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2016 Model S 12V Battery Dying - What's the best replacement?

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Mike T. · rep 0 · May 25, 4:03 AM · 1 replies · solved · Question

Vehicle: 2016 Tesla Model S 75D

Hi everyone,

My 2016 Tesla Model S 75D has been giving me '12V Battery Needs Service' alerts on the screen lately, and sometimes the car won't wake up immediately. I've had it checked once, and they said it's getting weak. I'm looking to replace the 12V battery myself. It seems like a pretty straightforward job, but I'm wondering if there's a specific brand or type of battery that's recommended for Teslas.

Also, are there any precautions I should take before disconnecting the old battery? I don't want to accidentally brick anything or lose settings. Any advice on the best replacement battery and the process would be super helpful!

✓ Accepted solution

ClearTheCode Admin

ClearTheCode Team · rep 0 · May 25, 4:03 AM

0

ClearTheCode admin answer:

Experiencing '12V Battery Needs Service' alerts on your 2016 Tesla Model S 75D is a clear indicator that your low-voltage battery is nearing the end of its life. While the main high-voltage battery powers the drivetrain, the 12V battery is crucial for starting up the car's computer systems, lights, windows, and other accessories. Tesla typically recommends replacement every 3-4 years.

Causes of 12V Battery Failure:

  1. Age: Like all lead-acid batteries, the 12V battery degrades over time due to sulfation and electrolyte loss.
  2. Cycling: Even though it's charged by the main battery, constant charging and discharging cycles contribute to wear.
  3. Environmental Factors: Extreme temperatures can accelerate degradation.

Recommended Replacement Battery: Tesla vehicles often use an AGM (Absorbent Glass Mat) 12V battery. When purchasing a replacement, ensure it's a deep-cycle AGM battery with similar cold cranking amps (CCA) and dimensions to the original. Many owners opt for direct replacements from Tesla service centers or reputable aftermarket brands like Optima, Odyssey, or Bosch that offer compatible AGM batteries.

Step-by-Step Replacement Guide & Precautions:

  1. Safety First: Ensure your vehicle is powered off and in Park. Open the front trunk (frunk).
  2. Disconnect High-Voltage: For Model S/X, it's highly recommended to disconnect the high-voltage loop first. This usually involves opening a small access panel near the rear seats (check your owner's manual for exact location) and pulling the high-voltage loop release. This safely de-energizes the vehicle.
  3. Access 12V Battery: The 12V battery is typically located under the frunk cowl panel on the passenger side. You'll need to remove some plastic clips and the cowl panel to access it.
  4. Disconnect Old Battery: Using a 10mm wrench, disconnect the negative (-) terminal first, then the positive (+) terminal. Carefully remove the battery hold-down clamp.
  5. Remove & Replace: Carefully lift out the old battery (it can be heavy!). Place the new battery in the tray, ensuring proper orientation.
  6. Connect New Battery: Connect the positive (+) terminal first, then the negative (-) terminal. Secure the battery hold-down clamp.
  7. Reassemble & Reconnect HV: Reinstall the frunk cowl panel. Reconnect the high-voltage loop (push it back in until it clicks) and close its access panel.
  8. Power Up & Test: Power on your vehicle. You might see some initial error messages, but they should clear as the systems recalibrate. Check that all accessories are functioning.

When to See a Shop: If you're uncomfortable performing this procedure, or if you encounter persistent error messages after replacement, it's best to contact Tesla Service. They can perform the replacement and run diagnostics to ensure all systems are functioning correctly.

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