My Boxster’s Battery Died

At the end of last year, I hadn’t driven my Boxster for a while. I think it was left unused for over a month and a half.

Then, one day at year-end, I tried to get in the Boxster and pressed the key button, but there was no response at all. The key’s light was on, so the key itself seemed fine.

I tried several times, but still no reaction.

It turned out to be an unexpected dead battery. I had replaced the battery with a new lithium-ion battery (Mega Life Battery) back in June last year, and the one-year inspection showed no issues, but suddenly the car lost all power.

What I could think of was that since the last Okayama-Tottori touring trip, I had only been taking short drives, and I had installed a dashcam and radar detector wired to the 12V cigarette lighter socket.

The 12V power from the cigarette lighter socket stays on for about 20 minutes even after the engine is turned off, so short drives and frequent door openings can drain a fair amount of electricity.

Also, I heard there’s a certain amount of parasitic drain even after 20 minutes, so that seemed suspicious.

First, Open the Door with the Emergency Key

I started by reading the online manual to find out how to open the door with the emergency key.

First, remove the emergency key from the remote key fob. Then, lift the driver’s door handle up to reveal the keyhole, insert the key, turn it left, pull it out, and lift the handle again to open the door.

I tried this, but it wasn’t easy. The emergency key is small and hard to turn, and since the keyhole isn’t used regularly, it was stiff and difficult to rotate. My hands hurt as I tried turning it left, but it wouldn’t turn fully. I kept pulling the key out and trying again, re-reading the instructions to make sure I wasn’t doing it wrong, but no luck.

No matter how many times I tried, it only turned partially left, and the key wouldn’t come out.

Just as I was about to give up, I pushed the key in a bit deeper and tried turning it again, and it finally turned about 90 degrees to the left.

Then the key came out smoothly, and when I lifted the handle, the door finally opened. It took about 10 minutes.

Powering the Trunk via the Fuse Box to Open It

Next, I tried to open the trunk where the battery is located, but the trunk opener on this generation of Porsche is electric, so if the battery is completely dead, the trunk won’t open at all.

Normally, since this Boxster has a Mega Life Battery, pressing the emergency button on the battery would allow it to start from the backup power source, but since the trunk wouldn’t open, I couldn’t access the battery.

So, I had to open the trunk using an emergency method as well.

First, open the fuse box cover located at the left footwell of the driver’s seat, take out the fuse remover inside, and pull out the ‘positive terminal.’

Then, connect the positive terminal of a portable car battery (jump starter) that you brought with you to the pulled-out terminal, and connect the negative terminal to a metal part near the door hinge. When you turn on the power of the portable battery, it supplies power, allowing you to open the trunk using the trunk opener switch.

By the way, air-cooled Porsches like the 964 have cable-operated trunk openers, so even if the battery dies, there’s no problem. But electric openers like this can be troublesome in situations like this, so I wish they’d stop using them.

Accessing the Battery and Restoring Power

Finally able to access the battery, I pressed the emergency button on the Mega Life Battery. The car powered up, and the lights came on. (With a regular battery, this is where you’d connect a portable battery and jump-start the car.)

Turning the key in the driver’s seat, the engine finally woke up as usual.

Once the idle stabilized, I pressed the emergency button again to switch back to normal mode. This started charging the battery.

Lithium-ion batteries charge and discharge very quickly, so just about 15 minutes of driving is enough to recharge. I took a drive on the Hanshin Expressway for about an hour to fully charge it before returning to the garage.

Then, just to be safe, I checked the battery’s health status a few days later.

Make Sure to Review Emergency Procedures in Advance

Having experienced a dead battery, I realized that since it happened in my own parking spot, I was able to stay calm and handle it. But if it happened somewhere else, it might have been much more difficult.

If possible, I strongly recommend reviewing how to use the emergency key and how to open the trunk beforehand. Having even one experience beforehand will give you peace of mind and help you handle the situation smoothly when the time comes.