Porsche Enthusiasts Club Forum

Hi, can you help. Whilst coming off the motorway at 70 mph, the battery warning light came on. During the 1 mile journey from the junction to home, various warning lights flashed ABS, take your car straight to the dealer and some others. Excuse my poor memory for not noting everything, as my mind was focused on getting home. As it was late I decided to leave any inspection until the following day, where upon I found the battery to be at 0.5V and thus unable to proceed further that day. With the battery fully charged using an Optimate, I am now able to start the vehicle which shows over 16V when running. I should add that I recently changed the battery (four weeks previously) as after the recent cold spell my oe battery from 2003 gave up the ghost. I would say that for the previous 12 months or so, the voltage during running at shown 13V and not 14V as when I originally purchased the vehicle over 2 years ago.

My question is, I suspect the voltage regulator and or brushes (hence over charging at 16V or undercharging at 13V). Does anybody have any advice and how difficult/easy is it to remove the alternator from a 996 Carrera 2

Hi

A battery CANNOT read 0.5 volts unless its DEAD and I mean totally...it would not even recharge....

Unless your meter is no good.... even a dead (no start car) battery would normally read around 8 volts...

The other end is that obviously the alternator should charge at between 13.9 to 14.2 volts....NEVER 16..volts

If I were you I would take it to an auto electrician to have it all tested...

All the best Brett

Thanks for the info Brett, but I can only tell you what I see.

The car is parked up on my gf's drive until I decide what to do. I trickle charged the battery using an Optimate3, which when charged over several days showed the ! charged light, which apparently indicates a battery fault. Remember this was a recently purchased battery.

Fitted to the vehicle it measured 12.54v with the -ve lead disconnected. Connecting the -ve lead indicated a spark and the ammeter showed a drain (different values on different scales - frustrating - I should read the instructions!).

Starting the car the voltage across the battery terminals went to 18.6v, with the familiar smell with an overcharging battery.

I have been told that the alternator should be bullet proof and that the likely fault is the battery and the alternator trying to charge it as much as possible. Don't shoot the messenger, I am only telling you what I have been told. This may support what the Optimate charger tells me.

I think my first port of call is to have the battery checked.

Not sure why I get an ABS warning message and brake distribution warning message also.

Any suggestions welcome.

Hi

Yes definitely get the battery checked as I suspect it has TOTALLY dead cells....

The warning messages woud be caused by incorrect voltages....dont worry about them until the battery/charging problem is sorted....

Battery replaced (under warranty ?) first...

All the best Brett