and handles its 12v battery in ways no other car does. It measures every bit of energy in and out, and shuts things down when they get suspicious. Because it is specifically made for the lead acid battery they use. Swapping out a different chemistry with different curves is going to confuse it and ask for trouble. Connecting aftermarket loads directly to the battery is also asking for trouble. It's not that it will hurt the physical battery, its that Tesla's software is not written for anything else.

It remains to be seen exactly how Tesla will be handling the new 12v lion battery in the plaid S but you can be sure they are going to use a healthy amount of software wizardry and it will again not be smart to modify it.


----------



## Tchris

Jim H said:


> If your Lithium replacement fails within the 4 year warranty period, you get a free replacement. Good deal unless it fails in middle of no where on a trip. Can't call Tesla to replace non OEM battery under warranty. Get a tow and wait till free replacement Lithium gets sent to you. When Lithiums go, they seem to go abruptly, not a gradual decrease in output. Not sure if Lithiums can be jumped started either.
> just a few things to consider with going Lithium 12v. I was going to go this route as well, until my 12v failed and was replaced under warranty. Light weight was the main selling point, but the above mentioned points were my negatives.
> There seems to have been a reduction in charge rate of 12v with one of the software updates. Initially when first signs of 12v battery failures started to appear, I tested my 12v charge rate and it was close to 15v. Always felt that was high. After I had the 12v replaced, I checked it again and it was closer to 14v. That number alone should allow for a longer lifespan for the 12v.


If your Tesla OEM battery fails in the middle of nowhere, you're pretty much screwed as well. Also, Tesla is now putting Lithium batteries in the Model S and X.


----------



## android04

Tchris said:


> If your Tesla OEM battery fails in the middle of nowhere, you're pretty much screwed as well. Also, Tesla is now putting Lithium batteries in the Model S and X.


True if "middle of nowhere" is a desert or forest or something. But if "middle of nowhere" is a small town with an auto parts store, then they will most likely have a group size 51R lead acid battery to replace whatever 12v battery you had (51R are common in many Hondas).


----------



## Tchris

android04 said:


> True if "middle of nowhere" is a desert or forest or something. But if "middle of nowhere" is a small town with an auto parts store, then they will most likely have a group size 51R lead acid battery to replace whatever 12v battery you had (51R are common in many Hondas).


Well, in that case you're covered whether you have a lithium or lead acid battery right?


----------



## garsh

Tchris said:


> Well, in that case you're covered whether you have a lithium or lead acid battery right?


It's still early days for Lithium 12v batteries. You're unlikely to find a replacement at your local car battery store.


----------



## Jim H

Tchris said:


> Well, in that case you're covered whether you have a lithium or lead acid battery right?


I carry a jumper 12v kit I got at Costco, to give me a jump on the 12v if needed. A jumped lead acid battery should allow you to continue on your way so you can get a replacement. 
Not sure if you can jump a 12v lithium. 
True on the 51R size, which you can usually find at many places.


----------



## JasonF

Technically you can remove the 12v battery entirely, tape a jump pack in its place (don't leave it loose or it will fall off), and attach the clamps to the battery cables (tape them up to keep them somewhat secure), and then drive someplace safe. I wouldn't recommend leaving it that way, but it's possible in an emergency. Even more so in an EV because the underhood area doesn't get hot or vibrate as much.

Another cool Tesla trick that I myself used when my battery died, once you get the car to turn on and the contactors closed (the "thunk" noise from beneath it), turn the A/C on and set it for Climate Keeper or Dog Mode if you have to stop for some reason - even to charge. That will keep the contactors from opening, and you'll have a ready supply of 12 volts the whole way. If you have to stop somewhere for a very long time, use Camp Mode instead, as Climate Keeper will time out.


----------



## Tchris

garsh said:


> It's still early days for Lithium 12v batteries. You're unlikely to find a replacement at your local car battery store.


That is true. But that doesn't mean you can't replace a lithium with a lead acid if you're in a bind. That was my point. If you're on the road and in a remote location, you're in pretty much the same predicament whether you have a lithium or lead acid battery. If you can find a lead acid replacement, you are good to go in either case. If you can't, then your going to have to get a tow, or have a battery brought to you in either case.


