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12v Battery Options - Which is best?

IchDochNicht

Member
Sep 4, 2016
300
210
Bay Area, CA
I am getting the 12v Battery needs service message, and am weighing my options.

Which of the following have you tried and would recommend as a better option than just letting a Tesla ranger replace it:

1. Gruber Tesla Model S Battery ($138.50 plus $30-80 for shipping)
2. Ohmmu Lithium Battery ($419, no shipping)

How does the chemistry of the Gruber battery differ from OEM?

The Ohmmu would have to last a minimum of twice as long, if not three times as long as the Gruber or OEM battery to be feasible. Is that a realistic expectation - particularly given that the car sits most of the time and is just driven for getting groceries once a week and for a long 500 mile trip every few months.

The original battery lasted almost 5 years.

Thanks!
 

Ostrichsak

Active Member
Sep 6, 2018
3,325
3,283
Colorado, USA
This has been covered ad nauseum and never has concrete evidence been presented that Lithium 12v batteries last any longer let alone the 3x longer required just to break even. Nor do they provide any advantages during their operational life over the $138 OEM battery. To the contrary, if you end up with issues with your 12v system while using an aftermarket 12v battery Tesla can void the warranty of related components citing the battery as the cause.

In a Tesla, all a 12v battery does is run small accessory devices like the MCU, headlights, interior lights, turn signals, etc. Compared to what the 12v battery is required to do in an ICE car (think starting the engine at very cold temps) to say this is "light duty" doesn't even fully capture the difference between these two applications.

Not to mention the Tesla keeps the battery at optimal SoC even when not running whereas an ICE car requires the engine be running to charge the battery via the alternator. Whenever this accessory isn't spinning the battery is discharging all-the-while. They sit for days sometimes discharging and then (in minus zero temps sometimes) are expected to provide an absurd amount of instant amperage draw to physically turn over a large internal combustion engine.

This is why the Cold Cranking Amps (CCA) is probably the most important metric when shopping for a new 12v battery... especially in cold climates. This metric means absolutely nothing in a Tesla to give you an idea how different of an application we're talking.

In an ICE car, there is no way to predict when that battery will suddenly not be able to provide the necessary juice to make the car run and it generally fails in the coldest and most dangerous of scenarios. There's too many variables and the ability to provide CCA tends to drop off rapidly once it nears the end of it's life. This isn't the case with a Tesla. The amps required to power headlights or a stereo are fractional by comparison and the car can monitor the health of the battery at a finite level. This battery health monitoring algorithm tends to err on the side of safety when it comes to warning of an impending failure and most can go weeks or even months once that warning has been issued. It's all-but-eliminated the potential for becoming stranded due to a 12v battery failure so for a few rare outlier cases.

Naturally, people are fearful of being "stranded" in the middle of the night, in the dead of winter and in the most inconvenient time possible. This is a good fear to have and it's based largely on our experience with ICE cars in which this fear is founded in reality. Manufacturers of 12v Lithium batteries prey on this fear since it's unrealistic in a Tesla. They try to get you to pay for something that will do you zero good in a Tesla and, if your fear is being stranded, could potentially even increase the odds of this happening due to the system not being able to properly monitor & manage the health of your 12v battery they way it was designed to do with the OEM chemistry.

The new cars will come with a lithium-based 12v battery but it will include thermal management & cell health management technology that was created for their battery packs. It will be properly engineered and accounted for within the Tesla electronics ecosystem unlike these Band-Aid slapped on Li-Ion 12v aftermarket "solutions" but I'm sure we'll see more and more people asking about it once the new cars start rolling out. Just know that there is a LOT of engineering resourced going into making that an OEM solution so it's silly to think you can just slap one in something as complex as a Tesla w/o any accounting for it via the firmware.

