Put in new optima red top in my 993 in December. started right up over a two week period. put on a porsche lighter charger .didn't try it for almost two months now. dead again.. any ideas how this can happen . have had an optima in a 356 for years without problems..

 

Could be a bad battery, it happens, not all batteries, even from the same manufacturer are the same, that is why they have dated warranties and there are schedules to prorate their value. I would take it back to where you purchased and exchange it.
On the other hand, you could have a electrical problem, but I would look at the battery first.

 

The security (alarm) unit in the 993 seems to be quite a power hungry beast. I have the same issues, and I gather all of us have. I seem to remember there's a procedure for locking the car without the alarm system activating, involving using the interior lock button from the passengers side, but my recollections are a bit sketchy at best. Maybe you could try this.
My experiences with Optima's aren't err...optimal.

Peter R.

 

If you are referring to a charger that you plug into the cigarette lighter, I don't think they work for our cars. My understanding is that the cigarette lighter needs to be working when you try to charge it, and ours don't have power when we take the keys out. If you left your ignition on, it may work, but I wouldn't want to leave my car charging in this state!

 

My 993 does have power to the lighter when switched off !

Peter R.

 

Same here.

A very basic way to see where the draw MIGHT be coming from is take a blown fuse and insert it one at a time in all the fuse positions and use a DVM set to mA's and track which fuse locations have a draw and how much that draw is. I don't think this will work if the draw is through a relay (depending on the circuit).

You need a blown fuse because you must test amp draw in series and that can be done by putting the test probe tips on the top exposed pins of the blown fuse.

(My DVM probe tips won't fit down in the fuse slots to make a connection which is why I use a blown fuse)

 

I have the same problem in my current (1995) and former (1996) 993. The optima goes dead after about 3 weeks of non-use. Pretty darned annoying. I have an aftermarket alarm on my 1995 instead of the factory immobilizer/ keyless entry system on later 993's.

 

My batteries in my 1997TT would decline after a few weeks even with the optima. i bought a porsche lighter socket maintainer and its been perfect ever since.

 

I've had a OEM battery with the Porsche cigarette lighter charger for over 2 years now.
Sometimes the car sits for 3-4 weeks at a time, w/o any starting problems.

 

You shouldn't be seeing more than 16-30mA in total current draw. If the current draw is over 500mA it is probably a switch (doors, trunk, etc.) and if it is over 100mA it will probably be caused by a relay. The CCU will also have a high draw for upto 20 minutes after you turn off the ignition. The type 993 are starting to see the exact same problems the 964 saw at around 10 years of age. So the first thing to check for are sticking trunk (front/rear) and door switches.


To test for a sticking relay you;

1. Switch the igntion on and off, remove the key and close the door.
2. Install multimeter between the battery minus pole and vehicle body. Then disconnect the vehicle ground strap at the body mounting point. This will prevent interrupting the circuit and allowing the relay to collapse.
3. start pulling relays individually.

and instead of pulling relays you can pull fuses to check the related components.

Porsche even warns in a TSB (Diagnosing Discharged Battery, March 29, 1994) not to directly probe the fuse contacts so you don't spread them.

 

I have to say all these years reading on this forum, most if not all the baterry related problems posted were just Optimas. Aren't they supposed to be good?

 

Thanks, Jason.
It figures, the one time I was doing something right it was by accident!

 

Must be a UK/Euro thing. Mine doesn't have any power if the ignition is off.

 

be sure the lighter socket is even still wired. If the radio has been out it is easy to knock the wire off the back and a PITA to hook it back up!

 

I also had big problems with my battery. But I found a simmple solution ;-) which switches off the alarm but takes care about the battery. And nobody will be able to start the car either. See link.
http://www.automotion.com/productpag...ery+Disconnect