----------



## Tchris

Jim H said:


> I carry a jumper 12v kit I got at Costco, to give me a jump on the 12v if needed. A jumped lead acid battery should allow you to continue on your way so you can get a replacement.
> Not sure if you can jump a 12v lithium.
> True on the 51R size, which you can usually find at many places.


I do the same. I haven't had the opportunity to try it yet, thankfully. I am not aware of any problems with jump starting a lithium battery, but then again I don't know for a fact that there aren't. I'll have to look into it.


----------



## Tchris

I c


Tchris said:


> I do the same. I haven't had the opportunity to try it yet, thankfully. I am not aware of any problems with jump starting a lithium battery, but then again I don't know for a fact that there aren't. I'll have to look into it.


I contacted Ohmmu Energy to inquire as to whether or not you can jump start their 12V lithium battery (LiFePO4). The answer from them is "Yes you can". They provided the following additional information:

To further explain; "jump" starting a Tesla is just applying 12V to wake it back up. If the vehicle is working properly the DC/DC will turn on when you turn the car ON and keep the 12V system voltage active.

The only problem with some scenarios is when someone would try to use a 24V jump system, for lead acid it's ok to sit on 24V for a while and it won't do much. In our lithium batteries the charge rate will be very high and it could trip the BMS to turn off. So, be weary of 24V "jump" systems is all.

12V (like from another vehicle) are all gonna be totally fine.

--
Ohmmu Energy
Tempe, AZ 85283


----------



## android04

JasonF said:


> Technically you can remove the 12v battery entirely, tape a jump pack in its place (don't leave it loose or it will fall off), and attach the clamps to the battery cables (tape them up to keep them somewhat secure), and then drive someplace safe. I wouldn't recommend leaving it that way, but it's possible in an emergency. Even more so in an EV because the underhood area doesn't get hot or vibrate as much.
> 
> Another cool Tesla trick that I myself used when my battery died, once you get the car to turn on and the contactors closed (the "thunk" noise from beneath it), turn the A/C on and set it for Climate Keeper or Dog Mode if you have to stop for some reason - even to charge. That will keep the contactors from opening, and you'll have a ready supply of 12 volts the whole way. If you have to stop somewhere for a very long time, use Camp Mode instead, as Climate Keeper will time out.


This might not work with all jump packs, because some don't output anything unless they detect a small voltage from the lead acid battery (i.e. 6V or 4V). Some (like my NOCO GB40 jump pack) have a Boost button that will allow you to bypass that for a certain amount of time. I've actually used that bypass a few times on cars with dead alternators and very low batteries to limp them to a parts store and a big box store.


----------



## garsh

Tchris said:


> But that doesn't mean you can't replace a lithium with a lead acid if you're in a bind.


Probably OK to get the car started, but I wouldn't leave it attached for long. The charging profiles for SLA and LiIon are usually different. Ohmmu LiIon batteries (which are sold as replacements for Tesla SLA batteries) include their own BMS internally that allows them to charge from a source that expects an SLA. But for a Tesla that is designed for a LiIon 12v, I would assume that the charging profile will be designed for a LiIon from the start.


----------



## Tchris

garsh said:


> Probably OK to get the car started, but I wouldn't leave it attached for long. The charging profiles for SLA and LiIon are usually different. Ohmmu LiIon batteries (which are sold as replacements for Tesla SLA batteries) include their own BMS internally that allows them to charge from a source that expects an SLA. But for a Tesla that is designed for a LiIon 12v, I would assume that the charging profile will be designed for a LiIon from the start.


I was just referring to a Tesla Model 3 that has changed over to a lithium battery like the Ohmmu (which I did about a year ago. If I have battery problems on a road trip and the only thing available is a lead acid, I can just swap out the lithium for a lead acid and continue on my way.


----------



## EMC

Does anyone know how much tesla chargers to replace the 12V battery outside of warranty?


----------



## FRC

EMC said:


> Does anyone know how much tesla chargers to replace the 12V battery outside of warranty?


I paid +/-$110 a year and a half ago.


----------



## shareef777

Well, 2.5yrs in and got this message. Was hoping I'd make at least 3 years. Opened a service ticket via the app. What're the odds that they won't cover this under warranty?


