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I purchased a 1997 porsche 993 cabriolet two to three years ago but have not been able to drive it because the battery continues to drain. We had a porsche mechanic look at it. His only solution was to add a shut off switch. Unfortunately, this did not resolve my problem. I have gone through several batteries and had to purchase a battery charger. The car has about 12,000 miles on it and just sits in my garage. Help!!

porschemikeandnancy

You don't say how much you actually drive the car. All modern cars have some drain on the battery. My own 993 has never been "sitting" long enough for the battery to run down, but I'd guess about 10-14 days would do it.

Also, when you start it up, just driving it a few miles will not recharge the battery. You need to run it perhaps for a half hour to fully re-charge it back up.

If you have a significant current drain - you will have to find it. Most competent independend Porsche shops should be able to do so. When they put an ammeter on a "shut off" car - they can measure the drain. I don't have ths specs handy, but a few millamperes is probably what it will draw when shut off.

Perhaps another poster knows the correct draw amount when shut off.

ilko

Your best option is to get a voltmeter and start with the fuses. Check if you're getting power on them and if so, trace it. You'll find the culprit.

Does the car have an aftermarket amp or stereo? In many cases an incorrectly installed sound system can cause a battery drain.

Best of luck!

P-daddy

Sounds like you don't drive it very much. These cars will drain the battery if left not driven in 3-4 week time frame. I would hook up a 2 amp trickle charger to maintain a fresh battery. If you only drive once every couple months, just disconnect the battery.

NC TRACKRAT

May I suggest you use the "search" engine on this forum? You'll find innumerable similar posts with very explicit instructions for how to diagnose these electrical gremlins. Usually, as mentioned above, it's something simple like an incorrectly installed amp that's not shutting off, a glove compartment light switch, hood or engine compartment light switch. If you can't find a competent mechanic to do this, then go to an electronics shop or Radio Shack, buy a good, digital VOM/ammeter and have them teach you how to use it. You WILL find the problem and cure it!

chris walrod

Common drain sources include faulty CCU's, dome lights, trunk switches. Also factory installed radio's have been known to draw a lot of current.

Stealth 993

SO you use the battery cut off, & the battery still dies? How long does this take? How often do you drive the car? You are replacing the batteries when this happens? Have you checked to see what the current draw is when the car is off?

Just about all 993's will have a dead battery after sitting around a month or so. The easiest thing is to just get a simple trickle charger. I have a Ctec one that plugs into the cigarette lighter.

AOW162435

Welcome to Rennlist...


Andreas

IXLR8

So what current drain did he measure, or did he even do that?

About 22 mA is normal.

With your luggage compartment light "off" by manually closing the latch, take your negative battery lead off and insert a DMM set to 10A DC , then to 200 mA DC and find out what the drain is.

If it is more than roughly 22 mA, start pulling fuses one at a time and see which one makes a difference. Troubleshoot from there.

BSL

It is interesting to see the reports that 2 weeks can cause the battery to drain enough that the car won't start. The first winter I had my car stored I was able to start it without hesitation after over a month and a half (shortly thereafter I did put a battery maintainer on it though).

gaby1088

step 1: replace battery
then do everything else that the above posters said.

Denise993

I had a terrible drain problem. I couldn't let it sit for one day without jump starting the car. The trickle charger couldn't overcome the drain.

My mechanic traced it back to my climate control unit. I had my mechanic disconnect it and the drain stopped. Then I sent the unit to these guys (no affiliation) and got it back ... bingo! ... no drain.

http://www.autoecu.com/

IXLR8

I know that sounds easy, but I wouldn't.

I'd want to check to see what the issue is first.

gaby1088

what happens if the issue is the battery? hes gonna go nuts trying to figure out what it could be. Its an older battery or it may be defective.

IXLR8

It appears to be, especially having gone through several batteries in two or three years. That many batteries would last me more than 84 years.

Except I wouldn't be replacing them without charging and testing them first.