12V battery

12V battery

Don't know if this has been discussed before. Where is the 12V battery located and how can it be accessed? And why it needs a 12V battery since the car has no engine. Can we change it like a regular car battery if it fails? Or it must go back to service and pay an arm and a leg for a 12V.

NumberOne | January 21, 2016

The Jump location is indicated in the towing manual. The 12v battery itself is used for controlling the accessories. The main battery pack is for the drive train

Roamer@AZ USA | January 21, 2016

It is not a traditional automotive lead acid battery. The battery used is is a sealed battery similar to what is used in backup power supplies and mobility scooters.

I have owned three model S cars and experienced several 12 volt failures in the early days of the S. I have never paid for a battery or battery replacement. All done at no charge by Tesla.

Since everything in the automobile world is 12 volt many of the the things needed to operate a car are mass produced in 12 volt. Drive motors, radio devices, lights and on and on. It would be incredibly expensive to redesign and produce in small quantity all these items. Not to mention that the main batteries operate at significantly higher voltage and amperage than you would want running all over your car.

The 12 volt wakes up the cars and powers things up then the 12 volt system are powered by a DC to DC converter that taps into the main battery system and produces the 12 volt needed to operate all the items in the car.

The 12 volt battery is a deep cycle type designed more for steady moderate power loads. Nothing like the lead acid start battery in an ICE. In an ICE battery what you need are cold cranking amps. The battery is designed to produce max power for a short time to drive a starter motor and start and engine. In a Tesla the deep cycle battery unlocks a door and activates a DC to DC converter. Different needs and different batteries for different reasons.

tonyx | January 21, 2016

@Roamer Flagged for excessive thoroughness, relevancy and appropriateness.

ian | January 21, 2016

@tonyx - Roamer's kinda annoying like that isn't he? ;-)

ir | January 21, 2016

The 12V battery is also part of the battery cutoff safety mechanism. It powers the contactors that engage the main 400V battery. Much safer for first responders to clip a 12V wire than a 400V cable to guarantee it stays disconnected.

jjs | January 21, 2016

+1 tonyx Made me laugh.

+1 Roamer - Nice post.

sp_tesla | January 21, 2016

@ir | JANUARY 21, 2016

Good to know, thanks for educating/sharing the 12V safety purpose information.

NumberOne | January 21, 2016

+10 @Roamer That was much more informative that what I said. Great post.

Roamer@AZ USA | January 22, 2016

@LeonardD, When I read my posts after I thought, Gee Leonard said the same thing I did in one sentence. I am working on learning brevity.

Brian Vicars | January 22, 2016

Tesla X 12V battery is manufactured by C&D Technologies. It is a deep cycle 33amp hour. AGM and can be installed upside down if necessary. Currently priced on Amazon for $200.

Tâm | January 22, 2016


Would you please provide the Amazon link for C&D Technologies 12V 33A AGM battery?

The search yields this which I am not sure the correct one:

Brian Vicars | January 23, 2016

@Tam. Once again, I must admit to not being very tech savy. Try c&d technologies DCS. Tesla battery is DCS-33HIT.

rossRallen | January 24, 2016

@Roamer: thanks for an informative post.

The 12V battery is located left of centerline (looking into the Frunk) behind the plastic access panel.

Red Sage ca us | January 25, 2016

Wow. Just glanced at 'DCS-33HIT' and for a split second...? I thought it was Elite Speak for 'DA $#!+'...

rossRallen | January 25, 2016

Oops! Battery is right of center looking into the trunk. I'm a little dyslexic—I once thought left and right had something to do with West and East.

Roamer@AZ USA | January 26, 2016

@ross, Just to make it worse for you. In car talk locations are always given based on sitting in the drivers seat.

But you were careful to say, as you faced the frunk, so not following normal protocol was explained.

But now I am really confused.

rossRallen | January 26, 2016

@Roamer - welcome to my world. And I meant "frunk" not "trunk" in the last post.
The battery is on the East side of the car looking into the thingy in front.