I own a 2017 Model S 100D and my "low 12v battery schedule service to replace (not exact verbiage but you get the jest)" light came on. This will be the fourth 12v battery since I purchased the vehicle new in December of 2017. The last new 12v battery was just installed in April of 2022. I could only schedule an appointment three weeks out and am afraid to drive the vehicle for fear that the battery might die and I won't be able to enter the vehicle. I've tried calling Tesla to get an earlier appointment but am unable to speak to a live person and keep getting referred back to the app. I received a service estimate of $200+ but feel there is an underlining problem that needs to be addressed. Unfortunately the vehicle is out of warranty but I still can't believe Tesla expects me to replace the 12v battery every 9 to18 months. Are the rest for you owners experiencing the same kind of battery issues? If so, what are you or Tesla going to fix the problem?
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12v Battery life
- Thread starter Bigswing
- Start date
ucmndd
Well-Known Member
Super weird. The original 12v battery in my Dec 2016 S went a full 5 years before I proactively replaced it. Second one still going strong.
It seems like each model year and each 12V battery varies greatly. Some knowledgable folks here believe Tesla's 12V system design is to blame and that overcharging is taxing on the battery's longevity. I got about 4 years on the original battery when Tesla replaced it under warranty while changing out the HV contactors. The replacement battery gave off a "low 12V battery schedule service" warning over 8 months and 5K miles ago. The 12V battery still ranges between 12.7-13.7V so I'm not clear on why the warning message has been triggered. I'm not sure how the 12V battery health monitor works or if it's not working properly on my car. Surprisingly our Fiat 500e has 83K miles and 9.5 years on the original 12V battery.
beatle
Active Member
The original 12v in my 2015 made it 5 years, 10 months before I got my warning. Tesla replaced it 2 years ago and the replacement is still fine.
Maybe there is a bad connection somewhere that is causing the voltage on the 12v battery to read low and trigger the fault? This may also cause the car to overcharge the battery and wear it out prematurely.
Maybe there is a bad connection somewhere that is causing the voltage on the 12v battery to read low and trigger the fault? This may also cause the car to overcharge the battery and wear it out prematurely.
vcor
Tech Specialist
I got 5 full years on my 2016S before needing a new battery. That was at about the 35K miles point. If you drive very little, it can cycle the battery more often and cause the life to be reduced. Battery life is mostly based on the number of charge/discharge cycles. Lots of cold or very hot weather can also reduce the battery's life. If none of these seem likely, then perhaps there is a larger-than-normal vampire drain. How many miles do you lose in a day? 2-3 miles is normal, with Sentry mode off and Smart Summon standby (if you have the option) off. If Sentry mode is on all the time, I can see that reducing the battery life quite a bit. There are options to have Sentry mode automatically off at home and/or at work.
2025, Model S RWD. Proactively replaced the battery after 4 years in 2019 (with no low battery warning present). Still on that replacement 4 years later with no warning. There must be something draining your 12v causing excessive cycles that Tesla needs to diagnose.
airborne spoon
Active Member
I bought one 13 Aug 2019, then 18 Nov 2021, and the newest one i bought 4 Nov 2022
I dono if I've gotten one before this because that's as far back as tesla can look in my service history (that's a load of crap)
I dono if I've gotten one before this because that's as far back as tesla can look in my service history (that's a load of crap)
My original lasted for 5 years before I replaced it, I don't have any warnings but I experienced more vampire drain and strange charging behavior, so I replaced it and it solved the issue. You can reset the Tesla, turn off sentry, disable summon, and remove any app - make sure the car goes to sleep to see if it helps, it looks like there is some draining/charging issue with the 12v battery that needs to be investigated by Tesla.
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ATPMSD
Active Member
Just turn Sentry on and remove all exclusions, if any. This will keep the car awake. When the car is awake the battery is not used, only charged.
My 6 year ol Tesla mod X was serviced by Tesla 3 weeks ago, then last week the warning about the 12v battery needs replacing came on. I've read online that this battery is under warranty for 8 years (even on Tesla.com site), but Tesla are claiming it is chargable? I've also see other owners posting elsewhere that they had the 12v replaced FOC when car was over 4 years old and out of general warranty. Any experience with this?
FWIW, I got a battery warning on my 2017 S100D (July 2017 mfg date) in November 2020. Even though the car was still under warranty, I replaced it with an Ohmmu. No trouble since, the car recently passed 90,000 miles.
At that time the car spent most of its time with our daughter’s family since I was telecommuting. They have three young children and I didn’t want them stuck somewhere dealing with a dead 12 Volt battery.
The car is back in our driveway now. They got a Model Y a year later when I warned them my career was ending, I planned to go on a big road trip with the S as soon as I “put down my pencil for the last time” and they would be stuck with a Hyundai So-Not-A (Tesla).
I stayed at work an extra year to support a big project. I was several years past standard retirement age when I left on a downsizing wave with a decent package. Started my road trip a week later.
I haven’t thought about the car’s 12 Volt battery in years.
At that time the car spent most of its time with our daughter’s family since I was telecommuting. They have three young children and I didn’t want them stuck somewhere dealing with a dead 12 Volt battery.
The car is back in our driveway now. They got a Model Y a year later when I warned them my career was ending, I planned to go on a big road trip with the S as soon as I “put down my pencil for the last time” and they would be stuck with a Hyundai So-Not-A (Tesla).
I stayed at work an extra year to support a big project. I was several years past standard retirement age when I left on a downsizing wave with a decent package. Started my road trip a week later.
I haven’t thought about the car’s 12 Volt battery in years.
beatle
Active Member
My 2015 was still under a bumper to bumper warranty and I was charged for the 12v replacement. I didn't fight it as these are generally considered consumable in any vehicle, and I got almost 6 years out of it. The price for Tesla to come replace it and load new BMS code in my driveway was reasonable as well. There are bigger fish.
12v battery is not covered for 8 years. They only cover it for the first 4 years. The main HV battery is covered for 8 years.
So it was almost 6 years?
How was it still within a 4 year warranty period?
This is not explicitly stated on any of Tesla warranty documents. But, the 12v is expected to last ~4 years; and if that happens not to be the case the SC might goodwill it (as it was the case for my car). The 12v is a wear and tear item, like tires.
Yes, I think this is good to point out. The 12V batteries are technically not covered, but in practice, they have almost always goodwilled these through the original 4 years.
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