55 Plate Cayman S Parasitic Battery Drain

[JK51AML]

Have the above car and it has started to eat its battery.

RAC came out, swapped out the battery, but noticed a 2.5amp drain when the vehicle is off.

No interior lights on etc.

Over night it ate its battery again.

So far I have eliminated the radio being the issue (pulled the fuse and it still ate the battery).

I am wondering about a dodgy diode in the alternator so will charge the battery again and see if the alternator gets a little warm from drawing the power.

It has also been suggested could be the alarm causing the issue (battery backup for the sounder constantly drawing power)...?

Has anyone else suffered a 2.5amp battery drain killing their car and what was it (I'm just looking to narrow things down) before I test every fused circuit.

Thanks guys

[A1VDY]

More than likely it's a fault with the alternator.
Have you also checked the charge rate, battery should show 14.2volts running..

[Scrump]

Does it have a tracker fitted?
I have heard tales of these causing battery drain when the tracker internal battery has died.

[gsewell]

My tracker used to draw about 100mA and would flatten the battery in 10 days.

[jakesmith]

Obvious places to start are alarm, tracker
With tracker, they have their own internal battery but when it fails they car start being powered from the car's battery instead.
If you haven't changed anything and this has started happening I'd check that
Internal lights including in the boots, have you checked those - set your iphone to record a video, put it in the boots and close them and check they go out could be a failed switch
If you have the time & patience then you could buy this and leave the car overnight with different fuses out and see which fuse you pul that stops it dropping
https://www.amazon.co.uk/TONWON-Bluetooth-Wireless...
I had a similar issue with my R8 and it took the arage 2 goes to troubleshoot it. Turns out it was an incorrectly installed switchable exhaust that was wired to a perminant live not a switched live so if I parked it in quiet mode the car was using the battery to keep the solenoid open and running flat
I know these faults are very annoying but on the bright side, they aren't as hard to troubleshoot as the worst one, the dreaded 'intermittent' electrical fault.
Good luck

[Steve H]

2.5a is pretty big, alternator is an option for sure but failing that either measure the drain and pull one fuse at a time or get hold of a heat sensing camera, put the car somewhere with a stable temperature (garage/workshop, no direct sunlight) and see where the hot spot is.

[So]

JK51AML said:

Have the above car and it has started to eat its battery.

RAC came out, swapped out the battery, but noticed a 2.5amp drain when the vehicle is off.

No interior lights on etc.

Over night it ate its battery again.

So far I have eliminated the radio being the issue (pulled the fuse and it still ate the battery).

I am wondering about a dodgy diode in the alternator so will charge the battery again and see if the alternator gets a little warm from drawing the power.

It has also been suggested could be the alarm causing the issue (battery backup for the sounder constantly drawing power)...?

Has anyone else suffered a 2.5amp battery drain killing their car and what was it (I'm just looking to narrow things down) before I test every fused circuit.

Thanks guys

It's got a tracker on it that you don't know about.

Is my guess.

Been there, done that, had the OPC bill for sorting it out (though Porsche kindly paid some of it).

[KPB1973]

Does yours have the amp in the frunk? Mine was drawing a lot of...amps...(no pun intended) even more so than the aftermarket stereo. Since disconnecting both i've had no issues at all. Mine has a Tracker somewhere too.