I'm at 4 years and 91k miles. Still on first battery. I do not regularly use Sentry mode or Cabin Overheat Protection. I also only plug it in a couple times a week to charge, not every time I park in my garage.
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"Proactive" 12v battery replacement - good idea or overkill?
- Thread starter joebruin77
- Start date
SilverString
Member
Mine was changed out by mobile service a few days ago and the tech said there was no visible signs of degradation. My car has a gel battery and there was no mention of returning a core on the invoice. Damn! I should have told him to leave the old battery as I most certainly would have had some use for it.
FloridaGary
Member
You can also find threads here where they throw alerts after Tesla updated their software and see a Lithium battery as a "broken" 12V Lead Acid, because it is. Right now Ohmmu is not selling batteries until they can figure out how to fix this.
Longer term Ohmmu experiences?
Hi Looking at possibly buying an Ohmmu lithium (LiFePO4) battery to replace the OEM one in my Model 3. The car is approx 18 months old and from what I can see from stats it has started waking up to top up the 12v battery every 24 hours, so I don’t think it’ll be too long before it says it needs...teslamotorsclub.com
Thanks! I was not aware of this. I have a 2018 Model 3 and I think it will work for me, but not sure of the newer models.
Nope. The same firmware update "broke" all cars that used a lead acid battery (2017-2022).
FloridaGary
Member
There have been a great deal of discussions about 12 Volt battery replacement, which kind to use, when to do it and proactive or not. Here is my most recent experiences and what I have learned.
First, when my model 3 was new in 2020 I replaced my 12 volt AtlasBX with an Ohmmu. The idea of having a lithium battery that could run for years vs. a basic lead acid seemed an easy decision. The Ohmmu worked flawlessly for months until Tesla started messing with the charging software.
Ohmmu developed a fix and replaced batteries. Well done.
Then Tesla hired a 12 volt battery engineer (Ohmmu knows the name of the engineer) who decided to add a battery over charge test to the software. The Ohmmu's Battery Management Computer (BMC) seeing the over voltage during the test would disconnect the Ohmmu to protect it (as it should) for about 5 minutes. But this caused multiple error messages. Back to the drawing board.
Ohmmu issued version or gen 3 of the Ohmmu. Many have stated worked great than about a month (including myself) then suddenly all kinds of messages again. Ohmmu is now working on Gen 4. My understanding is preliminary tests good expanding test group.
In the mean time, since I still had my factory AtlasBX on the shelf (now 2 years old but only cumulatively 10 days worth of usage) I charged it up (still had 95%) put a tester on it, it tested good and reinstalled while waiting for an Ohmmu fix. Messages gone and no warnings.
About 2 weeks after the install of the AtlasBX, I was having work done (seasonal brake maintenance) and was told by Tesla some battery messages were noted and they were going to "Proactvely" replace my AtlasBX. None noted by me either as warnings or notifications but maybe there is something they see that I can't. Battery replaced - no charge.
Which now raises the question:" How reliable is the AtlasBX". Now before everyone piles on with success stories there have been too many that have posted that warning to failure was either minutes to a day or so. That got me wondering if while waiting for a Ohmmu solution (I still think Lithium is the best way to go - so did Tesla on later 3/Y builds) what would be the best battery choice should it take months for an Ohmmu solution? AGM, EFB, or regular lead acid battery? AGM's are built for cycling (they are used on cars for example the have start/stop features even some have alternates that go offline until a certain voltage drop then re-engage to charge things back up to help mileage). EFB batteries are like a hybrid - they are a lead acid but designed for greater cycling. Then standard lead acid batteries (size 51R is what is needed). If one looks at the owners manual under specifications it will say the 12 volt must be 33 Amp/Hr rating or greater. The AtlasBX is 45 (and 625 CCA although CCA is not needed).
