17 captured repliesDiscussion pagination complete · Source accounts, not a confirmed diagnosis
THIS DISCUSSION / SOURCE-DERIVED OVERVIEW
Discussion summary
YOUR RESEARCHParasitic Battery problem...Help!
Reported or suspected cause
alternator creating a 3amp magnetic draw
Reported cause
No successful repair reported for this finding.
1
Identified cause
0
Suspected cause
0
Reported fixes
Read evidence and context
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Discussions that report identifying a cause
1
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Reported cause · Original poster
Turned out to be the alternator creating a 3amp magnetic draw on the battery!!
Leading evidence: 'alternator creating a 3amp magnetic draw' (1 discussions report identifying this cause; no attributable repair resolution). Across 1 matching discussions, the most frequently mentioned possible cause is 'alternator creating a 3amp magnetic draw' (1 discussions; 1 report identifying it and 0 suggest it). The most frequently discussed action is 'Run )' (1 discussions). For that action, 0 discussions report a resolution and 0 report an unsuccessful attempt. No action has an explicit, attributable resolution report under the current rules. These are forum reports and suggestions, not a confirmed diagnosis.
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Explicit resolution reports before identified causes, performed actions and suggestions. Within each level, matching component labels precede direct query mentions and inherited thread context; successful versus unsuccessful discussion counts, owner confirmations and independent discussion support determine order. This is not a probability of success.
Discussions that suspect a cause
1
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Suspected cause · Original poster
They thought it was the ignition switch an spent $500 replacing that to no avail.
Explicit resolution reports before identified causes, performed actions and suggestions. Within each level, matching component labels precede direct query mentions and inherited thread context; successful versus unsuccessful discussion counts, owner confirmations and independent discussion support determine order. This is not a probability of success.
Discussions that contain suggestions
1
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Suggestion
(Assume the system is charging OK, voltage well above 13 when engine is running)
Counts describe captured discussions, not unique people or a diagnosis. Author identities are not reliably stored. Exact duplicate evidence is counted once across matching discussions; one discussion counts at most once per action/state. Multiple repairs reported together remain a combination. Suggestions and failed attempts do not establish a fix. Matches cover whole discussions and can include related faults, model variants and incomplete threads.
17 eligible posts · 0 unverified posts · 1 discussions match the subject in their title or opening post.
Rennlist: 1 discussions
0 evidence records excluded for query context · 0 excluded by outcome qualification · 0 adjusted by outcome qualification.
1 acknowledgements have no verified action link; they do not establish a repair result.
Outcome without a verified action link
The mechanic put in a rebuilt alternator which cured the problem!
I have a 1999 996 cabriolet with a serious parasitic battery drain. Already been to the shop and was told the drain spikes to 82 miliamps draw then goes flat and spikes again, etc. The key remote had died two years ago and the battery is new. They thought it was the ignition switch an spent $500 replacing that to no avail. I took the car back home and pulled every fuse and still it's draining overnight. No lights are on and the front boot light is disconnected. Any advice? Please help as nobody can figure it out! Think it's the alarm system? Convertible top? Do I need a new remote key?
Thanks in advance!
Are you sure it's 82 milliamps? That doesn't like it's enough to drain a healthy battery overnight. At that rate, it should take days. If it was 800 milliamps that would do it.
If it's only 82, is the battery still good? I understand it's new, but you never know as to whether it's holding a charge.
TamiyaGuy is right, you need a few Amps to drain the battery overnight.
Can't see the remote key being the cause.
Assume the battery is good? Was this replaced?
It maybe lasts 48 hours is there's a full trickle charge. This is the second battery in the last 90 days. Definitely a drain somewhere in the system. No aftermarket parts on the car at all.
Blackspeedster,
It is baffling
Since you have pulled all the fuses with no change, this SHOULD have covered the alarm also.
Perhaps worth doing same with some of the relays, in case one is stuck closed? Best I can think of.
(Assume the system is charging OK, voltage well above 13 when engine is running)
There are a bunch of posts about battery drains floating around. Do you by any chance leave the key in the ignition overnight? Do you close the driver side door and then reach inside the window and pull the key out? That can cause a battery drain.
AAHH! This is frustrating! Tried another battery - the 3rd. It's NOT the battery so it's still a drain problem. When I put up the power top, the driver's window no longer does anything but the passenger window moves. Maybe I'll pull the Window relay and see if that does it. Maybe the window relay is stuck open?
I pulled all of the relays and apparently none of them are for the windows. There must be a window relay somewhere? It's not in the fuse box!
I got my remote finally working as the red LED is coming on but it's not locking or unlocking the car. The car doesn't see the remote at all?
Blackspeedster,
IMO time to see an auto electrician, preferrably one that has Porsche or perhaps VW/Audi experience?
It is obviously a non obvious issue
Interested to hear outcome
Turned out to be the alternator creating a 3amp magnetic draw on the battery!! Dealer nor an independent could find it, it took a specialist auto electrician.
I had that same issue. Couldn't be alternator I thought, it's a rebuilt only 4 months old, but I traced it to the alt. Disconnected it and the drain when to near 0 a. Put this in the portion of your brain labeled, "things it couldn't possibly be".
Here's my 2 cents worth:
One possibility is that the Voltage Regulator was "leaky".
The regulator supplies the current to the field winding (rotor) at start up from the battery. Once the output voltage is achieved it switches from the battery to the output of the alternator. By varying the field winding it adjusts the magnetic field to give the required output voltage. Boring I know...
There is also a rectifier in there that converts the output AC to DC then back to the battery.
Hence the precautions in the manual about the procedure of connection and disconnection of the battery, so the regulator electronics doesn't get zapped.
