mh996

Hi everyone - I have a 2004 996 TT Cab which i bought new. It now has 20k miles and has performed wonderfully until now. The problem is that I can't start the car without a jump and don't believe it's a battery problem. Alternator seems more likely. Here's why:

1) the battery is only 2 years old
2) the battery won't hold enough charge after hours of running to start the car or to operate the engine fan. However most of the things that usually don't work with a drained battery do work (radio, A/C, engine hood opener etc). Another strange fact is the part that the battery won't charge at all but has enough charge to enable the radio, a/c etc.

Can anyone:
1) tell me how you know if the alternator isn't working?
2) recommend a trusty mechanic in rhode island

I'm thinking of taking it to Autozone simply to measure voltage etc. first.

Thanks for any advice.

Martin


Thanks,
Martin

adam_

You need to measure the current delivery capacity of the battery- NOT just voltage.

The symptoms are perfect for bad battery. 20k miles? You probably don't drive it enough and the battery has failed. Porsche will not warrant a battery with under 5k miles per year.

mh996

Thanks for the advice. I will have them measure both. It is the second battery and only 2 years old. But it could be the battery. I'm just surprised since it seems sudden and binary (i would have thought a battery would gradually get worse).

Loren

Have the battery tested for load and have the specific gravity in each cell tested.
I have seem less than 1 year old batteries go bad.

Land Jet

Get a battery maintainer and always lock your car. Leaving it unlocked keeps everything on standby which drains the battery.

wross996tt

If you get a proper maintainer, you do not need to lock the car. It is true that the car will go to "sleep" after 5 days if locked, but there is still a drain on the battery and without the maintainer the battery will die. It seems there are more issues with a locked car than without FWIW.

slant911

A simplistic test you can do quickly is to measure voltage at the battery with the car running (once you get it running). You should be seeing in the mid to high 13V range. If not your alternator could be suspect. I agree with above though that the battery sounds like it's toast. Don't just replace the battery though thinking all is OK if it starts. The alternator could be bad and contributed to the early demise of the battery.

mh996

Hi everyone. Thank you for your help. The culprit was indeed a dead battery. I replaced it with an inexpensive autozone replacement.