I was at Electrified Garage yesterday in NH (knowledgable good folks there). I asked which alternative battery to Ohmmu (which they used to install). I discussed the EFB (Enhanced Flooded Battery - see AutoZone for an example). AGM and regular. I pointed out that Orielly's for example published on the AGM it needs 13.8-14.6 volts to charge and 13.4 to 13.6 volts to float voltage. Otherwise with testing or monitors on the 12 volt have reported the charge voltage is 14.55 and the float is 13.1-13.2. The EFB had no such limits. So I asked the question to Electrified Garage "If a customer came in right now what battery would you put in?" Without hesitation the answer was "AGM". But I said "What about the charging requirements?" There answer: "the AGM is designed to cycle and all that will happen is the total charge will drop and at some point the cDC-DC charger will step up and recharge it". They had done some Tesla retrofits for a police department and got errors with the AltlasBX was loaded with accessories so they swapped out to AGM and no more warnings. I asked if others that had the AGM installed had any warnings and the answer was "no". They also said the Model 3 float charges to about 13.5v and Tesla has been trying to get the software right for charging since the Model S.
Another poster in a different thread stated he had gone to Orielly's because it was a weekend and put in an AGM a while ago. After something like 3 years 50,000 miles finally replaced it as a matter of routine maintenance. I think he replaced with the AtlasBX.
So yesterday I decided to put the AtlasBX on the shelf (as a backup) and install an AGM. I chose Orielly's but any of them meet spec of exceeding 33 Amp/Hrs. So far, no warnings (other than the ones that occur during removal process). Checked today, nothing overnight either. Prior to install, it was a 95% as delivered so I charged to 100% and tested. Tested good. We shall see but I have more confidence in the AGM than the AtlasBX while waiting for the Ohmmu solution.
So in conclusion I am running an AGM while waiting for the Ohmmu solution. As I has said earlier, I still think a lithium like Ohmmu is the best solution but at least I have more confidence in the AGM than the AtlasBX. I would caution that if Ohmmu had BMC issues, other lithiums SHOULD have the same problem as they all use a BMC. Some are claiming "no warnings" with their Lithium batteries but I will wait for an Ohmmu solution.
First, when my model 3 was new in 2020 I replaced my 12 volt AtlasBX with an Ohmmu. The idea of having a lithium battery that could run for years vs. a basic lead acid seemed an easy decision. The Ohmmu worked flawlessly for months until Tesla started messing with the charging software.
Ohmmu developed a fix and replaced batteries. Well done.
Then Tesla hired a 12 volt battery engineer (Ohmmu knows the name of the engineer) who decided to add a battery over charge test to the software. The Ohmmu's Battery Management Computer (BMC) seeing the over voltage during the test would disconnect the Ohmmu to protect it (as it should) for about 5 minutes. But this caused multiple error messages. Back to the drawing board.
Ohmmu issued version or gen 3 of the Ohmmu. Many have stated worked great than about a month (including myself) then suddenly all kinds of messages again. Ohmmu is now working on Gen 4. My understanding is preliminary tests good expanding test group.
In the mean time, since I still had my factory AtlasBX on the shelf (now 2 years old but only cumulatively 10 days worth of usage) I charged it up (still had 95%) put a tester on it, it tested good and reinstalled while waiting for an Ohmmu fix. Messages gone and no warnings.
About 2 weeks after the install of the AtlasBX, I was having work done (seasonal brake maintenance) and was told by Tesla some battery messages were noted and they were going to "Proactvely" replace my AtlasBX. None noted by me either as warnings or notifications but maybe there is something they see that I can't. Battery replaced - no charge.
Which now raises the question:" How reliable is the AtlasBX". Now before everyone piles on with success stories there have been too many that have posted that warning to failure was either minutes to a day or so. That got me wondering if while waiting for a Ohmmu solution (I still think Lithium is the best way to go - so did Tesla on later 3/Y builds) what would be the best battery choice should it take months for an Ohmmu solution? AGM, EFB, or regular lead acid battery? AGM's are built for cycling (they are used on cars for example the have start/stop features even some have alternates that go offline until a certain voltage drop then re-engage to charge things back up to help mileage). EFB batteries are like a hybrid - they are a lead acid but designed for greater cycling. Then standard lead acid batteries (size 51R is what is needed). If one looks at the owners manual under specifications it will say the 12 volt must be 33 Amp/Hr rating or greater. The AtlasBX is 45 (and 625 CCA although CCA is not needed).