My last warranty replacement 12v battery (I'm still amazed Tesla will replace these under warranty when every other car manufacturer treats them as a "wear item" like the brake pads... I digress) they had a "newer & better version" which was similar in overall chemistry but from a new supplier. This required a change to my car's firmware to properly account for what was the same basic battery. Think about that for a minute. Do you seriously think that if changing to something as different as a lithium chemistry 12v battery you wouldn't need to account for a change that extreme in the car's management system if one is required for what basically amounts to the same battery? When I saw that even going from previous versions of the OEM battery to the newer versions required a firmware change to account for even these minor differences within the system it shed some light on how bad of an idea going with something as different in chemistry as a lithium battery for the 12v system is at any cost.

In short, anyone who says that a $400+ lithium 12v battery is an "upgrade" in any way for a Tesla is selling you snake oil. Don't fall for it.

tl;dr Stick with the OEM and file this conversation under crap not even worth wasting your time considering.
 

Dukeybootie

Member
Nov 12, 2015
201
119
United States
Which option is best depends on the following:

-how often you drive, how far your trips usually are, and how long your car tends to sit unused
-how long you plan on keeping your car
-your budget

Not here to argue with other posters (that's been done before).

I might suggest a separate thread asking people who actually have the Ohmmu battery installed how they are liking it so far, and whether they would recommend it to other people. I'm sure there are enough of us here in the Model S forums to give you some feedback, and plenty more in the Model 3 forums.

When I buy something, I tend to rely more on reviews from people who actually have bought and lived with the product. But that's just me.

2015 85D
Ohmmu installed 1/2020
~20,000 miles driven since with zero problems, zero error messages, zero compatibility issues
Would I buy again/recommend: yes, so far

Consider this one data point and nothing more/less. Cheers to all.
 

Ostrichsak

Active Member
Sep 6, 2018
3,325
3,283
Colorado, USA
Which option is best depends on the following:

-how often you drive, how far your trips usually are, and how long your car tends to sit unused
-how long you plan on keeping your car
-your budget

Not here to argue with other posters (that's been done before).

I might suggest a separate thread asking people who actually have the Ohmmu battery installed how they are liking it so far, and whether they would recommend it to other people. I'm sure there are enough of us here in the Model S forums to give you some feedback, and plenty more in the Model 3 forums.

When I buy something, I tend to rely more on reviews from people who actually have bought and lived with the product. But that's just me.

2015 85D
Ohmmu installed 1/2020
~20,000 miles driven since with zero problems, zero error messages, zero compatibility issues
Would I buy again/recommend: yes, so far

Consider this one data point and nothing more/less. Cheers to all.
See what I mean? Supporting posts have ZERO actual advantages because there are none. The manufacturer doesn't even warranty the battery to last any longer than an OEM battery will to at least get you to a break-even point on investment.

Your 12v battery works. Great. Mine does too but for 1/3 the cost.

There's your difference between OEM and aftermarket 12v batteries summed up. Anyone who tells you any different is trying to convince you for personal gain or themselves because admitting you were duped our of your money publicly is difficult.

Don't act like there's secret advantages like your blinkers flash better because you spend over $400 on a 12v battery.
 

Silicon Desert

Active Member
Oct 1, 2018
3,265
2,968
Sparks Nevada / GF 1
Which option is best depends on the following:
-how often you drive, how far your trips usually are, and how long your car tends to sit unused

Hmmm, I am not so sure about that. Sure, this matters with a typical ICE car since nothing maintains a charge on the battery when it sits, yet my understanding about the Tesla is that the battery is maintained at a range of charge by the main battery pack. I'm just making an assumption. I guess I have to ask someone at the factory about it.
 

Ostrichsak

Active Member
Sep 6, 2018
3,325
3,283
Colorado, USA
Hmmm, I am not so sure about that. Sure, this matters with a typical ICE car since nothing maintains a charge on the battery when it sits, yet my understanding about the Tesla is that the battery is maintained at a range of charge by the main battery pack. I'm just making an assumption. I guess I have to ask someone at the factory about it.
No, you're right. There is no advantage despite what that posted was insinuating about a couple of "advantages" which is the exact way these 12v lithium battery in a Tesla threads go with people making tepid insinuations with zero factual independent data to back up any of the claims of superiority. Just a bunch of people who are suckers for marketing and catch phrases that want the "best" for their cars. Probably put premium gas in their ICE car that was tuned from the factory for regular unleaded because it was "better" too. ROFL
 

Watts_Up

Active Member
Mar 4, 2019
3,154
2,097
In a galaxy far, far away
The new cars will come with a lithium-based 12v battery but it will include
thermal management & cell health management technology that was created for their battery packs.

