Hey guys!

Riddle me this:

So, I recently replaced my Porsche Moll battery with a brand new Interstate MTP-94RH7 (05/10/12). I did the installation myself and everything worked beautifully. Started strong. No problems, whatsoever.

Today, I tried to start up it up and it didn't turn over. Completely dead. Mind you, this battery is less than 30 days old from it's purchase date (Battery was manufactured in April).

Any ideas as to why this is an ongoing issue? Within the last 4 years, I've had to replace my battery 4 times. FYI, I have an aftermarket Alpine audio system with an amp directly connected to the positive battery terminal. I really don't see why this would be an issue considering others members here report to have aftermarket audio components on their car. They say they don't operate the car for week/two weeks and it fires up no problem. Not even plugged in with a maintainer or anything. How is this even possible? My car starts to hesitate if it hasn't been driven in more than five days..

Before it gets mentioned, I do drive this car everyday except on the weekends. It only sits for two days. And I do lock the car after every usage. It doesn't beep once notifying me of any lights, doors, trunk open etc. It silently locks the car without any issue. Had the Porsche OEM Moll for almost two years before it gave out.

Could it be a short? Bad alternator? Ignition switch? Starter? Terminal cables? I'm hitting a proverbial brick wall. Any thoughts on this?

 

It's the same problem that existed prior to the battery install. You'll have to find a live or dead short which is causing your drain. Changing the battery continuously is an exercise in futility. You need to find the short. I leave my car up to a month at a time and never any sign of weakness.

 

I don't have a meter to find the short myself. I'm really thinking of taking it to the dealership, but I know it'll cost a pretty penny. Any ideas besides bringing it to the stealers?

And a month!? Do you have any aftermarket setups??

 

start your car, with the engine running, what does the voltage read? should be around 13.5-14v. if not, it's the alternator.

i suspect your issue is the stereo causing a drain. i would go to another stereo shop to have them check the current draw from the battery.

 

I think the factory set-up is not sufficient to keep the battery in good condition. I had to replace the battery when I bought the car a couple of years ago. I recently had to replace the battery again, so I replaced the alternator as well. Now, I charge the battery on a charger once a week to keep it at full power. There appears to be a programmed charge going on when the car is running. On a cold start, the charger goes to full for about 10 minutes then slowly drops off until it is hardly charging at all. Subsequent drives during the same day will never cause the charging to go to maximum again - until the next cold start the next day.

 

You definitely have a drain somewhere that you need to find.Why don't you disconnect your stereo system for a week and see if that is the problem. That could be your number one step IF that is the only NON- OEM power hog that is installed. I would do that before hunting for anything else. You may also feel / touch the amplifier and see if it is warm or hot in the morning. If it is not sucking power it should be cold. But that is the system I would look at first.
Keep us posted.

 

??? The factory set-up was engineered to keep the battery fine. I've only owned three Porsches but I've never had a dead battery and I leave my car when I'm out of town working for up to two months at least. It sounds like your system does need attention.

 

A commonly overlooked drain will be the alarm system. These are often tripped during or after a battery dies and is never reset. I believe they they must be reset with a durametric scanner.

 

I feel your fustration. I had the same issue about 4 months ago. The car would start right up during the week while being used but if left sitting for more than 10 hours over night or if not used in the weekend the battery was dead. I pulled every fuse and bulb in the car to make sure there was not a short and 4 batteries later I decided to do more research. I read a forum where the diode on the alternator goes bad and that starts to cause a drain when your car sits and killing your battery. This is bad because then you cant open your hood since the latch is also electric. I became an expert opening my hood through my wheel well. It was the alternator after all. I had it replaced and had not had an issue with a dead battery again

 

any luck on finding the culprit that is draining your battery?