Welcome to Tesla Motors Club
Discuss Tesla's Model S, Model 3, Model X, Model Y, Cybertruck, Roadster and More.
Register

Near annual replacement of 12V battery is typical according to Tesla Service Tech

This site may earn commission on affiliate links.
I am at 23.6K miles and 19 months, with no indication from Tesla or the car that my battery needs replacement. Did they start installing better 12v batteries or link them to a generator later in the production cycle?

I just had my car in for service after 30 months. I never saw a notice about the 12V system, but my service advisor said they had been getting notices about the 12V system for a while. If I were you I would check with your service center and see if they are getting any notifications. If so, schedule a service visit for the battery to be replaced.

My Model S will be three years old next week. I have about 24,500 miles. To my knowledge my 12 v battery was only replaced once proactively by the service center a few months after it was delivered. I have never received a warning message regarding my 12 v battery in those three years.

A couple of weeks ago I noticed that a coolant pump seemed to be running almost constantly. I also noticed that my vampire drain was over 15 miles per day even with my car set to Energy Savings ON, Always Connected. This situation persisted for a week until the service center could schedule my car for a visit. (The problem turned out to be a fault in the electronics associated with the drive unit pump along with a refrigerant leak.)

With the exception of the early battery replacement I have never seen another battery replacement noted on any of my service tickets, including this last visit when the battery was subjected to more than three times the typical vampire load.

Now that I have mentioned my good fortune, no doubt I have jinxed myself. :wink:

Since I'm coming up on 25,000 miles I plan to take the car in for annual maintenance in a few weeks. I'll make a point of checking with the service center to ensure they check the records on my 12 v battery replacement and replace the battery if warranted.

Larry
 
My Model S will be three years old next week. I have about 24,500 miles. To my knowledge my 12 v battery was only replaced once proactively by the service center a few months after it was delivered. I have never received a warning message regarding my 12 v battery in those three years.
I had one battery replacement at about two years, and a second one a month later (obviously a defective battery), no replacements since at 62K miles. Assuming that two years is normal for me, next one should be in 2017. The warning came up each time so there was no driving time lost. This beats the VW TDI which required a new 12V battery ($189 + tax each) and a tow every year (because you can't jump a shorted out battery).
 
FLAT:
You are on to something with the environmental observation....
The effects of ambient temperatures on auto batteries is very important. Perhaps even more so with the Tesla.
Here in CT, my car is stored in an enclosed, none attached, unheated garage. In February when we have prolonged very cold sub 30 F weather is typically when
battery starting issues in ICE cars begin.

Also, does not the Model S battery system try to keep the traction battery at a certain minimum temperature? Does this power come from/thru the 12V battery
regardless of the S being plugged in or not?

Here in CT I have four cars now, One with a 9 year old battery (Optima) on trickle charge, One with a 4 year+ battery Volvo, One with a 2+ year old battery Prius and
the AMX has a 6 month old battery.... The previous one died this summer on a very hot spell (It was also trickle charged 100% of the time) and was 5 years old when it died.

I suspect the Optima will be the next to go or the Volvo Battery.
 
Also, does not the Model S battery system try to keep the traction battery at a certain minimum temperature? Does this power come from/thru the 12V battery regardless of the S being plugged in or not?

No. The car wakes up and the power comes from the traction battery. The 12V wouldn't even begin to keep the batteries warm.

Also Optima today isn't the Optima of ten years ago. The company has been sold and the batteries are now produced in Mexico with the expected results.
 
That has not been my experience in any modern vehicle, 2 years seems much more normal.
Maybe because you are sub-zero in Calgary ... 5-6 years is the norm in California. :cool:

My Toyota 4Runner went 7 years before it needing to be proactively replaced because the cold cranking amps were getting low and there was q concern that when winter hit, I could have a problem.
 
The anecdotal experience of 12V battery life experienced with ICE vehicles, while mildly interesting from an expectations perspective, is irrelevant given how different the demands placed on the battery are compared to an EV. Data on 12V battery life in other EV's, especially the Leaf, and even those (i3, Volt) with range extender engines when driven mostly in EV mode, would be interesting.

The observed battery life in Model S seems consistent with the high vampire loads (even with the improvements from the early days) that deep cycle the battery on approximately a daily basis. Perhaps some of the load is justifiable for battery management, but overall it does seem like the vampire load is due to having a lot of processors that remain active rather than going into a low power sleep state. Perhaps this is a design error or perhaps some of this was a deliberate engineering trade-off to enable the "instant" get in and drive that is part of the Tesla experience, but it does come at the price of wear on the 12 V battery. The delay starting up an ICE also provides time for starting up a lot of secondary processors. (Of course, hybrids are in principle driveable on the battery before the ICE is started but the start up expectation is still that of a standard ICE.)
 
  • Informative
Reactions: ferdboyce
The anecdotal experience of 12V battery life experienced with ICE vehicles, while mildly interesting from an expectations perspective, is irrelevant given how different the demands placed on the battery are compared to an EV. Data on 12V battery life in other EV's, especially the Leaf, and even those (i3, Volt) with range extender engines when driven mostly in EV mode, would be interesting.
Volt had problems with the battery in the initial model year - it could be charged only while the car is "on". It was fixed pretty quickly.

Now Volt has no problems at all with 12V, it's as reliable as it can get. The load placed on it is really low - the main battery pack is used to start the ICE, so deep cycling is a non-issue. As for "instant driving experience" - Volt is on par with Tesla. You simply sit, press the "power on" button, shift into gear and start driving. You can do it all within one second.

Volt's infotaiment system does take some time to start up, though. Tesla has some advantage here.
 
Starting a motor is not "deep cycling", it's a short high power event, and the battery is charged quickly as soon as the motor is started. Deep cycling means long term draw down of the battery capacity to a low state of charge.
Yes, you're correct. I have just checked the standby power use on my Volt with a watt-meter, it's just 2W after the car is idle for more than 15 minutes.