Used Model Y dash says “schedule service for low voltage battery” - is it okay to buy?

[mra1991]

I’m looking to purchase a used Tesla Model Y. I’m not sure things to look out for while purchasing a used model y. Any tips on this will be greatly appreciated. Also, is it concerning that the vehicle has that “Schedule service for low voltage battery”? It seems like it’s not a big deal but would love to know. Also this particular vehicle doesn’t have the OEM wheels. Can I bargain pricing for that?

 

[jcanoe]

I’m looking to purchase a used Tesla Model Y. I’m not sure things to look out for while purchasing a used model y. Any tips on this will be greatly appreciated. Also, is it concerning that the vehicle has that “Schedule service for low voltage battery”? It seems like it’s not a big deal but would love to know.

That is a warning that the Tesla vehicle's 12V battery needs to be serviced, replaced. The 12V battery is covered by the 48 month new vehicle warranty so it should not cost you anything to have Tesla replace the 12V battery. When the low voltage message appears you have a few weeks (in theory) to get the 12V replaced before the Tesla vehicle won't start up or could even stop running while driving.

(Check with the Tesla Service Center near you but in the past this service costs ~$140 for Tesla Mobile Service (Ranger Service) to come to you and replace the 12V battery if not covered under the warranty.)

Until recently this 12V was a 40Ah deep cycle flooded lead-acid battery that powers things like the door locks, BT, LTE modem and the alarm when the Tesla vehicle is powered down (sleep mode) Tesla recently changed to using a 12V, 7.5Ah, lithium battery module (actually measures 15.5V) in late 2021 and now for all new 2022 Tesla vehicles. It remains to see how well the new 12V lithium battery module performs over time.

 

[mra1991]

That is a warning that the Tesla vehicle's 12V battery needs to be serviced, replaced. The 12V battery is covered by the 48 month new vehicle warranty so it should not cost you anything to have Tesla replace the 12V battery. When the low voltage message appears you have a few weeks (in theory) to get the 12V replaced before the Tesla vehicle won't start up or could even stop running while driving.

(Check with the Tesla Service Center near you but in the past this service costs ~$140 for Tesla Mobile Service (Ranger Service) to come to you and replace the 12V battery if not covered under the warranty.)

Until recently this 12V was a 40Ah deep cycle flooded lead-acid battery that powers things like the door locks, BT, LTE modem and the alarm when the Tesla vehicle is powered down (sleep mode) Tesla recently changed to using a 12V, 7.5Ah, lithium battery module (actually measures 15.5V) in late 2021 and now for all new 2022 Tesla vehicles. It remains to see how well the new 12V lithium battery module performs over time.

Thank you for the detailed reply. This is a 2021 model so I’m assuming I will get it replaced for free finger crossed.

Any other tips you have for used vehicle? Things to look out for?

 

[jcanoe]

Thank you for the detailed reply. This is a 2021 model so I’m assuming I will get it replaced for free finger crossed.

Any other tips you have for used vehicle? Things to look out for?

Tesla's history with 12V flooded lead-acid batteries has been bumpy. Initially Tesla was probably overcharging the 12V batteries, literally cooking them. Over time Tesla has refined the 12V battery charging and maintenance protocol so that the 12V battery will probably last 2 to 3 years, depending on average ambient temperature and other factors. The 12V was always easy to access in the Model 3, Model Y and took more labor to access in the Model S, Model X. In addition to literally "getting the lead out" I'm sure Tesla's decision to switch to the 12V lithium battery module is for reduced service calls. (VW is switching to a similar 12V lithium battery in the ID.4 for 2022.)

 

[e645824]

To add to what jcanoe said, if you do buy that used car, get a new 12V battery IMMEDIATELY. Even if you have to go to Walmart and buy a $90 battery yourself. It is really really dumb, but if that 12V lead-acid battery fails, it is difficult to do anything with the car. i.e. Can't open the doors. Can't put the car in neutral. And you can't even open the frunk to get the tow hook unless you have a 12 volt battery sitting around to pop the frunk release relay contacts. In a Tesla, that 12 volt lead-acid battery is single-point failure.

Scott

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MYLR | Red ext | White int | 19" | 5 seats | tow | no FSD | made/delivered Oct 2021

 

[TomServo]

If the 12V battery needs to be replaced it's covered under warranty, if out of warranty the good news is it's cheap. A buddy did one 18 months ago and this was his receipt from Tesla:

I would assume it's a bit more expensive today, but still not a lot of $$$. It was done in his driveway by a Mobile Tech.

 

[e645824]

If the 12V battery needs to be replaced it's covered under warranty, if out of warranty the good news is it's cheap. A buddy did one 18 months ago and this was his receipt from Tesla:

I would assume it's a bit more expensive today, but still not a lot of $$$. It was done in his driveway by a Mobile Tech.