It will be properly engineered and accounted for within the Tesla electronics ecosystem unlike these Band-Aid slapped on Li-Ion 12v
aftermarket "solutions" but I'm sure we'll see more and more people asking about it once the new cars start rolling out.

Just know that there is a LOT of engineering resourced going into making that an OEM solution so it's silly to think
you can just slap one in something as complex as a Tesla w/o any accounting for it via the firmware.
How did you find this information? Do you have any web link?

I believe that Tesla will use OEM available 12 V Lithium-Batteries like the following one used by Porsche,
but I doubt that there will be any thermal management, as this would be quite complex to add?

Note: Porsche provides an original Lead battery for cold climate areas.

porsche_lightweight-battery.jpg
 
Last edited:

Ostrichsak

Active Member
Sep 6, 2018
3,325
3,283
Colorado, USA
How did you find this information? Do you have any web link?

I believe that Tesla will use OEM available 12 V Lithium-Batteries like the following one used by Porsche,
but I doubt that there will be any thermal management, as this would be quite complex to add?

Note: Porsche provides an original Lead battery for cold climate areas.

porsche_lightweight-battery.jpg
You want me to produce data for something that doesn't even exist yet?
 

Kaveman

Member
Oct 27, 2020
23
9
FL
My 13 MS P85 is on it's 3rd battery. I put in an OhmMu this time around as the last one made it exactly one year before giving the "12V battery" error. It is definitely Expensive, but I haven't had an issue so far. I believe it has a 3 year warranty... So buy a lead acid every year for $100US or so(plus the pain of install... it is a 13), or... have one that is supposed to last 3 years and is Way lighter/easier to install "to boot"...... We will see in time which works out.
Another $.02 on this touchy subject.
 

Silicon Desert

Active Member
Oct 1, 2018
3,265
2,968
Sparks Nevada / GF 1
This thread makes me think it might be time for me to evaluate if I should replace the battery on one of my cars (2017 X) before I start taking another cross country trip later this summer. It's going on 4 years now.
 

animorph

Active Member
Apr 1, 2016
2,133
1,529
Scottsdale, AZ
I had to replace the OEM battery on our March 2017 Model X in August 2020, about 3.5 years. Which is pretty good for Arizona. I got the battery warning, but the car still seemed drivable. It was quicker, and easier to replace it with an Ohmmu rather than wait for Tesla Service. Hopefully it will last much longer, but no one has had an Ohmmu long enough give us data on that.
 

Silicon Desert

Active Member
Oct 1, 2018
3,265
2,968
Sparks Nevada / GF 1
Good article and I thought you might say weather related. While i generally agree, that article is mostly about ICE cars and heat generated by the engine in addition to outside heat. My personal experience is that over 50 years of living and driving in various parts of the USA, I haven't noticed a great difference in the life of a battery. I've had to replace all of the at roughly the 4 year range. Thanks for the link.
 

Ostrichsak

Active Member
Sep 6, 2018
3,325
3,283
Colorado, USA
My 13 MS P85 is on it's 3rd battery. I put in an OhmMu this time around as the last one made it exactly one year before giving the "12V battery" error. It is definitely Expensive, but I haven't had an issue so far. I believe it has a 3 year warranty... So buy a lead acid every year for $100US or so(plus the pain of install... it is a 13), or... have one that is supposed to last 3 years and is Way lighter/easier to install "to boot"...... We will see in time which works out.
Another $.02 on this touchy subject.

Your math is faulty. If you had a 2013 that got 3.5 years on average per battery before the one 1-year battery, wouldn't you assume that one is an outlier? Why would you base your decision off of that ONE experience? Doesn't seem like a very scientific conclusion to me. If it were me, I'd chalk that one up to the bad batches that were rolling out of Tesla for a bit (widely documented around the forums) and assume that the other two batteries that lasted 3.5 years on average were more indicative of the average life. Especially when most people on the forums are talking about 4+ years per battery.

