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12 Volt Battery Replacement

Beryl

Supporting Member
Supporting Member
Feb 19, 2015
681
234
South of Houston
I sent the following email to Tesla Service:

Tesla Service ,
I had my 12v battery replaced one day after the first warning message appeared. Replacement resolved three issues that I’ve been working around for a very long time lessening my enjoyment of my vehicle:

  1. The button on my High Power Wall Charger nozzle would not open the charging port. I had to press the left side of the port to get it open.
  2. My car wouldn’t recognize key fobs until I took them out and either put it in the cup holder or press buttons on the fob a few times. This made managing the doors, frunk, and trunk difficult. I used to be able to leave my fob in a pocket or in my purse and it would be recognized. I told the service center that I suspected the fob issue was related to the 12V. After the battery was replaced, they noticed that the fob problem (which they also observed) was gone.
  3. My phone's Bluetooth connection is finally working consistently in my garage. My garage was the only place it would have a problem. I complained to Tesla months ago but they had no resolution. I tried many things — toggling WiFi, adding a repeater — to no avail. I needed to exit my garage before using my phone. Now I can finish phone calls and listen to tunes on my phone when I arrive home in my car.
Moral:
If a customer complains about issues that you are unable to resolve, try replacing the 12 volt battery.


Note that I had received my 2nd year service 2 weeks before the failed battery message appeared. The problems reported had been going on from weeks (key fob) to a year (Bluetooth). I just lived with them. I am posting to illustrate that problems that may seem to be unrelated to the 12 volt battery may be resolved by replacing it.
 

Haxster

Member
Apr 4, 2016
859
1,397
Silicon Valley
I wonder if a cell in your old 12V battery was shorted (1 cell of 6). This could explain the issues that you were having. An easy test is to just plug in a voltmeter or voltage monitor into the 12V accessory socket. Normal voltage should swing between about 12.5 and 14.5. A shorted cell will knock it down a couple of volts.

I'm not sure exactly what triggers the failed battery message, but, if my analysis is correct, a simple voltage check at the service center should have found the source of your problems.
 

scottm

Legacy account
Jun 13, 2014
3,070
2,346
Canada
Strange that all the RF interference was happening in your garage... I would suspect something changed there at the home that brought this on, and coincidentally a 12v battery service happened with something else in yhe garage / home also changing again.

Alarm system, wifi repeater, new cordless phone... anything else in the garage / home change recently, or temporarily?
 

Beryl

Supporting Member
Supporting Member
Feb 19, 2015
681
234
South of Houston
Strange that all the RF interference was happening in your garage... I would suspect something changed there at the home that brought this on, and coincidentally a 12v battery service happened with something else in yhe garage / home also changing again.

Alarm system, wifi repeater, new cordless phone... anything else in the garage / home change recently, or temporarily?
No other changes at the home by me. The problem started a year after getting the vehicle so I looked at changes at that time.

I agree though that it doesn’t seem as likely as the others. I do wonder if the recent xfinity speed boost might be related.
 

Xenoilphobe

Active Member
Jan 2, 2014
4,600
4,522
Fairfax County, Virginia
I'm not sure, I didn't put the stock lead-acid battery back in, I went aftermarket with a more powerful Lithium battery - ~$440 for the LiPo battery with these specs:
  • Direct fitment in Tesla Model S and Tesla Model X vehicles
  • Cycle life 3x higher than OEM battery
  • 35% of the weight of OEM battery (increase efficiency, 9.5lbs vs. stock @ 27lbs)
  • Decreased life-cycle cost! Per cycle ~$0.18 VS OEM battery ~$0.25
  • Get the lead out of your advanced vehicle; an advanced technology vehicle calls for an advanced technology battery!
  • Flame retardant ABS plastic case
  • Shock-proof construction
  • Safe Lithium Iron Phosphate chemistry, will not explode if over-charged or subjected to damages!
  • Dimensions: 195mm x 130mm x 158mm (7.7" x 5.1" x 6.2")
  • Peak discharge: 210A (CCA)
  • Continuous charge/discharge: 60A
  • IP67 rated for water and dust resistance
 
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Xenoilphobe

Active Member
Jan 2, 2014
4,600
4,522
Fairfax County, Virginia
Strange that all the RF interference was happening in your garage... I would suspect something changed there at the home that brought this on, and coincidentally a 12v battery service happened with something else in yhe garage / home also changing again.

