how to replace the battery in my Tesla Model 3 Original (2017-2023)

Tesla Model 3 Highland (2024-present)

Error Codes

1-2 hours

Time

medium

Difficulty

medium

Severity

3 min read

511 words

Problem Statement

Step-by-step guide on how to replace the 12V auxiliary battery in a Tesla Model 3 (2017-2023). Includes symptoms, diagnostic steps, and safety warnings.

Affected Component

Electrical

Estimated Time

1-2 hours

⚠️ Safety Warnings

Important safety information - read before proceeding

•Disconnect the vehicle from any charging source before starting work on the battery.
•Wear safety gloves and goggles when handling batteries to prevent acid exposure and electrical shock.

Symptoms

•12V battery low warning on the display
•Non-functional interior lights or infotainment system
•Difficulty unlocking or starting the vehicle
•Inconsistent operation of electronic features (e.g., windows, doors)
•Frequent need for jump-starts

Diagnostic Steps

1
Inspect the vehicle display for any warning messages related to the battery.
2
Check the voltage of the 12V battery using a multimeter; it should be around 12.6 volts when fully charged.
3
Verify the condition of battery terminals for corrosion or loose connections.
4
Assess the age of the current battery; if it's over 3-4 years old, it may need replacement.
5
Review vehicle logs using the Tesla app or service menu for any battery-related alerts.

Solution

💡 Expert Tip

For complex repairs like this, consider taking photos at each step. This helps if you need to reverse a step or consult with a mechanic. Also, keep all removed parts organized - you may need to reference them during reassembly.

Verification

After completing the repair, verify that the issue has been resolved:

✓Test the affected component to ensure it functions correctly
✓Check for any error codes or warning lights
✓Monitor the vehicle for a few days to ensure the issue does not recur

Prevention Tips

To prevent this issue from occurring again:

•Follow the manufacturer's recommended maintenance schedule
•Address warning signs early before they develop into major issues
•Use quality parts and fluids recommended for your vehicle
•Keep detailed records of all repairs and maintenance

Tools & Equipment Required

•Socket set
•Torque wrench
•Flat-head screwdriver
•Multimeter

Parts Required

•New 12V auxiliary battery (specific to Tesla Model 3)

Related Faults

Share this solution

Comments

No comments yet

Be the first to share your thoughts

Back to Generation

Diagnostic Steps

1
Inspect the vehicle display for any warning messages related to the battery.
2
Check the voltage of the 12V battery using a multimeter; it should be around 12.6 volts when fully charged.
3
Verify the condition of battery terminals for corrosion or loose connections.
4
Assess the age of the current battery; if it's over 3-4 years old, it may need replacement.
5
Review vehicle logs using the Tesla app or service menu for any battery-related alerts.

Solution

1. Preparation

Gather tools: socket set, torque wrench, flat-head screwdriver.
Ensure the vehicle is parked and powered down.
Open the trunk and remove any items obstructing access to the rear under-cargo area.

2. Access the Battery

Remove the plastic cover over the 12V battery by unscrewing the retaining screws.
Use a flat-head screwdriver to gently pry up any clips holding the cover in place, if necessary.

3. Disconnect the Old Battery

Locate the negative (-) terminal first and disconnect it using the appropriate socket size.
Next, disconnect the positive (+) terminal in the same manner.
Carefully lift out the old battery, ensuring to handle it securely as it may be heavy.

4. Install the New Battery

Position the new 12V battery in the tray, ensuring correct orientation (positive and negative terminals match).
Connect the positive (+) terminal first, tightening the connection securely.
Connect the negative (-) terminal next, ensuring a secure fit.

5. Reassemble and Test

Replace the plastic cover over the battery and secure it with screws.
Reconnect any removed components in the trunk area.
Power on the vehicle and check for any warnings or alerts on the display.