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How do I replace the 12v battery??
- Thread starter Cooksomerice
- Start date
Lasttoy
Active Member
I was coming down 95 , all of a sudden the car quit at 80mph. NO warning. Scared me in heavy traffic, I was 2 miles from super charger in Rocky Mount. Called Tesla, 12v battery dead. ??? Huh? I bought volt meter. Battery had 12v. Finally got female on phone who knew her stuff. I needed a super jumped. Tow guy returned, jumped me to 13.5 volts. The car came alive, connected to super charger and battery went to 14.7v. Filled up car. I trailed it home just in case, I've been driving it for 2 weeks and no problems.
It's in a really hard place under the frunk cowling. Finding the right size tools is harder than charging it. I will wait till it dies before I change it.
It's in a really hard place under the frunk cowling. Finding the right size tools is harder than charging it. I will wait till it dies before I change it.
FWIW, a healthy 12V car battery will be around 12.6-12.7 volts when charged and resting and 13.5 (or more) when charging. Measuring 12.0 V on a charged battery means something is wrong. That voltage would reflect 50-60% discharged battery under normal conditions.
My car wouldn't wake up this morning, and the battery measured 11.75V - either the battery is dead or something happened to the charging circuit. Since I have the ESA, I will let Tesla figure that out... Pretty sure I still had the original battery. Car was built in Dec 2014 - 5+ years life isn't bad I guess.
My car wouldn't wake up this morning, and the battery measured 11.75V - either the battery is dead or something happened to the charging circuit. Since I have the ESA, I will let Tesla figure that out... Pretty sure I still had the original battery. Car was built in Dec 2014 - 5+ years life isn't bad I guess.
reddy
Active Member
That, Sir, may be the worlds record. I haven't had any last more than 2 years on my 2013 S.
Just peeked at the battery today. It has a date of 4/2015 which is a bit odd as my car was built in 12/2014. It must have been replaced sometime very early - maybe the first annual service? Don't know. Anyway, still got five years out of it. Seems like a decent life. Just wish I had gotten a warning before it failed.
> You will regret not buying the lithium... [Evoforce]
For the average EV a Li-Ion 12v battery certainly makes sense. However the ModelS supposedly introduces spiking voltages on top of the usual ~14.4 vdc charging current. This has been documented elsewhere but not explained. I'm awaiting delivery of an oscilloscope to show my DC-DC output waveform so will for the time being use a lead-acid replacement. Charging voltages above 15vdc can damage Li-Ion over time regardless of their particular chemistry is the usual caveat.
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Yes, my 20 month old battery recently died and for the first time I've had the opportunity to do the job myself.
Remove wiper arms: One arm could not be shaken loose with temperatures in the low 40s (F) but a few days later over 50F popped right off. Slight warming of the alum over steel would also work using heat gun.
Relocate 12v battery to Frunk: This will make disconnecting and replacing the 12v battery much easier. Disconnecting makes sense now that the car is not being used due to Covid19 pandemic and other reasons. My WAG is that ModelS that are 'driven daily' manage to get long service life out of the lead-acid so I plan to disconnect mine for weeks or months at a time. Also hope find a convenient tap to monitor the hv so as to avoid the rebooting just to check the main battery.
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For the average EV a Li-Ion 12v battery certainly makes sense. However the ModelS supposedly introduces spiking voltages on top of the usual ~14.4 vdc charging current. This has been documented elsewhere but not explained. I'm awaiting delivery of an oscilloscope to show my DC-DC output waveform so will for the time being use a lead-acid replacement. Charging voltages above 15vdc can damage Li-Ion over time regardless of their particular chemistry is the usual caveat.
---
Yes, my 20 month old battery recently died and for the first time I've had the opportunity to do the job myself.
Remove wiper arms: One arm could not be shaken loose with temperatures in the low 40s (F) but a few days later over 50F popped right off. Slight warming of the alum over steel would also work using heat gun.
Relocate 12v battery to Frunk: This will make disconnecting and replacing the 12v battery much easier. Disconnecting makes sense now that the car is not being used due to Covid19 pandemic and other reasons. My WAG is that ModelS that are 'driven daily' manage to get long service life out of the lead-acid so I plan to disconnect mine for weeks or months at a time. Also hope find a convenient tap to monitor the hv so as to avoid the rebooting just to check the main battery.
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