Alarm system, wifi repeater, new cordless phone... anything else in the garage / home change recently, or temporarily?

My LED lights affect the Homelink range, when they are on, range is limited, when off range is fine.
 
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Reactions: ohmman

scottm

Legacy account
Jun 13, 2014
3,070
2,346
Canada
Keep in mind if swapping batteries, Tesla has at least a couple different generations of 12v batteries now and needs to change parameters in the car settings as to which type is installed. Probably changes the way the 12v charging happens depending on battery characteristics.

So maybe inquire if you're dropping some non Tesla battery into the car, or doing the change out yourself and notice that it's not an identical part number going back in.
 

MSullivan

Member
Apr 6, 2016
214
156
New England
My 18 month old refreshed 75D gave me a 12v battery error message. It was replaced for free under warranty by a "ranger" who came to my home for a previously scheduled console problem. Timing worked out great.
He said I had the old generation battery and my new one is the newer version. As mentioned above he had to "tell" the car it had a different battery. I was pretty amazed that was a necessary step.
 

gregd

Active Member
Dec 31, 2014
2,587
1,802
CM98
My bet is that the replacement of the battery necessarily resulted in a power cycle of the car, and reset some component that was actually the root of your earlier troubles. A full-car reboot might have cleared them, too.
 

bradc

Member
May 16, 2013
43
6
Seattle, WA
What's the cost of the 12v outside of warranty? Is the 12v even covered by warranty?

Recently got a 12V battery warning on my 2013 Model S. My understanding is that this replacement is complimentary during the warranty period. As my car is out of warranty, I was charged for the replacement. With tax I was out the door for under $200.

tesla12v.PNG
 

beeeerock

Active Member
Mar 12, 2015
1,514
434
Kamloops BC Canada
I got the message that my battery should be checked out in the next while... service center suggested the new ranger service could fix it in March...(!)

Wondering if there is any consensus on how long between first appearance of the message and a failure? I don't particularly want to get stuck. I don't particularly want to look at the message that won't clear either, but I can probably suffer through that... ;-)
 

alloverx

Member
Mar 20, 2016
900
757
Seattle
My 18 month old refreshed 75D gave me a 12v battery error message. It was replaced for free under warranty by a "ranger" who came to my home for a previously scheduled console problem. Timing worked out great.
He said I had the old generation battery and my new one is the newer version. As mentioned above he had to "tell" the car it had a different battery. I was pretty amazed that was a necessary step.

I recall some old BMW 5 series had the same setup. You had to tell them what kind of battery was installed.
 

Evoforce

Active Member
Apr 19, 2017
1,550
1,913
Fountain Hills AZ
Where I am, winter temperatures would likely kill an unmanaged lithium battery. I don't think it's a one-size-fits-all solution!

This battery isn't unmanaged. Being that I am also from Michigan as well as AZ, I have never had problems with this battery in freezing cold temperatures. It is also backed up by your traction battery, and as you probably know, you don't need high cranking amps like on an ICE vehicle.
 
Last edited:
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Cosmacelf

Well-Known Member
Mar 6, 2013
8,777
22,250
San Diego
This battery isn't unmanaged. Being that I am also from Michigan as well as AZ, I have never had problems with this battery in freezing cold temperatures. It is also backed up by your traction battery, and as you probably know, you don't need high cranking amps like on an ICE vehicle.

It is unmanaged as far as keeping it warm or cold is concerned.
 

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