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Flat battery


New member
24 Jun 2006
Hi guys,

I picked my 996 up on Saturday. I have been driving it all weekend with no problems. Tonight when I went to start her the alarm went off, I tried to stop it with the key fob but that wouldn't turn it off. Even after starting engine it kept going so I closed the door and waited for it to stop. When it did I rang Porsche assistance. They told me to open the car using the key and this disarms the alarm and resets it. Ok I thought that's good as I dont want to drive home with the alarm going. Then when I went to start it the car was dead, it just clicked. (windows popped up and down and it made a clicking noise) I eventually got it started but the battery sounded like it was very low. The assistance people told me to go for a drive to charge it up. I went for 30 mins and since I have been back I have started it 4 times so the run did it good. Things is will the alarm be ok now? Also why was the battery dead ? I dont get it ,I I have 14 on voltometer too ? Porsche in reading are picking it up this week anyway to fix my seat fuse that keeps shorting out so I cant move seat so I will advise them of it. Any ideas? I am scared to drive it now in case I can't start it?


Migration info. Legacy thread was 65176
worth getting then to check over the volts drain as it sounds the elec's are doing a fiat !

Migration info. Legacy thread was 65198
whats a fiat? Or do you mean as in Fiat cars electricals?

Migration info. Legacy thread was 65202
yes :D

could be 1 gremin causing more problems......

but with the volts reading at 14+ then it could be over-charging, i,e, look for bad regulator or regulator ground, or wiring problem, etc etc

Migration info. Legacy thread was 65208
They are picking it up this week anyway as the seat fuse keeps blowing so I reckon it could be connected .

Migration info. Legacy thread was 65209

sorry to say, I think your battery is dead, sounds very like what happened to me. driving round for 30mins won't put the charge back properly ,and there is some evidence to suggest that once a porsche battery goes flat, the damage that is done, means that even after charging it properly, it will not hold its charge properly again.

Sound like you have a volt drain that caused this...

The 14v from the voltmeter when engine is running, is a red herring, thats just coming from the alternator...

look here for bit more info, i went for bosch silver battery as the OPC wanted £150 for their battery...I have got a solar trickle charger..., if you have mains in a garage, go for one of those...Porsche are notorious for having backward wiring, i guess they spent the effort on getting the handling right... :D



Migration info. Legacy thread was 65211
I drive up the road though and it charges itself up again. Anyway i have a years warranty, they will sort it this week :)

Migration info. Legacy thread was 65213

See that link from F1_Dragon, some good stuff on there.

As for charging it up... If you had a professional battery charger it might take 5-6hours. I have the pretty chunky CTEK 7000 and it takes 12 hours.

You cannot charge a drained battery by driving it (unless you are driving for 12 hours). It needs to be fully re-charged by a three stage mains charger. If you dont give it a full charge, then you kill it very slowly.

If you are still getting problems after Porsche look at it, just ask me for a v good porsche electrician in South West london.

Good luck,


Migration info. Legacy thread was 66858

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