gti2kids

HI,

I just got my Cayman S delivered to my house. The battery was dead, and the trailer driver jump started it. I parked the car in my garage and hooked it up with my battery charger (most likely not a Porsche approved model).

After about 10 hours charging with 2 Amps, the battery seems fully charged, but I noticed the battery sounded like it had a lot of bubbles popping inside, even after I disconnected the charger.

I didn't notice such sounds when I charged my other cars (Infiniti and Honda).

Is this normal? Are those really sounds of bubbles, or some sort of fan that was turned on by temperature (the battery is warm but not hot, like maybe 110 degree Fahrenheit max.).

gti2kids

By the way, I charged the battery for 10 hours and it showed 12V. However, 9 hours later, it drops down to 5V. I had shut off all electronics in the car and closed all doors. The only door that was opened was the front trunk lid.

Does this mean that my battery is completely dead?

Jim Michaels

Sorry that you've not gotten any help. I'm no expert, but it doesn't sound good for your battery; not holding a charge and a chemical reaction during charging. Also, I think you should be getting a little over 12 volts on a fully charged healthy battery.

A battery can be replaced easily enough, but the next concern might be to find out why the battery was dead when the car was delivered. Has it not been driven or charged in a while, or has the battery been "leaking" power to some electrical fed component that should be off but isn't?

For future reference, the front trunk light can be turned off while the trunk is open by inserting the tip of a screwdriver in the right side of the lower latch mechanism and pushing the same little lever that shutting the hood pushes.

I know this isn't a great start (so to speak) on your new used car, but I hope it all straightens out real soon.

BostonDuce

Bubbles are hydrogen gas which combined with the heat means you are cooking the battery=not good. Be careful with sparks around a battery that is giving off that much gas.

A fully charged, serviceable battery will be somewhere around 13.5-13.8 volts-12 volts after charging is not enough. If you are seeing 5 volts you may be too far gone to bring it back.

Get yourself a CTEK, Porsche Battery Charger, or Battery Tender charger which will not cook the battery during charging.

Your trunk light should have shut itself off after several hours.

AFA problems to investigate; Battery, bad cables/ground, alternator, dead short.

BD

gti2kids

Thanks everyone for the replies. I actually just bought the car as a CPO in Florida and shipped it California. The truck driver told me that the car needed a jump start when he picked it up in Florida. Also, the car sat in the showroom for about 1 month after I paid for it but couldn't arrange shipping .... so there was no doubt that the battery was dead.

Anyway, the seller agree to pay for a new battery, so I just went to a local dealer and picked up a 80 Amp battery for about $280. Installation was mostly easy. However, to pull out the old one, I had to step one foot into the front trunk, or else I bet I would definitely break my already fragile back. Dropping the new one in required a similar awkward maneuver.

Does anyone know a better, less painful way for putting in a new battery?

I could have towed the car to the dealer for them to install the battery (with Road Side Assistance) but that was just too much trouble.

BradB

Just went through this myself. I also stepped in the trunk-there is no other way.

BTW, I paid $100 for a proper battery replacement. For $280 I would expect the car to start itself!

STLPCA

I assume that with a CPO car the seller paid for a new Porsche part numbered battery which is certainly not $100

Make sure the new battery is properly vented (connected to the hose running to the R front lower wheel well).

smlporsche

Also, unless you drive the car regularly get yourself a battery tender that plugs into your cigarette lighter. I bought one from the dealer when I bought my Boxster in '03 and still have the origianl battery. Best $75 I ever spent.

mikefocke

A chance the battery is bad because it sat around on a lot for a long time. But it also can be bad because it was charged using a too high voltage charger or the voltage regulator is bad. So I'd go to the dealer or a battery store and spring for a complete load test (or buy the tester yourself...~$100) which should also report the health of the charging circuit.