21 Model Y 12 volt Battery Quits

[davidmoa]

My 21 model Y long range was parked in my garage yesterday, 130 miles of charge 69k miles. I got in, and no display, lights, nada. Can’t open the door so I used the manual lever to get out. The app tells me to replace the 12 volt battery ‘soon’ - but the car is dead, no warnings. Now waiting till Monday for service to replace it.
I am very glad the car was in the garage when this happened. Hope Tesla figures out how to provide some warning of this failure BEFORE it happens.

 

[Hurricane4911]

I hear you, here is what I did...
I purchased a $12 voltage meter from Amazon that plugs into our cigarette/reefer lighter located in the center console.

Easy-peasy until Tesla decides to grant us a software upgrade to display 12 volt battery status.

 

[bruce4000]

So at what voltage should you be concerned / replace the battery?

 

[QtownTaxiGreg]

I hear you, here is what I did...
I purchased a $12 voltage meter from Amazon that plugs into our cigarette/reefer lighter located in the center console.

Easy-peasy until Tesla decides to grant us a software upgrade to display 12 volt battery status.

I got told the accessory power comes direct from the big battery converter, not via the "12" volt, so that wouldn't do you much good?

 

[DownshiftDre]

Service mode has LV battery health. But agree have two family members who have 12V battery issue with no warning. They have the NiCadbattery instead of the 16v lithium ion, so seems life is just short on those NiCads.

 

[E90alex]

There’s really no good way to give an accurate measurement of lead acid battery health because there’s no sophisticated BMS or electronics in the battery. You can vaguely get an idea about health with voltage but they usually fail without warning. Especially since you don’t have the major power draw of a starter like an ICE vehicle to help identify a weakening battery earlier.

 

[DownshiftDre]

Service mode has LV battery health. But agree have two family members who have 12V battery issue with no warning. They have the NiCadbattery instead of the 16v lithium ion, so seems life is just short on those NiCads.

Edit: Lead acid and not NiCad

 

[Hurricane4911]

I got told the accessory power comes direct from the big battery converter, not via the "12" volt, so that wouldn't do you

I got told the accessory power comes direct from the big battery converter, not via the "12" volt, so that wouldn't do you much good?

I "assumed" accesory power was sourced through the 12v system.

I stand corrected...from Tesloid, in 2023

NOTE: Power for the socket is only available when the vehicle is considered awake. Your Tesla will be awake when using features like Preconditioning, Cabin Overheat Protection, Dog Mode, Camp Mode, Sentry Mode, and more.

So, my happy voltage display will always read 12.7v.

 

[GtiMart]

My car started giving a few weird errors about low voltage on some controler. Service mode said my 12V was healthy but I replaced it anyway at that point. I am not getting the low voltage errors anymore. I did not get the official warning to replace the 12V.
Mine is a 2020 and I live in a place where there's serious winter. Even in ICE cars 5 years is the moment to replace a 12V around here. My car had seen 5 winters so I was about to change it anyway.
Remember how long your 12V lasted in your previous ICE cars and preemptively change at the same intervals. I presume high temperatures are also hard on that 12V.

 

[leenanj]

I wish there was a 12v lithium option for my 21 model Y.

 

[Vicj]

Elon is a strange dude. He won't produce a 12v lithium for older cars yet actively sabotages the batteries from companies that would produce them for us, like Ommu.

 

[QtownTaxiGreg]

actively sabotages the batteries

How does the car sabotage batteries?

My understanding is they are only lightly loaded by essential systems. They are topped up once any drain is recognized. All the accessory power comes direct from the big battery.

Afaik the only time they get drained is when someone runs the big battery right down and it stops giving to the little one. That or it dies of "old age" and won't take a charge.

 

[Pianewman]

My car started giving a few weird errors about low voltage on some controler. Service mode said my 12V was healthy but I replaced it anyway at that point. I am not getting the low voltage errors anymore. I did not get the official warning to replace the 12V.
Mine is a 2020 and I live in a place where there's serious winter. Even in ICE cars 5 years is the moment to replace a 12V around here. My car had seen 5 winters so I was about to change it anyway.
Remember how long your 12V lasted in your previous ICE cars and preemptively change at the same intervals. I presume high temperatures are also hard on that 12V.

Yes, high temperatures are harder on an ICE 12V battery than low temps. Both extremes take their toll.

Living in high-heat Texas (DFW region) I will continue to replace lead-acid battery in my Tesla every 2.5-3 years. I won't wait for a failure.

That said, the 12V batteries in my Toyota hybrids (Avalon and Prius) last much longer, 5-6 year. It's a much more robust (and expensive!) battery, gel/sealed 12V.

 

[Vicj]

How does the car sabotage batteries?

My understanding is they are only lightly loaded by essential systems. They are topped up once any drain is recognized. All the accessory power comes direct from the big battery.

Afaik the only time they get drained is when someone runs the big battery right down and it stops giving to the little one. That or it dies of "old age" and won't take a charge.

Just go to the Ohmu site you can read up on how Tesla actively programs the BMS to reject other LiOn 12 volt batteries. Pretty common knowledge.

 

[jjrandorin]

Just go to the Ohmu site you can read up on how Tesla actively programs the BMS to reject other LiOn 12 volt batteries. Pretty common knowledge.

Or, one could look at threads / video about the ohmmu battery here, like this one:

12V and 16V battery video by Ingineerix - Ohmmu Issue explained

New video by Phil: Lead Acid 12V vs 15.5V by CATL. Ohmmu disaster explained. Just don't buy this time bomb.

teslamotorsclub.com

 

[QtownTaxiGreg]

Can't watch vids at work. What's the guts?

 

[QtownTaxiGreg]

I wouldn't put a 16V lithium in a 12v car any more than put my cat up at the dog kennels.

 

[Vicj]

Of course not. They make 12volt lithium batteries for Teslas