I agree with you IF the mobile tech will come to you and do it. I live 50 miles from the nearest Service Center. A Mobile Tech has never come to any of my neighbors -- always have to drive to the SC.

However, I repeat my previous warning: as soon as the 12V battery warning appears, get it replaced IMMEDIATELY by any means necessary. It is a single-point failure in a Tesla. If the 12V battery is dead you can't open the doors, can't open the frunk, and can't put the car in neutral. Tow trucks hate it if you can't put the car in neutral.

Scott

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MYLR | Red ext | White int | 19" | 5 seats | tow | no FSD | made/delivered Oct 2021

 

[jcanoe]

If the 12V battery fails you can jump start the Tesla vehicle. I suggest carrying a small 12V lithium battery jump starter in the Tesla vehicle, especially on trips. Store the 12V jump starter in the frunk so you can get to the jump starter by opening the front hood. There are hacks for releasing the hood. If the 12V battery is dead then a 9V battery or a 12V A23 battery (looks like a thick AA battery) can be used to release the hood latch, access the frunk and the 12V battery. You touch the 9V battery or A23 battery terminals to the wires behind the tow hook cover located in the front bumper (driver's side) to release the hood latch.

On Tesla Model Y vehicles without Bioweapon Defense Mode (BWD) that comes with HEPA cabin air filtration you just need to remove the plastic shroud close to the firewall to access the 12V battery, battery terminals. In Tesla Model Y vehicles with the BWD the HEPA filter housing needs to be removed (several screws need to be removed) to access the 12V battery. The latest Tesla Model Y vehicles with the Ryzen processor also have a 15V lithium battery module. There are jump starting terminals on this battery module in the event the Tesla vehicles needs to be jump started.

Once you get the Tesla jump started use Sentry mode or Dog mode to keep the Tesla vehicle powered on when you exit the vehicle, until you can have the 12V battery replaced.

 

[xyeahtony]

To add to what jcanoe said, if you do buy that used car, get a new 12V battery IMMEDIATELY. Even if you have to go to Walmart and buy a $90 battery yourself. It is really really dumb, but if that 12V lead-acid battery fails, it is difficult to do anything with the car. i.e. Can't open the doors. Can't put the car in neutral. And you can't even open the frunk to get the tow hook unless you have a 12 volt battery sitting around to pop the frunk release relay contacts. In a Tesla, that 12 volt lead-acid battery is single-point failure.

Scott

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MYLR | Red ext | White int | 19" | 5 seats | tow | no FSD | made/delivered Oct 2021

Since when did Walmart sell tesla 12V batteries?

does the warranty transfer when buying from a dealer though? Didn’t think it did but getting it replaced out of pocket by tesla is not too difficult

 

[ElectricAnt54]

I’m looking to purchase a used Tesla Model Y. I’m not sure things to look out for while purchasing a used model y. Any tips on this will be greatly appreciated. Also, is it concerning that the vehicle has that “Schedule service for low voltage battery”? It seems like it’s not a big deal but would love to know. Also this particular vehicle doesn’t have the OEM wheels. Can I bargain pricing for that?

What model year and trim (Long Range or Performance) of Model Y are you looking at? Even better if you know the build date as it will narrow down issues which might have been corrected, features added or even features removed.

 

[e645824]

Since when did Walmart sell tesla 12V batteries?

does the warranty transfer when buying from a dealer though? Didn’t think it did but getting it replaced out of pocket by tesla is not too difficult

The 12V lead-acid battery in a Tesla is a standard battery that you can buy anywhere. Just get the correct size with the posts in the right places. The "new" "12V" small batteries are actually lithium (~ 15V) and should last much longer than the 12V lead-acid batteries.

Scott

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MYLR | Red ext | White int | 19" | 5 seats | tow | no FSD | made/delivered Oct 2021

 

[jcanoe]

The 12V lead-acid battery in a Tesla is a standard battery that you can buy anywhere.

Actually it is not. The 12V lead acid battery used in the Tesla Model Y, until late 2021 when Tesla switched to a 15V lithium battery, is made specifically for Tesla by AtlasBX Global Battery Company Hankook. The Hankook battery is a maintenance free (MF) deep cycle flooded lead acid battery with a 40 Ah capacity. You would would have a hard time finding a suitable replacement battery except from the Tesla Service center. Tesla will sell you the 12V battery for you to install or Tesla will swap the 12V battery in your Tesla vehicle for a slight service charge.

 

[e645824]

The 12V lead-acid battery in a Tesla is a standard battery that you can buy anywhere. Just get the correct size with the posts in the right places. The "new" "12V" small batteries are actually lithium (~ 15V) and should last much longer than the 12V lead-acid batteries.

