Can You Charge a Tesla with Jumper Cables? Top Tips

Charging your Tesla is a top priority. If your 12V battery is completely flat, you can’t get into your car. If your High Voltage is flat, you can’t go anywhere. The question is can you jump-start it to get moving? I’m a mechanic, and I’ll show you when and how to jump your car.

Tesla can be jumped if the 12V battery is flat. The High Voltage battery can’t be charged using jump cables.

In this article, we’ll look at when you can use jumper cables and the different types of batteries in your Tesla.

Infographic - Can you charge Tesla with Jumper Cables

Using Jumper Cables on Your Tesla

Every Tesla has two batteries, a 12V battery, and a High Voltage battery. The 12V battery controls all auxiliary areas of your car; locking, unlocking, lights, windows, and the touch screen. So although it’s not running the car, without its power, you could be in quite a pickle.

The High Voltage, on the other hand, allows the car to move and drive, but they are very different systems, and if your high voltage is flat, no amount of jumping will get you driving again.

Jumping Your 12V Battery

There are a couple of reasons why you might find you have a flat 12V battery which will require a jump charge

  • You’ve left lights or media on with no power running
  • 12V is at the end of its life
  • Haven’t used your Tesla in a while

Any one of the above will leave you with a flat battery and some puzzling to do.

Locating Your 12V Battery

Unless you are very much into cars and how things work, you probably are not 100% sure where your 12V lives. Don’t worry; most people don’t. Your 12V battery lives in the trunk area, but with no power, how do we open the frunk to jump the battery?

Tesla thinks of everything.

Depending which Model you own will determine how to open the frunk latch. In recent years Tesla has placed access leads in the tow circle at the front of the vehicle.

To release the frunk latch, follow these steps:

  1. Locate a power supply, i.e., a booster pack
  2. Release the tow cover by gently pressing on the top left of the circle
  3. Two wires should be visible: One Black and One Red (Either can be attached to the tow circle)
  4. Gently pull the cover and two wires toward you
  5. Connect Red to Red and Black to Black on your booster pack
  6. Turn on the booster
  7. The latch should immediately release

Now that the frunk is open, you can continue to locate your 12V.

On older Models, the latch releases are behind-the-wheel arches. You will need to gently pull the covers away to locate the pull cords.

At the top of the frunk is a dust cover. Remove this by pulling upwards. There are small clips holding it in place. Under this, there is a smaller cover; you need to remove this, also. You should now be able to see your 12V.

Like before, join your Booster pack, Red to Red and Black to Black.

If you have an S, you will need to pull the connector housing to the left and remove the cover from the red jump post before connecting the Red to Red and then Black to any metal component on your car.

Begin the charge.

This can take up to 10-15 minutes, depending on how flat your 12V is.

You should now be able to start your car.

If it doesn’t start up, give it another 10 minutes. If you haven’t used your Tesla in a while, it might need some more time.

If it doesn’t look like it wants to start, then, unfortunately, your 12V may be at end of its life, and you will have to purchase a replacement.

Remove the Jumper cables in the reverse order.

It’s important to note that you shouldn’t jump your Tesla from another Tesla or EV. You can do irreparable damage to the computers. If at all possible, use a Booster pack and not an ICE vehicle.

Charging Your High Voltage Battery

There are only three ways to charge your high-voltage battery.

  1. Level 1 charger
  2. Level 2 charger
  3. Supercharger

None of these involve jumper cables. In reality, there is no way to connect jumper cables to the High Voltage battery, and no attempt should be made to try.

You most certainly will destroy your High Voltage and could cause serious injury to anyone involved.

Model S and X 12V Battery

In late 2021 Tesla launched their new 12V battery for the Model S and the Model X. Instead of the traditional acid-filled battery of old, the S and X now have Lithium Ion batteries.

Although still listed as a 12V, they are, in fact, more like 16V.

Tesla had some issues with their original 12V (which is still installed in the Model 3 and Model Y). They just weren’t going the distance. A traditional 12V should last about 3-4 years, but some of the S and X batteries were failing much sooner.

This was not a good look for Tesla, as, after all, they are a battery manufacturer, and so they decided to replace the 12V with the new Li-Ion.

The new version is incredibly light, at only 1.8kg, compared to the acid battery at 18kg. It also has a much higher capacity which, in theory, should mean that you never have to jump it. It also behaves much better in extreme climates, from -10C to +45C.

The Li-Ion draws energy from the high-voltage battery. If for any reason, it does go flat – you’ve been away for an extended period, or you haven’t charged the high voltage in a while- there is still the ability to jump the new battery.

We access it similarly and attach the jumper cable to the red by removing a cap on the jump post. The black cable is then clipped to any metal point in the trunk. And the booster pack is switched on as normal.

Other posts you might find useful:

Is it better to charge a Tesla slowly?

Tesla won’t charge in the cold

What to do if Tesla battery dies

E John Cunningham

Hey, I’m John and I'm a technical writer here at I’m a Red Seal qualified Auto Service Technician with over twenty-five years experience working on Classic and Modern Cars. I've worked for GM, Jaguar, Land Rover, Volvo, Audi, and VW main dealers. Yep, I’ve skint my knuckles on them all!

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