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How to test & replace battery on Porsche 911, Cayman, & Boxster (2005-2012)

Maintenance Interval: Every 2 years regardless of mileage

Dealer Cost: ~$500 (if replacing battery)

DIY Cost: ~$300

Difficulty: Very easy 

Repair Time: 20 minutes


It's important to always have a good battery in your car, so you aren't left stranded. Car batteries typically last around 5 years. However, depending on your driving conditions and climate, your battery may not last this long. Porsche recommends testing your battery every 2 years. To replace your battery, check out this helpful tutorial above from the YouTube channel, Saad Ahmed. While the video is for a Porsche 911, the same exact procedure also applies to the 987 Boxster and Cayman. Detailed battery testing and replacement instructions can be found below.

Vehicle-specific tools you'll need for the job:
↗️Mechanic's tool set
Vehicle-specific parts you'll need for the job:

Battery testing instructions:

  1. Start by testing your battery. You can do this by taking your car to your nearest auto parts store.

    1. To test the battery yourself, purchase a simple battery tester such as this one.

    2. Open vehicle's hood, then locate the remote battery terminals on the driver's side under a plastic cover.

    3. Remove the plastic battery terminal cover and attached the battery tester.

    4. Run through the battery tester's battery and crank tests. Here is a helpful video from Scotty Kilmer:

Battery replacement instructions:

  1. If your battery is bad, proceed with the following steps to replace it.

  2. Open the front compartment area on your vehicle

  3. Remove the plastic battery compartment cover by twisting the two plastic clips

  4. Remove the battery tie down clamp using a 13mm socket and an extension.

  5. Loosen the battery terminals using a 10mm socket or wrench.

  6. Carefully wiggle out your old battery and lift it out.

  7. Insert your new battery.

  8. Re-attach the battery tie down clamp and hand tighten it.

  9. Place the battery terminals onto your new battery and hand tighten the 10mm bolts.

  10. Replace the plastic battery compartment cover.

  11. Clean up your work area and put away all your tools.

  12. You're all done!