i have Porsche carrera 996.2 MY 2002 3,6 engine , and i change to new battery Exide 77AH , after almost 1 week the car was flat battery. The reading was 10.3 Volts.

I check if any lamb of the trunk or rear of the boot or a any other device left on but all was ok.

Pleas be noted that the car has navigation and alarm.

i always locked the car with alarm and i am driving it once a wee or twice.

please help.

Best regards
Marios charidemou
CYPRUS

Sounds like you definitely have a draw unless your 2 trips/week are very short ones that aren't replenishing the power used to start the car. Anything aftermarket installed, (dash cam, stereo with aftermarket amp, Bluetooth kit, etc) that might be drawing more than nornal current?

Probably the best way to figure out which circuit is to get inside the car, lock the doors by pressing the button twice quickly, which defeats the internal motion sensor, then comfort yourself down to the fuse panel with a multimeter methodically going through all of the fuses monitoring any amperage draw by touching the backs of the fuse contacts.

Thanks a lot for your help!!!! I will try all of your kind guidance and check all the fuses. All extras of the car are factory fitted there are nothing aftetmarket.

thanking you very much for your kind help
best regards
Marios
Cyprus

Are you leaving the key in the ignition? If so remove the key and your problem is solved!

You must have missed it in his initial post, which says -
The other option is to hardwire in a pigtail to a C-Tek or Battery Tender battery maintainer and just plug it in when you park it in the garage so it keeps the battery charged. I plug in all my P-cars when I park them since it could be a couple days or weeks before one of them goes out and then I don't have to worry about low battery issues when I do decide to drive one. I use the Battery Tender brand and have a couple of their multi-bank chargers where there are multiple charging feeds from the same primary unit - works great and is less expensive and cleaner looking than buying multiple independent units. Both are available on Amazon.

hi! Thanks for reply!... i never leave the key on , i always locked the car
And the alarm is enabled!... is the alarm consuming a lot of power in order to flat the battery in 1 week?

Thanks very much for your reply and help!
This must be good idea to buy battery tender so as to be always fully charged ....my best regards!

The car consumes the least amount of power when its locked as it puts some of the systems to sleep, do you're doing the right thing by locking it in your case to try and preserve battery power.

Its the harness that goes from starter /batter/alternator. Replace it and you will be good to go.

I've got a 2006 997.1 C4 Cab. Which Battery Tender charger would I need? Can't quite figure it out from their website....

Nevermind, figured it out....

?
AFAIK
That’s more a solution for a slow crank/no crank when engine is hot.
But once enough sitting time passes, the engine stars no problem.

The op appears to have some sort of constant draw from battery.

I would re-charge the battery fully and see if the problem persists. It can be one time thing (i know, u said u checked everything)

Battery tender will only cover up the problem, if there is a problem. imo
U should have one anyways tho. Lol