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Has anyone replaced their 12V battery yet?

Garlan Garner

Banned
Mar 31, 2016
11,351
6,064
Chicagoland
Has anyone replaced their 12V battery yet?


Has anyone experienced the warning message that speaks to the battery going bad?


Should the battery be replaced every "X" number of years - no matter what?
 

mackgoo

Member
Oct 18, 2014
185
17
SoCal
Mine came in around 120000 miles. You have to replace it. If it dies the car dies. I had Tesla replace it. It was expensive as I remember 259 bucks or so.
 

EVNation

Member
Dec 20, 2019
187
107
SoCal
I've decided just to carry a mini jump pack with me so I can get home in case my 12V dies, since there's nowhere I really have to go at the moment. 2018 with 29k miles here.
 
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theeskimo

Member
Sep 26, 2019
61
64
Vancouver Washington
Mine needed to be replaced after only 3k miles. Came along with these wonderful warnings and the car not being drivable for about an hour after work one day until it “charged up” enough for me to drive away.

It was covered under warranty. I was treated very well at the SC.
 

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EnrgyNDpndnce

Member
Sep 12, 2016
629
1,025
Charleston, SC
@mackgoo do you really have over 120k miles on a Model 3? If so that Gotta be close to a record.

@Garlan Garner great topic, thanks for starting. My 3 is only a year and a half old but I’m at 78k miles and have been wondering about this myself. If I were still driving an ICE car I would replace the 12V at 100k miles even if no problems, not sure if I should do so with the 3 or wait for the warning.

And can the Model 3 be safely jumped from another vehicle? I believe I read Tesla does not recommend using Model 3 to jump start another vehicle but is the reverse true? And would it matter, as we aren’t using the 12V to “start” our cars, more to power accessories.
 

smatthew

Active Member
Jun 9, 2018
1,255
2,052
CA Bay Area
And would it matter, as we aren’t using the 12V to “start” our cars, more to power accessories.
Actually, Tesla made a design decision with the 3 that means we are using 12V to start our cars. Let me explain. Inside the battery pack is the High Voltage Controller (HVC). It is actually directly connected to the battery pack. It supplies 25V power to the High Voltage Processor (HVP) and High Voltage Battery Management System (HVBMS), and 10V power to the pyro disconnect. Those systems are what report battery capacity to the main computer, and control opening/closing the High Voltage Contactor.
The Power Conversion System (PCS) produces 12V to recharge the battery, but the PCS only works when the HV Contactor is closed.
Because the HVC is directly connected to the battery, it will continue to function without 12V power, but cannot begin operation without 12V power. So without 12V power, the car can't close the contactor to allow the PCS to make more 12V power.

I'm hoping that in the future Telsa upgrades the HVC so there is a backup way it can start operations without 12V power OR the car could be upgrade via software to enter an "OH SHOOT" mode when the 12V battery dies where the car stays on and PCS maintains a 12V output indefinitely - it would use up range, but the car would remain drivable.

Would you rather the car just refuses to work when the 12V battery dies? Or you get a message that say "12V battery dead. Increased main battery usage to compensate will result in higher standby losses. Please replace 12V battery ASAP. If main battery reaches 20% power support mode will be disabled and car will be unable to start"


PS: Yes, this means you can jump a Tesla from another car. I would do it differently than normal jumping though. Normally, when jumping an ICE, you keep the engine running in the donor car. I would turn the engine off when trying to jump a Tesla. Once the Tesla turns on, it should start trying to charge the bad 12V battery, and the Tesla should continue to run until turned off.
 

XLR82XS

D M C
Jul 26, 2019
3,126
1,761
SWFL | Vegas
Has anyone replaced their 12V battery yet?

Has anyone experienced the warning message that speaks to the battery going bad?

Should the battery be replaced every "X" number of years - no matter what?
Not yet but as a rule in Florida I like to replace every 3 years. Due to excess heat we see here 12V batteries don't last much past 3.5-4 years.

My 2016 Camry original battery lasted less than 3 years.
 

sduck

Mr. Duck
Nov 6, 2017
1,451
1,440
Nashville TN
My 12v died after about one year (last summer). First I got warning message about something wrong with the seatbelt warning system (or something similar), and then later that morning got the dreaded 12v battery low - service immediately warning. At about 2 in the afternoon I tried to drive it, it wouldn't start, although the windows and doors etc worked. Called roadside assistance, they sent a tow truck (after a bit of a wait), they managed to jump it, and I drove it to the service center, got it there right before they closed. Battery was replaced first thing the next morning, covered by warranty.

Not what one really wants to have happen, but my understanding that this was a fluke, just a bad battery. We'll see, if it happens again in the next few months I think I'll put in one of those Ohmu LI batteries.
 
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The_Observer

Member
Feb 14, 2020
707
426
Los Angeles
Kind of off topic, but jumping the 12V battery on the Tesla is no different than jumping the 12V on an ICE car, is that correct? Would any portable battery jumper would do the trick? Would jumping the 12V battery yourself void any sort of warranty?
 
Mar 25, 2018
8
17
Sarasota
Mine died at 2 years and 65,000 miles. Pulled it out myself and took it to Tesla Service center and swapped it out for a new one. I think it cost $89 or there about. Tesla was going to come to my house, tow the car to the Service Center, and let me pick it up the next day. Much faster, easier, and cheaper to pull it out myself and install the new one myself. Also only took and hour from dead car to live car instead of having to pick it up next day.
 

Dennis H

Member
Aug 29, 2019
14
8
97080
Mine died at 2 years and 65,000 miles. Pulled it out myself and took it to Tesla Service center and swapped it out for a new one. I think it cost $89 or there about. Tesla was going to come to my house, tow the car to the Service Center, and let me pick it up the next day. Much faster, easier, and cheaper to pull it out myself and install the new one myself. Also only took and hour from dead car to live car instead of having to pick it up next day.
 

Dennis H

Member
Aug 29, 2019
14
8
97080
I just had the 12 v battery in my 2015 MS P90D replaced by the Tesla mobile service unit. He came to my work and completed it in 30 minutes. It cost a total of $ 196.
The Portland Oregon Tesla Service Center is great !!!
 
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