I was at Electrified Garage yesterday in NH (knowledgable good folks there). I asked which alternative battery to Ohmmu (which they used to install). I discussed the EFB (Enhanced Flooded Battery - see AutoZone for an example). AGM and regular. I pointed out that Orielly's for example published on the AGM it needs 13.8-14.6 volts to charge and 13.4 to 13.6 volts to float voltage. Otherwise with testing or monitors on the 12 volt have reported the charge voltage is 14.55 and the float is 13.1-13.2. The EFB had no such limits. So I asked the question to Electrified Garage "If a customer came in right now what battery would you put in?" Without hesitation the answer was "AGM". But I said "What about the charging requirements?" There answer: "the AGM is designed to cycle and all that will happen is the total charge will drop and at some point the cDC-DC charger will step up and recharge it". They had done some Tesla retrofits for a police department and got errors with the AltlasBX was loaded with accessories so they swapped out to AGM and no more warnings. I asked if others that had the AGM installed had any warnings and the answer was "no". They also said the Model 3 float charges to about 13.5v and Tesla has been trying to get the software right for charging since the Model S.
Another poster in a different thread stated he had gone to Orielly's because it was a weekend and put in an AGM a while ago. After something like 3 years 50,000 miles finally replaced it as a matter of routine maintenance. I think he replaced with the AtlasBX.
So yesterday I decided to put the AtlasBX on the shelf (as a backup) and install an AGM. I chose Orielly's but any of them meet spec of exceeding 33 Amp/Hrs. So far, no warnings (other than the ones that occur during removal process). Checked today, nothing overnight either. Prior to install, it was a 95% as delivered so I charged to 100% and tested. Tested good. We shall see but I have more confidence in the AGM than the AtlasBX while waiting for the Ohmmu solution.
So in conclusion I am running an AGM while waiting for the Ohmmu solution. As I has said earlier, I still think a lithium like Ohmmu is the best solution but at least I have more confidence in the AGM than the AtlasBX. I would caution that if Ohmmu had BMC issues, other lithiums SHOULD have the same problem as they all use a BMC. Some are claiming "no warnings" with their Lithium batteries but I will wait for an Ohmmu solution.
srs5694
Active Member
Is it possible that Tesla service was seeing the error messages that had been thrown by your Ohmmu batteries? If they didn't know you'd installed and then replaced that third-party part, then they would (quite reasonably) think something was bad with the battery that was in the car at the time of service.
I've told you 5 times now this story is wrong and untrue. If you put a LFP battery on a Model 3 without ANY BMS, it still throws codes. Also, LFP can safely be charged to voltages way above what Tesla goes to. Yet you keep posting walls of text like you have some amazing insight and you're the Ohmmu whisperer, which reads more like an ad for Ohmmu than useful information.
What a jerk move. Clearly those messages were all the ones from the Ohmmu you had installed, not the Atlas. This is EXACTLY why Tesla doesn't want to support aftermarket products, it ends up costing them money when customers come to them and complain.
Man what a weird fetish for ANYTHING different than what Tesla engineered in. Like you called out, AGM requires different voltages than flooded. Yet again, you are putting the wrong battery in your car, thinking you are making it more reliable when you are making it less reliable.
Flooded lead acid is designed to cycle too. It's just not designed to cycle to low SoC's. Why do you you think Tesla considers any battery that is below 70% SoC to be trash? Got a chart showing how much more "reliable" AGM is than flooded when never cycled below 70%? What is a flooded battery even for if no cycling is allowed? Every engine start on an ICE car is a cycle.
Can you post a link to even one of these stories in the last 6 months?
