vove

Something is draining my battery but I cant narrow it down. After a two month trip I go to the garage and try to start the car, it didn't even crank. Went to get a new battery and she fired right up. After a week or two I got a RSR chip installed in my car and she ran fine for a day then the next day she killed the battery just enough to keep the clock running right but not enough to fired the car up. Went to check the battery out again and sure enough it needed replacement . Now, Im afraid to keep the car connected to the battery when parked because of the battery drainage problem Im facing. Yesterday I connected the new battery and went for a quick drive then I parked for about ten minutes. Came out to the car and it wont crank again, then I disconnected the battery then waited for about five minutes, reconnected the battery then she fired right up. What is happening to my C4? Anyone have a clue?

DaveK

The light in the luggage compartment is a common cause - the switches are rubbish, and the light may be staying on even when it's shut.

But - I can't think of much that would drain a battery in 10 mins! Are you sure it was the battery which stopped it cranking? Wouldn't expect it to work again straight after connection if it was.

I suggest you measure current drain at the battery. If it is high - then pull fuses one by one to isolate the circuit which causes it.

investlt

Have you installed a new stereo recently? Could be a ground loop.

vove

Apparently it didn't drain my battery in ten minutes because after disconnecting and waiting for about five minutes, I reconnected the same battery and she fired right up.

Nope, I haven't installed anything new except for the chip.

fore!

I've been thro a new battery every year for the last 3 years. It appears that our cars can be quirky.

Evidently the best battery for our cars is the optima red 75/35

Good luck

vove

That doesn't sound right, before this incident, I had my old battery in there for atleast two years of usage before it went out.

Greg_L

Vove,

I had a battery drain issue, and i followed Adrians test method and found the drain . It took about 10 mins .
Basically you hook up a multimeter between the +ve batt term and the +ve batt lead .
Anything above 20ma and you have a drain. mine was 50ma. Then start pulling fuses and watch for a current drop. Mine was the interior fan (fuse 1? - i had started at fuse 40, of course), as soon as i pulled it the current dropped to 16ma.

Search the list for Adrians proper instructions, they work like a charm

andrew911

I had drain from fuse 1 as well- turned out to be my climate control unit, which I had rebuilt at otto's of Venice. Now, car can sit several weeks, and starts right up with no problems...just like my old '87 911 used to. In the winter when the car will sit for more than a month, I use the Porsche Battery Maintainer...

vove

Greg_L, I going to try to locate the culprit with the methods you mention.

_Thanks all.

Lorenfb

As mentioned, you need to put an ampmeter on the car and determine magnitude
of the drain. You need less than 100 milliamps for a reasonable battery life without
starting (ideally less than 50 ma).