I, myself, have had two cars that needed the 12v replaced (under warranty) that I bought used and both made it around 5-years. This random person posting about 1 year or less is just that... random. A statistical anomaly that's easily explained by the fact that Tesla was sourcing them from a supplier that had poor QC (par for the course when you're sourcing from the lowest bidder to meet the $35k Model 3 they were trying to achieve) and even changed up the battery they've been putting in new cars and warranty replacements. They were different enough to require a new firmware management change.

Even if you average in that one 1-year outlier, your average life for the $140 battery is still almost 3-years. In order that whiz-bang lithium battery you opted for to break even it will have to last NINE YEARS. There is absolutely no data that will support that these lithium 12v batteries will last any longer than OEM let alone 3x longer to justify the price. Remember, there's ZERO improvement on function in a Tesla during it's lifespan so the only way your investment pans out is if that sucker lasts a decade or more. Spoiler alert: it won't.

It's only a touchy subject because I'm not willing to let people like you get duped by bunk marketing that is supported by zero independent scientific data. Zero. When I call out the BSers on their BS they lash back thinking I'll recoil and acquiesce to their banging on their chest. That's not going to happen because I've got the facts and data on my side so... no need.

Face it, lithium 12v batteries in Tesla offer no advantages over OEM 12v batteries.
 
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Ostrichsak

Active Member
Sep 6, 2018
3,325
3,283
Colorado, USA
This thread makes me think it might be time for me to evaluate if I should replace the battery on one of my cars (2017 X) before I start taking another cross country trip later this summer. It's going on 4 years now.
No sense replacing it proactively. The car will let you know well in advance and you'll have numerous places to have it replaced even in the unlikely event that the error message comes on as soon as you set out. Replacing a 12v battery in a Tesla just because it's 4-years old is a lot like changing your motor oil and filter in an ICE car every 500 miles to "be safe" because all you're doing is wasting good oil and $$.
 

Ostrichsak

Active Member
Sep 6, 2018
3,325
3,283
Colorado, USA
I had to replace the OEM battery on our March 2017 Model X in August 2020, about 3.5 years. Which is pretty good for Arizona. I got the battery warning, but the car still seemed drivable. It was quicker, and easier to replace it with an Ohmmu rather than wait for Tesla Service. Hopefully it will last much longer, but no one has had an Ohmmu long enough give us data on that.
You could have easily scheduled to have Tesla come replace it for you long before it would have ever failed fully leaving you stranded. It would have cost 1/3 as much and you wouldn't have even had to lift a finger. Another 3.5 years w/o doing more than clicking a few buttons on the Tesla app and paying $140. Everything else seems foolish. If your car was a 2017 my guess is they would have even just done it for free. Why anyone would order a $420 battery to replace themselves, wait for it to arrive, do the work to install it and then have a battery that will likely last the same amount of time as the battery that costs 1/3 the price is beyond me.
 

Ostrichsak

Active Member
Sep 6, 2018
3,325
3,283
Colorado, USA
Good article and I thought you might say weather related. While i generally agree, that article is mostly about ICE cars and heat generated by the engine in addition to outside heat. My personal experience is that over 50 years of living and driving in various parts of the USA, I haven't noticed a great difference in the life of a battery. I've had to replace all of the at roughly the 4 year range. Thanks for the link.
This is the same for the vast number of motorists across the country despite what a few online would have you believe. There was also a rather sizeable bad batch of 12v batteries put in all Tesla vehicles starting shortly after production of the Model 3 which has soured many people on the OEM batteries. This has long since been addressed with a new supplier and even a change of how the new battery is managed via the firmware. That's why it's necessary to get the firmware adjustment whenever you get the new version of the OEM battery from Tesla.

What version of the Tesla 12v battery management firmware do you think is necessary for an aftermarket lithium 12v battery? That's a rhetorical question because Ohmmu doesn't even know. This in and of itself should be a gigantic red flag for any Tesla owner who is considering one of these.

Hard pass even if they were the same price.
 
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