How To Replace a Tesla 12V Battery (Step-by-Step Guide) 

When your Tesla’s 12-volt battery dies, you need to know how to replace it. This guide will show you how to replace a Tesla 12V Battery in a few easy steps.

Keep in mind that removing the old battery and installing the new one can be a bit challenging, but it’s definitely doable if you’re patient and careful. So, without further ado, let’s get started!

Tesla cars use renewable energy sources but they still use a 12-volt battery to run the display panel, doors, windows, and lights. This battery needs to be replaced for the car to run.

There is a full video at the end of this article to help out as well. Plus, if you need peer advice from fellow Tesla owners, check the very active Reddit forum.

How To Replace a Tesla 12V Battery Step-By-Step

While you can call your closest Tesla service center and ask for one of their certified mechanics to change the battery for you, you may have reasons for doing it yourself.

Follow this step-by-step guide for changing a Tesla 12-volt battery.

Step 1: Turn off Tesla’s climate control system

You can do this through your touch screen. Go to the button on the bottom left corner—the one that shows the numbers. Once the screen pops up, touch the power button on the upper left.      

You know that you’ve successfully turned it off because the numbers are no longer lit up on the bottom left corner.

Wait 30 seconds to one minute just to be sure the climate control system has completely shut down.

Step 2: Prepare the vehicle

Before anything, prepare the vehicle to ensure safety.

  • Turn on the Park mode and open the car windows.  To park Tesla, you just have to press the tip of the drive stalk. Make sure you also fully open all the windows. This can help prevent you from locking yourself out of your car, or glass shattering.
  • Keep the doors unlatched.  Open both the left and right rear doors. Look for the door striker, which is the metal bolt and hook that allows the door to tightly seal shut when you close it. Since you don’t want the doors to latch closed when you’re changing the battery, block the striker by inserting a clean rag or hand towel through it. Step 4: Remove the seat cushion
  • Take off the second-row lower seat cushion. You just have to lift the cushion until you see the lever, and then slide it to release the cushion.  

Step 3: Turn off the vehicle and disconnect the voltage

Go to the Tesla touch screen, and select Controls. Then, select Safety and Security and Power Vehicle, and touch Power Off. 

To avoid electrocution, you have to make sure the high voltage is disconnected. To do this, open up your back seat and wriggle off the black plastic cover.

You will find a black cord that has a silver attachment. Just pull off (making sure that you are wearing safety gloves, and not standing on any wet surface).  

Step 4: Remove the old Tesla battery

  • Prepare tools. You will need gloves, safety glasses, and a 10-millimeter wrench.
  • Remove the under-hood apron. This is the panel located near the windshield wipers. You don’t need any tools—just gently lift one side until it pops off, then do the other side.
  • To get a clear view of the battery, remove the cabin air intake duct. This is the black plastic compartment on the upper part of the hood near the windshield wipers, and helps direct fresh air into the car. You can pry it off with your hands.  
  • Disconnect the negative battery cables. Wear the gloves and safety glasses, and get the wrench. Then, loosen the nut that connects the battery negative cable to the car battery.
  • Release the electrical harness. Remove the foam cover that is found in the right side of the Penthouse HV Cap. This reveals a small black and gray lever. Press it to release the electrical harness from the high-voltage controller connector. As it opens, you will hear a clunking sound.
  • Disconnect the positive lead. Remove the red cover to reach the 12-volt positive terminal. Then, get your 10-millimeter wrench and loosen the nut that holds the battery’s positive lead. Wriggle the positive lead free, then wrap it securely with a towel so it doesn’t touch any metal in the vehicle. Move it to one side.
  • Loosen connection to the AC compressor. Get your 10-millimeter wrench, and remove the bolt that connects the 12-volt battery upper tie-down bracket to the AC compressor bracket. The black strap will spring upwards. You can now lift it off easily.  
  • Remove the vent hose from the battery. Wriggle off the vent hose located at the side of the 12-volt battery.  

After all these steps are completed, you can now remove the old 12-volt battery from the Tesla, and put in the new one. You’re halfway done!

Step 5: Place the new Tesla battery, and reinstall connections

  • Reinstall the tie-down brackets. Just place the bracket, put the fastener in the hole, and tighten.
  • Do a quick clean-up. If you notice any dirt and corrosion in your battery terminals and cable connections, clean it up now. It can help prevent inconvenient and expensive repairs later on.
  • Reinstall the positive lead into the positive terminal. Gently push them into place, and fasten. Never pound the clamps, because this can cause internal damage to the new battery—and you’ll have to buy a new one, and go through the replacement process all over again.
  • Reconnect the vent hose. First, check the hose for any cracks or damage. If you see that it is still in good connection, just push it back into place. (Note: after you install the battery, place the vent plug on the side opposite of the vent hose. A new battery usually comes with a new vent plug.)
  • Reinstall the electrical harness. Return the electrical harness—the small black and gray lever you removed before—and lift the lever to snap it into place. Then, put the black foam cover on the right side of the penthouse. Cover it with the seat cushion. 
  • Reinstall the battery-negative cable. Place the cable into the battery terminal, and then tighten the fastener.
  • Place the cabin air intake duct. Return the black duct to its original place in the upper hood, underneath the windshield wipers. Once it’s snapped into place, you can put back the under hood rear apron. Press gently with your hands on all sides to make sure that it’s secure.

You’re done! Power on the vehicle and take your new battery for a test drive.