----------



## android04

shareef777 said:


> Well, 2.5yrs in and got this message. Was hoping I'd make at least 3 years. Opened a service ticket via the app. What're the odds that they won't cover this under warranty?
> View attachment 40584


I'd say the odds that they don't cover it under warranty are 0%, unless you have more than 50k miles on your car. Then the odds are probably closer to 98%.


----------



## shareef777

android04 said:


> I'd say the odds that they don't cover it under warranty are 0%, unless you have more than 50k miles on your car. Then the odds are probably closer to 98%.


Just got the "invoice". $0, covered under warranty and they threw in a tire check :thumbsup:


----------



## FRC

Tesla replaced the 12v on my 9/2018 M3 P in 2020 after a little less than 2 years and a little more than 50K miles (so it was not covered under warranty). As far as I know the replacement battery was identical to the OEM.

I have begun to see small quirks that may (or may not) be related to 12v failure. My 2nd 12v is now a little less than 2 years old and has a little more than 50K miles, just the same as the OEM was at failure.

I don't recall seeing any discussions about a second 12v failure. Did Tesla change anything to make the replacement 12v last longer than the OEM did, either in the 12v, or in the car itself? Should I continue to expect a 12v failure every +/- 2 years and +/- 50K miles?


----------



## iChris93

FRC said:


> I have begun to see small quirks that may (or may not) be related to 12v failure.


Such as?


----------



## FRC

iChris93 said:


> Such as?


Just returned from an 800 mile trip; At one point I'm on the interstate, TACC engaged at 70 mph when the screen when blank of virtually all info. It still showed my car and the cars around me, and it showed the roadway with the blue lines indicating that TACC was engaged. It showed a yellow park symbol and a red brake symbol, and it had a warning label that said "park assist unavailable". It did not show any of the other normal info like speed, gear selection, etc. After a reboot on the fly, normal operation returned until I stopped to supercharge. When I reversed the car, the screen froze showing the car in drive and a frozen back-up camera image. This kind of "quirk" makes me wonder about 12v failure.

I wish Tesla would design a method for us to easily analyze 12v health at a glance.


----------



## iChris93

FRC said:


> Just returned from an 800 mile trip; At one point I'm on the interstate, TACC engaged at 70 mph when the screen when blank of virtually all info. It still showed my car and the cars around me, and it showed the roadway with the blue lines indicating that TACC was engaged. It showed a yellow park symbol and a red brake symbol, and it had a warning label that said "park assist unavailable". It did not show any of the other normal info like speed, gear selection, etc. After a reboot on the fly, normal operation returned until I stopped to supercharge. When I reversed the car, the screen froze showing the car in drive and a frozen back-up camera image. This kind of "quirk" makes me wonder about 12v failure.
> 
> I wish Tesla would design a method for us to easily analyze 12v health at a glance.


Why attribute to a 12V battery what you can attribute to 💩 software?


----------



## FRC

iChris93 said:


> Why attribute to a 12V battery what you can attribute to 💩 software?


Because the software glitch generally resolves itself; a 12v glitch could leave me stranded somewhere high in the Appalachians!


----------



## FRC

So, back on track...Is my Tesla-supplied replacement 12v just as susceptible to early failure as the OEM was? I'm headed to Alaska in August and I'm thinking I should go ahead and replace again (closer to August).


----------



## EBMCS03

FRC said:


> So, back on track...Is my Tesla-supplied replacement 12v just as susceptible to early failure as the OEM was? I'm headed to Alaska in August and I'm thinking I should go ahead and replace again (closer to August).


It seems like the 12V lasts about 50k miles. Prob the new ones too

Here's some data points of when the original battery dies.
Coworker 2018. 48k miles
Neighbor 2018. 43k miles
Cousin 2018. 52k miles
Mine 2018. Still on original 24k miles.


----------



## iChris93

EBMCS03 said:


> It seems like the 12V lasts about 50k miles. Prob the new ones too
> 
> Here's some data points of when the original battery dies.
> Coworker 2018. 48k miles
> Neighbor 2018. 43k miles
> Cousin 2018. 52k miles
> Mine 2018. Still on original 24k miles.


Here's another data point:
2018 original 12 V with 64k miles.


----------



## garsh

iChris93 said:


> Here's another data point:
> 2018 original 12 V with 64k miles.