Scott

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MYLR | Red ext | White int | 19" | 5 seats | tow | no FSD | made/delivered Oct 2021

Here is the Hankook table. The Model Y uses Hankook 85B24LS and it is a Group 51 battery (JIS Group B24) maintenance free (MF) automotive battery, This exact model appears to only be available from Tesla Service Centers for $85 (if you install it yourself) or ~ $140 for them to install. There's no indication one way or the other that this is a deep cycle battery (see manual PDF link below). Its sealed lead-acid (not AGM).

USA

International

Tables curtesy of android04 from the TMC thread shown below.

Hankook manual:

https://cdn.hankook-atlasbx.com/PRD...7-4134-ba7c-a3e33e1e31ca/HANKOOK_GLOBAL_C.pdf​

So in a pinch if the Tesla Service Center is out of the 85B24LR, wouldn't someone just run to O'Reilly's and get one of these standard maintenance-free Group 51R batteries:

https://www.oreillyauto.com/detail/...ery-group-size-51r/ssbq/51rplt?q=51rplt&pos=0​

like the folks in this related thread are doing:

https://teslamotorsclub.com/tmc/thr...e-tesla-unsatisfactory-response.207179/page-7​

Yes, ideally we'd just get the correct one from a Tesla Service Center and pop it in ourselves. But if the TSC is hours away (like mine is), or too far for Tesla Mobile Service to come (like I am), or they are out-of-stock, then something quick and local is the only choice.

Scott

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MYLR | Red ext | White int | 19" | 5 seats | tow | no FSD | made/delivered Oct 2021

 

[jcanoe]

The battery in the link you provided is an AGM battery. If you install an AGM battery the vehicle's charging system may overcharge, damage the battery. The float voltage for an AGM battery is temperature sensitive and is also lower than the 13.5V to 14V float voltage of a flooded lead-acid battery. I believe the location of the battery posts on the Tesla Hankook battery are reversed.

 

[CMPT PAD]

If the 12V battery needs to be replaced it's covered under warranty, if out of warranty the good news is it's cheap. A buddy did one 18 months ago and this was his receipt from Tesla:

I would assume it's a bit more expensive today, but still not a lot of $$$. It was done in his driveway by a Mobile Tech.

I wonder if Tesla could (and technically able to) use the new lithium-ion battery in lieu of old lead-acid one ???

 

[TomServo]

And this might be useful -

 

[CMPT PAD]

And this might be useful -

Thanks Tom, so the answer is Yes. Right? My question is specifically about new Tesla 12v battery. I wonder if ít's better or worse than those from the 3rd party. Many thanks

 

[e645824]

The battery in the link you provided is an AGM battery. If you install an AGM battery the vehicle's charging system may overcharge, damage the battery. The float voltage for an AGM battery is temperature sensitive and is also lower than the 13.5V to 14V float voltage of a flooded lead-acid battery. I believe the location of the battery posts on the Tesla Hankook battery are reversed.

Correct. I should not have linked to an AGM battery since the Tesla battery module isn't expecting to see an AGM battery. The 85B24LR is not an AGM battery.

The Tesla S had an AGM battery, but the X, 3, Y had MF batteries. I think that's what confuses folks when they see a post saying, "Tesla uses an AGM battery" when what is actually meant is that the Model S used an AGM battery.

Thanks,

Scott

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MYLR | Red ext | White int | 19" | 5 seats | tow | no FSD | made/delivered Oct 2021

 

[e645824]

I wonder if Tesla could (and technically able to) use the new lithium-ion battery in lieu of old lead-acid one ???

The issue with retrofitting the new 15.5V lithium into existing Model Y is that the wiper motor would need to be replaced also. And 15.5V would be presented on the tow harness. These issues were raised in other TMC threads specifically talking about putting the new Tesla lithium battery into older vehicles. Might be why Tesla decided not to offer the retrofit service.

At this point, I think that the Ohmmu.com and the lithiummoto.com batteries claim to be drop-in replacements for the existing sealed lead acid battery.

For me, I'm getting an Ohmmu once my existing Tesla battery is 12 months old... Where I live, my batteries in my ICE cars only last 3 years at best and I got in the habit of replacing before they die. Stranded on the side of the road with a bricked car just isn't worth the alternative.

Scott

https://www.lithiummoto.com/tesla-12v-battery
https://www.ohmmu.com

--

MYLR | Red ext | White int | 19" | 5 seats | tow | no FSD | made/delivered Oct 2021

 

[jcanoe]

Are you certain? Please provide a reference.

By all accounts, the 85B24LR is not an AGM battery. The Tesla S had an AGM battery, but the X, 3, Y had MF batteries. Plus, $85 seems extremely cheap for an AGM battery. Just asking because the info on the 85B24LR from Tesla (and everywhere else) seems incomplete.

Thanks,

Scott

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MYLR | Red ext | White int | 19" | 5 seats | tow | no FSD | made/delivered Oct 2021

I meant the retail link, not the Atlas catalog battery. The Tesla 12V lead acid battery is MF but it is not an AGM battery.