My Porsche 911 seems to have a battery leak or drain. Sometimes after only 3 days the car will not start. Is there anything obvious that I should look for?

A power leak could come from any electrical source including the alarm system even though you don't have it activated if the key is left in the ignition. If everything checks out okay (including the battery and the alternator), I would recommend using a "Battery Tender" device that could keep your battery at top charge level while it is just sitting there. Remember all batteries do discharge some as they sit for any length of time. If you have had an optional CD player installed or have heated seats, see if they are still using power while the car is "Engine Off, Key Out" of the ignition.

after you park take out negative terminal , when you put back and use again your car and it doesn't started again your battery is the problem, need to change.

Called a "parasitic" draw, it sounds like you've left something on. Make sure your hood is fully closed or the dome light shuts off, I know this sounds too simple, but this usually is the problem when a battery discharges this much and so fast.

Alternator will also drain the battery if it is going out.

Still having problems with the battery drain. I replaced the battery under warranty in September (3 months ago) but the problem is starting to happen again. It only takes about 3 days for the battery to drain enough so that the car won't start. The garage that replaced the battery also said the alternator and starter areally fine. The garage even attached a device that checked for any battery drain while the car was turned off and sitting show nothing unusual. They also removed the bulb in the trunk in case that was not shutting off. Is my only choice to keep the car on battery tender even if it's not driven for just one day?

Try removing the bulb in the trunk on the drivers side. If that doesn't work, have your battery tested.

3 possible causes - the front trunk light, the glove box light and the engine bay light. All are susceptible to micro-switch failure that defaults to 'light on permanently'. All of my 996's have had these fail. My current 996 had all 3 lights on permanently, the battery was going flat in 2 days. I replaced all the micro-switches and it has been fine since.

It hasn't worked out for me yet. I bought my car new in 2008 and the problem was there from virtually the start. I keep the car on a maintenance plug-in device and it does maintain the charge. Good luck after you've started it for about the third time. I won't start. This is humiliating. You are in a 100,000 car and it won't start when everyone is looking? This is the PROMINENT fault in this vehicle as of yet unaddressed. My new battery is now on an actual charger. Do you leave it there? Unplug and switch to maintain on cigarette lighter? Seven years and still unresolved.

Bring it to a shop that works on Porsche race cars. Not a stealership. They have people who continuously sort out electrical problems, particularly parasitic drains, such as yours. You're right, you should not have to put up with it. Good luck!

Hi, I've had my 996 Turbo -01 since 05 and experienced this battery drain problem ever since when I leave it for rest for a couple of days. I've found a temporary solution of the problem. I've experienced the same problem as you have, tried to change batteries and so on. Me and a friend of mine who's an electro engineer at Volvo did some serious trouble shooting, checking circuits, fuses, lightbulbs and so on and found out that the problem was that the car never goes into sleep mode. Normally it's active for two hours after taking put the ignition key, using some power from the battery to be ready to start again, before it gets into sleep mode, using power only for the alarm which is very little. The only way we could put the car into sleep mode was to reset the whole system by lifting the connection at one of the battery terminals and put i t back again. After this reset I could keep the car connected for the whole winter season (don't drive anything during the winter and keeping it in a shared garage) without any problems with the battery (the car did start) - a major difference than earlier when it didn't take any longer than 1-2 weeks before the battery was dead. A not so very comfortable fix in the long term, to lift the connection all the time, but a fix anyway. To fix this error completely i think we need to look at the data box - any other ideas?

I have a similar issue , My car when completely switched off is draining 0.10 amphere’s .

I had the same problem on my Porsche 997. 3 days was dead everything check out OK Then I met a Porsche racing engine builder in Sarasota he told just lock the car every time you get out and the car for 4+ weeks without driving it. And I only drive 2000 miles years What a blessing finding it is so simple but I have been doing it over 1 years and no problem. Porsche dealership could never find a problem and never told me what a simple fits but charge me plenty. You will thank me every time you don't have to jump your car.

The truth is and this comes straight from the dealership. You have to drive your Porsche min 400 miles monthly or warranty is void for replacement. Now!!! what does that tell us??? Porsche knows there's a engineering problem somewhere. Am I being paranoid???

I have a 2019 Macan S and drive the car daily but put fewer than 5000 miles a year on the car. When I go out of town for longer than 3 or 4 days the battery drains and I need a jump. According to the dealership the battery checks out good but I just don’t drive it enough. They said I have to change my driving habits or get rid of the Porsche. I’ve owned dozens of cars some very expensive and others not and never had this problem. I think it’s the battery and Porsche won’t swap it out, the reason being they use a battery that costs over a $1,000 instead of a normal $100 one. If you drive fewer than a few hundred miles a week I would not buy a Porsche. They know the problem but simply don’t stand behind their product. A lot of money for an unreliable car.

I have the same problem as several others here. If I don't drive my 2007 Porsche 911 Turbo every week, the battery will die. I usually keep the car on a charger in my garage, but I'm afraid to take it anywhere, because I can't trust it to start for the return drive. The battery is dead again, after I left it off the charger for a few days and didn't lock the car. So I guess it didn't go into "sleep" mode. Very frustrating problem -- wish there were a clean solution. Never had a car that ate batteries like this!

my 01 C4 cab is experiencing this. It's gotten progressively worse AFTER replacing the battery AND the alternator. I never lock it when in the garage, good to know about that. Has anyone tried pulling the fuse on the alarm curcuit? (Not sure which this is but someone suggested it to me.) I have to agree that Porsche is being irresponsible about this, esp learning that late model cars have the same issue. LUCAS ELECTRICS IN A $100K CAR? crazy