My Navy son has been relocated, and has left me with his '87 944S to keep in the garage. Even before he left he was having trouble with the battery dying after sitting just a while. Just before he left he had the car serviced by a well known local Porsche mechanic who installed another new Interstate battery. I put in on a trickle charger until yesterday when I tried to start it and nothing...getting 5 volts!! out of the battery connected and disconnected. I've been trying to charge it again but my trickle charger won't break throught the sulfation so I'm going to get it supercharged tomorrow.

He's ticked off and frustrated, and 6000 miles away. There's gotta be a short somewhere. Are there any issues within the model that are known to cause shorts or battery drain? I'm not sure where to start or how to trouble shoot where the problem is. Sure the car will start and run well after a jump, but when it sits it just dies.

Any ideas?

Thanks guys.

NYNick

How long is sitting "just for a while" exactly? And exactly what problem(s) was he having then? Did the start of them coincide with anything in particular, especially putting in a new battery?

Is the battery the correct size and type for the car? Or just some random battery that was picked because it fit the spot in the car? Are there any aftermarket components in the car that draw electrical power? What brand/type of trickle charger is being used? Are you sure it works correctly, or could it be broken (i.e. have you ever tested it on a volt/ammeter)?

Is the car kept in a heated garage, or one that gets very hot? That greatly increases both the rates of sulfation and discharge. What do you mean you're going to get it "supercharged?" Just putting an excessive voltage through it is not the right way to solve a sulfation problem and you might as well just throw this battery away and get a new one if that's how you're proposing to try and fix the battery.