I guess I need to start shopping around for a battery.
I'm at 63k miles on my original battery. 🤞


----------



## iChris93

garsh said:


> I guess I need to start shopping around for a battery.
> I'm at 63k miles on my original battery. 🤞


To be clear, mine hasn't failed yet. (Knock on wood).


----------



## GDN

FRC said:


> So, back on track...Is my Tesla-supplied replacement 12v just as susceptible to early failure as the OEM was? I'm headed to Alaska in August and I'm thinking I should go ahead and replace again (closer to August).


Per my observations just 11 months ago from a 12v battery replacement, the replacement is indeed identical to the original. That being said, could they or did they make SW changes that might get longer life out of the 12v, I don't know.

Some comparison old to new:
https://teslaownersonline.com/threads/nikos-and-silent-thunders-excursions.7240/post-309347


----------



## JasonF

GDN said:


> Per my observations just 11 months ago from a 12v battery replacement, the replacement is indeed identical to the original. That being said, could they or did they make SW changes that might get longer life out of the 12v, I don't know.


They did make changes, but I also think the original batteries in the first year or two of Teslas, the manufacturer of them wasn't able to keep up with orders and were shipping marginal condition batteries to keep up, rather than scrapping them.


----------



## GDN

JasonF said:


> They did make changes, but I also think the original batteries in the first year or two of Teslas, the manufacturer of them wasn't able to keep up with orders and were shipping marginal condition batteries to keep up, rather than scrapping them.


Changes when? We know that earlier this year they moved to a Li Ion 12v, but that is not what this is about. Those two batteries from from November 2018 and May 2021. What changes were made in those 3 years. If your older 12 v fails today what are they putting in?


----------



## FRC

JasonF said:


> They did make changes, but I also think the original batteries in the first year or two of Teslas, the manufacturer of them wasn't able to keep up with orders and were shipping marginal condition batteries to keep up, rather than scrapping them.


This is what I'd be very interested in some solid evidence about.


----------



## JasonF

GDN said:


> Changes when? We know that earlier this year they moved to a Li Ion 12v, but that is not what this is about. Those two batteries from from November 2018 and May 2021. What changes were made in those 3 years. If your older 12 v fails today what are they putting in?


The post I quoted referred to software changes. Tesla made a few of those involving the charging pattern for the 12V battery that seems to be protecting its longevity better.

I believe now they might be buying 12V batteries from multiple vendors to keep up with production, so there's a chance if you get a replacement it might be a different brand. And I'm sure after such a large percentage of the 12V batteries failed initially, the manufacturer(s) made changes to chemistry to improve the lives of them, especially if they had to eat some of the cost of replacing them.


----------



## Power Surge

JasonF said:


> The post I quoted referred to software changes. Tesla made a few of those involving the charging pattern for the 12V battery that seems to be protecting its longevity better.
> 
> I believe now they might be buying 12V batteries from multiple vendors to keep up with production, so there's a chance if you get a replacement it might be a different brand. And I'm sure after such a large percentage of the 12V batteries failed initially, the manufacturer(s) made changes to chemistry to improve the lives of them, especially if they had to eat some of the cost of replacing them.


I have the mobile service coming this Friday to replace my 12v battery. I'll post what they bring.


----------



## android04

For anyone wondering about any changes Tesla had made to the lead acid 12v batteries, or the charging and monitoring software in the car. Tesla has changed the charging and monitoring software in the car to try and improve failure detection, but it will never be 100% accurate and will never catch all failure modes before the battery dies. They have also changed the way the car charges the battery, and try to keep the car awake to maintain the 12v system if battery failure is detected or expected.

As for hardware changes on the lead acid batteries, there has been one. They are all made by Hankook AtlaxBX. The very early Model 3s had revision -A of the lead acid battery part number (all cars made up to around March or April 2018). All later cars and all new replacements by Tesla are revision -B. FYI, my Model 3 was made in March 2018 and has the revision -A battery. It's still working fine after over 4 years and 76k miles.


----------



## Power Surge

android04 said:


> For anyone wondering about any changes Tesla had made to the least acid 12v batteries, or the charging and monitoring software in the car. Tesla has changed the charging and monitoring software in the car to try and improve failure detection, but it will never be 100% accurate and will never catch all failure modes before the battery dies. They have also changed the way the car charges the battery, and try to keep the car awake to maintain the 12v system if battery failure is detected or expected.
> 
> As for hardware changes on the lead acid batteries, there has been one. They are all made by Hankook AtlaxBX. The very early Model 3s had revision -A of the lead acid battery party number (all cars made up to around March or April 2018). All later cars and all new replacements by Tesla are revision -B. FYI, my Model 3 was made in March 2018 and has the revision -A battery. It's still working fine after over 4 years and 76k miles.