Given the time, energy, and massive concern you seem to have for this topic, I think it might be cheaper for you to just go trade in for a new Tesla with the new Lithium Cobalt 15V battery. Or even better, choose a different brand given how little you trust Tesla's engineering.
yeah. I have a hard time seeing a R51 AMG from O'Reilly's which - was NOT designed for use in any EV let alone Tesla - being superior to a engineered special battery for the Model 3. If anything - the car won't correctly cycle or load your off the shelve battery from O'Reilly correctly. I would consider a R51 as interims solution only until i can get the correct Tesla battery installed. They are also not exactly cheap - A R51 AMG from O'Reilly is $200+ whereas Tesla will install a new (and warrantied) 12V battery for just over $100. Throwing a lithium battery into a car with a BMS not designed for lithium is another "odd" move. Especially when you can get over 3x original Tesla 12V batteries incl. installation for the cost of just one (!) Ohmmu battery.
I did buy a second Tesla a 2022 Model Y. This has been my experience I wanted to share for information.
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What is your "experience"? You keep throwing changes at the car and getting errors and worrying about the stock lead acid failing. Yet your lead acid has NEVER failed on you, while the LFP has caused you all sorts of hassles, yet you still are convinced it's better, and that an AGM will be better with no evidence. All in the face of the fact that you could just drop a stock battery in every two years for $100 and be way ahead.
Outside of actually having to remove the Ohmmu, these are not "experiences" - these are "concerns" and "theories".
I noticed you didn't link to anyone having the 12V fail unexpectedly in the last 6 months, despite claiming it happens all the time.
I think "proactive" change of the 12V maybe a good idea. My 2017 MX 12v failed without warning after about 2.5 years. My 2018 M3 12v gives a warning to change it just under 4 years last week. At this point, I think I will start to worry if I don't see a warning message after 3 years on a new 12v. Yeah the 12v may last 4 or 5 years, but at $125 mobile service (which is actually the same price as my old car's sync oil change every 6 months), I think I can afford to do it every 3 years just thinking of it as routine maintenance.
Tesla's 12V detection method on a Model X in 2019 has nothing to do with their detection method on a Model 3 in 2022.
My 2018 Model 3 battery is super healthy (based on checking it outside of the car) 3.5 years later.
The detection method may have improved, however, my Model 3 currently is still sitting in my driveway currently until Father's day morning because that's the soonest Tesla Mobile could come out to change it. I could drive it with the warning message, but I really don't want to get stuck if the 12v decided to eat it when I am out there. When my MX was battery was changed in 2019 or 2020 (don't remember which year), I asked the tech how long does a normal Tesla battery last. He said 3 to 4 years on average. He did say the MX is the worst of them on 12V. He said mine actually doesn't look too bad just a little bulk up. He said he has seen really bad ones that is ready to explode and smell like rotten eggs.
So I will probably set calendar events to change the MX in early 2023 and M3 in summer 2025.
Two weeks ago my wife called me at work to say the car wouldn't start and the screen was black. She did a hard reset and it came back after a few minutes. I got on the app and made an appt to have the 12V replaced even though the car is just under 18 months old. Ten days later the 'replace 12V battery soon' message appeared but the car continued to drive fine. It wouldn't do a s/w update though. Mobile service replaced it yesterday and because the message had appeared it was covered under warranty.
if that's in fact the case ... Tesla will pay for nearly every produced car with one mobile tech dispatch and 12V battery swap on their dime during the 4yr warranty period (assuming you aren't over 50k miles). doesn't seem true or sustainable as a component life. My guess is that under normal circumstances most batteries don't fail under 4yrs or 50k miles... 2018 and 2019 production cars are at the 3-4 yr mark and we would be reading about hundreds of issues here...
Modern firmware versions don't let this happen. Once you have the message that the 12V is bad, it stops going to sleep, which is the only time it needs a 12V battery. Even if the 12V dies, the car will be OK.
The old case of a "dead car" happened when the 12V died while the car was asleep, which meant it couldn't wake up.
The 12V battery can't cause this. She was able to unlock the car and get in, which means the 12V was working. Did you really have to do a hard reset (brake pedal, doors closed, etc), not a soft one? A soft reset only reboots the center screen, which again has nothing to do with the 12V.
Sounds like a simple software bug in the infotainment.
Oh I didn't know that. If that is really the case, then I would drive it. Good to know. Maybe I didn't really have to switch my "pick up" lunch order yesterday to "doordash" when I realized that my wife took the other Tesla out and I can't pick up my lunch. LOL.
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