Finally discovered something that Tesla Model S cannot do. Jumpstart another car

My daughter's needed a jumpstart and my wife took the jumper cables from her and tried to put them in the Tesla so I could go. We both laughed at the same time.

Ironic, isn't it? That a car with that much electrical potential can't jump start such a relatively small thing as an ICE battery :)

Doesn't Model S has a 12v battery? not accessible to connect jumper cables?

there is a 12v battery. no idea where it is.

Perhaps Tesla could design a modified jumper cable that would plug into the wall adapter end of our charging cable and the other end into the charge port. This would only work if power could then be pulled from our batteries through this modified cable to start someones car. A software option that we would select for this may have to be added if this would even be possible. It would make it fairly easier for us to then given someone a jump vs trying to find and hookup the 12v battery we also have. It is ironic that we cannot offer a jump now. Tesla may address this as time allows in the future.

There's a private thread on how to steal your perfectly good Model S with its perfectly good 12 V battery. That's not the header but that's the discussion.

If you read it, instead of stealing it, you can EASILY access its 12 V positive post (clip negative clamp on chassis.) The instructions & pictures are quite clear and vivid.

However, your Tesla is too expensive so I wouldn't advise to mess around with it. It's cheaper to fry your portable $50 Jump Starter than your Tesla :)

The TM 12V is small, like a motorcycle battery.

The 12v battery is on the right side of the frunk near what would be the conventional firewall location. But it is not designed to be user-accessible.

You can see Tesla Model S left Red Positive and right Bare Negative lugs are VERY much easily accessible.

It probably not designed to jumpstart a car! :) Normal car batteries are bigger because of all the amps needed to crank the engine initially...

Curious why they even put a battery in there when a DC-to-DC would be sufficient to supply current to the various 12V electronics and ventilation.


If you only rely on 1 single power source from the propulsion battery, then when you broder it down, there is no way to power up that power source to get it recharged!

It is good to have separate power systems in case something goes wrong like a driver who refuses to plug in and tries to broder it down.

A Tesla Ranger can show up to the rescue and can easily wake up the the car's control systems with the 12 V and thus allow to plug in to recharge the propulsion battery.

This is not a new concept. It has been proven since the defunct GM EV1 days.

The Model S battery is 35Ah, so almost a full 'normal' car battery; not a motorcycle battery.

I'm not sure this would work, but..... I have a jumper cable that attaches from cigarette lighter to cigarette lighter. It was supposed to eliminate the necessity of getting dirty or worse from attaching jumpers directly to the battery. The downside was that it had to be left in the socket for 15 minutes. It was so useful that I can't find it now, don't remember if I threw it out, have no recollection of it ever starting any car and have a general feel that it was a waste of money. That being said, I think they're still being sold and they must work on something. Come to think of it, I've bought a lot of stuff that didn't exactly live up to my expectations. That feeling has been completely reversed by Tesla.

@info - you can't get much current out of a cigarette lighter without blowing the fuse, certainly not enough to power the starter in the other car. So, sounds like they are charging the other car's battery for 15 minutes at a lower rate, which may or may not be useful depending on the problem in the other car. Personally I would rather just use jumper cables (but I agree the Model S isn't a good source for that either).

It's been a long while since I had jumper cables. Instead I have something like this - they have versions that include a tire inflator, which would at least be useful for the Tesla.

Not true if you use one of those jumpers that works by plugging into cig lighter

The lugs are also useful for jumpstarting the MS if the 12V goes flat; a booster battery can sit in the frunk and stay hooked up while you maneuver it to a Service Center or the like.

Just replaced the garbage 12v battery that comes standard in the Model S with a Odyssey. Hopefully the problem is not with the undersized dc to dc converter that Tesla has been using in the Model S. This replacement should at least mask the low voltage issues for a few months/years before another replacement.

@SMOP - What low voltage issues?

Damaging your Model S trying to jump start someone is revolting.

If you connect to the wrong batteries the other car will get flipped onto its roof!


It's the second time my 12V is dead. Did you replace the OEM battery yourself? What were your issues prior to that?


I picked up one of these awhile ago:

Works like a charm for jump-starts and flats. There are cheaper units available. Has come in handy several times.

The Model S is designed NOT to help ICE cars. hahahaha

You absolutely can jump start a car or anything else 12-volt with a Model S. Pop off the nose cap and hook up to the color coded 12 volt studs. I started a dead ATV last weekend with our Model S.

Maybe an ATV, but you are risking drawing too much current trying to jump start a car. I believe the manual tells you not to do this.

An ATV's engine takes a lot less cranking power than a car.

I suppose this means Model S is not backwards compatible :P

@SMOP Ur replacement battery working out for you?

As others have said, you can jump another car with the Model S. In fact, I had to jump start my wife's Volt with our S. Not easy to pop off the nose cone to get to it but it can be done.

I jump started our diesel F-250 yesterday using the Model S. One of our employees left the truck with an empty trailer at a local boat ramp, ran the boat five miles around to our property and took an ATV back to get the truck - oops, key still in ignition, engine off, ignition on, dead battery. He called me and I took the S and jumper cables over to the truck, popped the nose cone, hooked up and it started right up.

The deep cycle batteries in the Model S are regular car batteries and there is no reason that they cannot be used to jump an ICE. Brian's comment above that they are smaller motorcycle-size batteries is incorrect. I dug around and found mine behind a panel in the frunk area. Normal, full-size battery.

Tesla does not advise doing this, but it does work. Your mileage may vary...