Mine is also 4 years old with the original battery. Which is why I'm replacing it. lol.


----------



## JasonF

Power Surge said:


> Mine is also 4 years old with the original battery. Which is why I'm replacing it. lol.


I'm keeping a close eye on mine. I replaced it in 2020, close to almost exactly 2 years from when the car was new. But now it's 2022, so this summer there's a possibility it might die again. Sadly, right when the warranty runs out.


----------



## Power Surge

Here is what Tesla Mobile Service installed in my car today....


----------



## ClaudeSutton

We had to replace the battery in my wife's 2019 M3 at 88,000 miles. We did not receive any warning notices at all prior to the failure. I will describe what happened below in the hopes that it might help someone with the same issue.

On 04/18/2022 my wife drove the 40-mile trip from Benton, AR to Hot Springs Village, AR to work without any issues but when she attempted to get into her car at the end of the day using her phone the car would not open, so she attempted opening the doors with the app which also failed. She then called Tesla Support, but they could not open the car or even see it on the network. So, we setup a service appointment in the app but after finding out that they couldn't get to it until 05/05/2022 I decided to just troubleshoot it myself see if I could fix it. I eventually got into the interior of the car by manually opening the passenger's door with a long metal rod, which BTW is extremely easy to do with the design of the manual release on the door. Once I was in the car, I noticed that the interior lights, windows, seats, door locks and even taillights all worked as normal on the right side of the car but nothing else worked in the car at all. I googled those symptoms and found everything from bad VC controllers to bad 12V batteries. Having no clue about how to resolve a bad VC controller I decided to roll the dice with the easy fix and focus on the 12v battery. I used my jump starter to open the frunk and attempted to jump/charge it enough to get it going so I could at get it back to my house. When I attached the jump start it never indicated that it engaged and started charging the battery, so I called it a night and went back home and started researching what replacement battery I need to buy to replace the Atlasbx 85B24LS at my local auto parts stores, as expected they were not very experienced with Tesla replacement batteries and their websites didn't offer much more help. I eventually settled on buying a Duralast Platinum EFB 51R class of battery from AutoZone, This battery was about twice as expensive as the replacement battery that Tesla quoted me but I didn't really want to wait another 2 weeks to get my car back on the road. I eventually installed the battery, and everything seems to be fine. My only concern is how well the battery will hold up long term since it is not an exact match and if the battery could cause any long-term issues to the rest of the car.


----------



## JasonF

ClaudeSutton said:


> My only concern is how well the battery will hold up long term since it is not an exact match and if the battery could cause any long-term issues to the rest of the car.


How does the amp-hour rating compare to the OEM battery? If it's more expensive it probably has a higher rating, which should last longer than the OEM one did.


----------



## shareef777

I wouldn't worry about it. 12V is 12V. As @JasonF said, you likely bought a "larger" battery. Which in an IC vehicle would be beneficial in cold weather for the starter to turnover the engine. Don't really gain much in a Tesla other then longevity.


----------



## francoisp

If the 12 volts battery dies, how do we open the frunk assuming the car is locked?


----------



## android04

francoisp said:


> If the 12 volts battery dies, how do we open the frunk assuming the car is locked?


https://www.tesla.com/support/do-it-yourself-model-3#hood-no-power
This is also relevant https://www.tesla.com/support/do-it-yourself-model-3#jump-start-12v


----------



## Johnk83776

Garlan Garner said:


> Has anyone replaced their 12V battery yet?
> 
> If so...how did you know it needed replacement?


When I picked it up there was a message on the display. So I drove the car for a week until I could get it back to Tesla for a replacement.


----------



## tencate

OK, my 12V battery finally started getting noticed by the car and I got an alert over the weekend that it needed to be replaced. It's a November 2017 battery (over 4 years old) and the car has 120,000+ miles on it. Was replaced with an identical Hankook battery, hope to get another 4+ years out of this one.


----------

