12V Battery

12V Battery

My 2010 Roadster's door unlock is not working again, and it appears to be the 12V battery according to an error message when I try to us the door handle to open the door. When this happened last time, the Ranger came out and I watched him take off the front left wheel(I think) and replace a 12V motorcycle style battery in a compartment from the wheel well.

Anyone done this? Can confirm the battery location?



cgloewen | 15 August 2013

Correction, the 12V battery is in the right front fender. Removed the wheel, removed a bunch of screws and plastic parts in the fender, replaced the motorcycle battery with one from AutoZone, and back on the road.


Brian H | 15 August 2013

Zoom, zoom!

Scott M | 5 October 2013

Got an error message that the 12V battery had failed. Took it in and Tesla replaced it under warranty. I didn't even know it had a 12V battery. I thought it had a transformer that converted 400V to 12V for the accessories.

markwj | 9 October 2013

Scott M: 12V battery is primarily for emergency systems. If the main traction battery fails, the little 12V lead acid one will provide power for things like emergency signal flashers, brake lights, etc.

Brian H | 10 October 2013

The 12V battery is in use all the time, runs all the displays and small motors, etc. It is topped up as needed from the main battery by a DC-DC connection.

ColonyGolfer | 10 October 2013

Tesla called me to tell me they were coming out to replace the 12v battery in my Model S Sig at about 1200 miles a few months back. Their monitoring system told them it was operating outside their parameters. They had to remove the wipers, and the plastic panel below the wipers. Then unscrew the fusebox and tie it up, out of the way. Then they could get at the battery. Took about an hour.
I later learned that their supplier of these batteries had subbed the work out to a Vietnamese company who did substandard work. A very inconvenient place for a battery.

Brian H | 5 December 2013

↑Stupid Russian SPAM. Teslas have no use for alternators.

allen.riddoch01 | 9 December 2013

I had similar problem few weekd back, but I got it replaced.

scotty2541 | 24 January 2015


Was this all it took? Was there a need to reset any settings?
Because I was told the system counts the battery cycles and needs to be told the battery was replaced. Kind of like an ICE telling you it's time for an oil change.

Because I'm ready to do it myself.


guysun67 | 27 January 2015

telling you it's time for an oil change.

Fifa coins

scotty2541 | 17 September 2015

I did it myself. Take a look at this.

Now if only they would select components that didn't have a 15 month life span... Seriously.