12v Battery Low - Car Needs Start - Pull over immediately

TechGuy · Feb 18, 2015

Guess how my day is going?

I'm at a coffee shop -- happily, with WiFi -- and waiting for a tow. Tesla says they'll be here in 2-3 hours. I'm planning a road trip from Pennsylvania to Denver next month. I'm thankful that this failure occurred while I was alone rather than with my wife and 4 year old!

- - - Updated - - -

Typo in the title - "Car Unable to Start" I think was the message. Doesn't look like I can edit titles, though. Oh well.

AndY1 · Feb 18, 2015

I guess a Model S should have a mandatory spare 12V battery, like cars have spare light bulbs :biggrin:

TechGuy · Feb 18, 2015

I had heard of others getting the 12v error... has Tesla not yet figured out a solution?

iadbound · Feb 18, 2015

I got it recently. It wasn't the 12V in the end. The 12V failed because the power switch for the main battery failed, which kept the 12v from charging properly (I think -- not an expert). I gather there is more than one thing that can cause this, but plainly Tesla hasn't gotten them all sorted out yet.

steve841 · Feb 18, 2015

{broken record} ... so sad the achilles heel of the Model S is a freakin stone age 12V battery.

Vger · Feb 18, 2015

steve841 said:
{broken record} ... so sad the achilles heel of the Model S is a freakin stone age 12V battery.

As indicated above, this does not necessarily mean that the 12V battery is the cause, just the symptom. Anything that prevents power getting from the main battery, through the DC-DC convertor, to the 12V circuits can cause this. The 12V battery runs out of charge very quickly if the full 12V draw is on it, and it is not being re-charged from the HV battery.

caddieo · Feb 18, 2015

How old is the car? There is another thread re: the 12 volt battery regarding proactive yearly replacement instead of waiting for failure. Apparently, as with other deep cycle batteries, the ability to recharge unavoidably diminishes with age.

TechGuy · Feb 18, 2015

Mid-2014 with around 12,000 miles on it.

ThosEM · Feb 18, 2015

I gather it is more typical for a warning to come up that the battery needs service. When I called I learned that it was not an emergency and we could schedule a replacement within a couple of weeks. When I went in for that service, the adviser explained that they were concerned the warning was coming up earlier than necessary. Sounds like they fixed that and now one doesn't get a warning at all? :=\

loco · Feb 18, 2015

I had the same. Followed by main battery contactor failure few weeks later. Not sure if it's related.

TechGuy · Feb 18, 2015

loco said:
I had the same. Followed by main battery contactor failure few weeks later. Not sure if it's related.

Ahahaha... just what I need for my trip across the county!

iadbound · Feb 18, 2015

I'll be interested to see what your diagnoses is. Good luck.

TechGuy · Feb 18, 2015

Tesla just called me back... tow truck is running later than expected... looks like a total of 3 hours waiting.

apacheguy · Feb 18, 2015

Jeez, 3 hours for a tow? Seems excessive. Can't they contract the job out to AAA?

scottm · Feb 18, 2015

Measure the voltage on the battery in the meantime.

TechGuy · Feb 18, 2015

Didn't measure the voltage - where would one do that? I did have a multimeter with me. Ended up waiting 5 hours for the tow, but that included bringing a P85+ as a loaner. I'm about 80 miles from the Rockville, MD service center.

jerry33 · Feb 18, 2015

TechGuy said:
Didn't measure the voltage - where would one do that?

The easiest way is to get one of those power metres that plugs into the power port by the USB ports.

TechGuy · Feb 18, 2015

Call me a Bjorn want-to-be... but I've made about half a dozen videos about my short experience with my Tesla thus far. I managed to create another short one today, of which my son is the highlight. He was rather worried about the Tesla.

Tesla Model S - 12v Battery Failure - YouTube

breser · Feb 18, 2015

apacheguy said:
Jeez, 3 hours for a tow? Seems excessive. Can't they contract the job out to AAA?

I've waited that long for AAA before. AAA contracts out to local tow companies. You're just at the mercy of how busy they are and how far away they are.

ModelX · Feb 18, 2015

Cute!

12v Battery Low - Car Needs Start - Pull over immediately

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