It depends; a lot of people have had the car go dead in the night and need a jump. I think Tesla recently patched the software to just not sleep when that alert is set, so you'll just end up losing a lot of range every day if you don't.
It's only $100 from Tesla service. Part # 129182-00-B On Mon, Jul 28, 2025 at 9:38 PM Cor van de Water via EV <[email protected]> wrote: > Note that you absolutely do not need to hurry to replace the aux battery, > the only thing "wrong" with it is that the Tesla needs to wake up its DC/DC > converter more often than the software programmed minimum time, indicating > that capacity is below desired limit. > I got rid of the warning by swapping the battery, then used the old battery > in another of my EVs that does not complain about capacity. > YMMV. > Cor. > > On Mon, Jul 28, 2025, 8:15 PM (-Phil-) via EV <[email protected]> wrote: > > > VCFRONT in the Tesla monitors the amp-hour capacity of the lead-acid > > battery. When it drops too low, you get that alert. > > > > To change it, disconnect the negative terminal, then go into service mode > > and stop 12v support. If you don't do this the alert will stay until you > > do. > > > > On Mon, Jul 28, 2025 at 7:21 PM Jay Summet via EV <[email protected]> > > wrote: > > > > > I would not be surprised if it is almost dead. 5 years appears to be > > > about the standard runtime for most car accessory batteries. [I've had > > > the one in my Leaf and a Nissan Altima both die around that > timeframe..] > > > > > > > > > I don't know if the Tesla system is doing a calendar reminder, or if > > > they are doing diagnostics based upon the battery voltage and capacity. > > > > > > Jay > > > > > > On 7/28/25 21:27, Mark Hanson via EV wrote: > > > > Hi Folks, > > > > > > > > I got an alert on my 2021 Tesla-Y app to change the 12V aux lead > > battery > > > > after about 4.5 years 126K miles of operation. > > > > > > > > It looks like I need to go into the menu>service>PowerOff selection > > > before > > > > just plucking out the battery. > > > > > > > > In the 2013 Leaf I just changed the 12V battery without fanfare. > Also > > in > > > > the 2020 Bolt after 5 years of operation. > > > > > > > > Is 5 years the recommended aux 12V change interval? - or should I do > a > > > load > > > > test first before just changing it at a fixed time/mileage interval? > > > > > > > > > > > > Have a renewable energy day, > > > > > > > > Mark > > > > > > > > Mark E. Hanson > > > > 184 Vista Lane > > > > Fincastle, VA 24090 > > > > 540-473-1248 phone & FAX, 540-816-0812 cell > > > > REEVA: community service RE & EV project club > > > > Website: www.REEVAdiy.org (See Project Gallery) > > > > UL Certified PV Installer > > > > My RE&EV Circuits: www.EVDL.org/lib/mh > > > > REEVA Demo: http://youtu.be/4kqWn2H-rA0 > > > > Fincastle Solar Weather Station > > > > > > > > > > > > > > > > _______________________________________________ > > > > Address messages to [email protected] > > > > No other addresses in TO and CC fields > > > > HELP: http://www.evdl.org/help/ > > > > > > > > > > _______________________________________________ > > > Address messages to [email protected] > > > No other addresses in TO and CC fields > > > HELP: http://www.evdl.org/help/ > > > > > > > > -------------- next part -------------- > > An HTML attachment was scrubbed... > > URL: < > > > http://lists.evdl.org/private.cgi/ev-evdl.org/attachments/20250728/73470a29/attachment.htm > > > > > _______________________________________________ > > Address messages to [email protected] > > No other addresses in TO and CC fields > > HELP: http://www.evdl.org/help/ > > > > > -------------- next part -------------- > An HTML attachment was scrubbed... > URL: < > http://lists.evdl.org/private.cgi/ev-evdl.org/attachments/20250728/3cb3e7b0/attachment.htm > > > _______________________________________________ > Address messages to [email protected] > No other addresses in TO and CC fields > HELP: http://www.evdl.org/help/ > > -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.evdl.org/private.cgi/ev-evdl.org/attachments/20250728/fe82e888/attachment.htm> _______________________________________________ Address messages to [email protected] No other addresses in TO and CC fields HELP: http://www.evdl.org/help/
