I was driving the tt so i could stretch her legs on a nice beautiful day in houston. After about 30-40 minutes of mixed driving, the psm light went off. I looked at the battery charge and it showed barely above 10. SO I immediately drove home, stuck her on a trickle charger overnight and the next 24 hours charger showed 100%.

So few days later I drove it to pick up my son from school, after about 1 mile or 5 minutes, i noticed the battery slowly drifted downward towards 12. turned ac on and it dipped below 12. nervously I rushed to pick him up another 5 minutes away.

When I got back in the car, it showed aprox 13.5. I thought to my self how strange.

Is this normal? does anyone else experience this? Do you mind looking at yours and posting up your results for comparison.

Thanks a bunch

 

I've just has what sounds like exactly the same problem with my 05my 996t
When started from cold I had about 13.8v at battery but after 20 mins or so it dropped to about 12v,this meant the battery wasn't staying fully charged and the only way to make sure it started next time, was to keep it on a charger all the time.

It turned out to be the voltage regulator,check out my replies in this thread

https://www.6speedonline.com/forums/...y-issue-4.html

My porsche dealer wanted £1100 to supply and fit new alternator

My porsche indy wanted £500 to supply and fit a recon alternator

I sourced a new voltage regulator for £26 off Ebay ( its bolted to the rear of the alternator) and fitted it myself and its worked perfectly since

here is a alternator diy thread
https://www.6speedonline.com/forums/...e-replace.html

Since I replaced the voltage regulator I haven't had to put it on charge and its started perfectly, I don't feel worried that it won't start anymore.
By the way the previous owner replaced the battery twice and the startermotor in the six months before I bought it. I think he was trying to fix this problem

Hope this helps

Andy

 

thanks i am going to try it.

Is it recommended that I disconnect battery for trick charging? Because that is what I did. The reason is the light in the front bonnet and the engine compartment light stayed on when I was charging the car. That was annoying to tsay the least, hence, I disconnected it.

Now, radio is out because of the code.

Man I have so little time

 

Just to add to the excellent DIY from And996TT, here is some DIY for the regulator itself. Just did mine and it is a very easy job...

http://forums.pelicanparts.com/porsc...placement.html

http://forums.rennlist.com/rennforum...d-alt-reg.html

 

No you do not need to disconnect the battery to trickle charge it. Just dont be tempted to put it on boost charge.
I keep my 996tt on battery maintenance charge all the time. I charge via the cigarette lighter socket so dont have to open the bonnet/hood
Frank

 

The luggage and engine compartments have switches which automatically turn the lights on whenever the lids are open. I loosely shut the lids over the battery charger cables in order to close the light switch.

 

Thanks for sharing that site with me. I wish I had time to drive the cars more, hence avoid this sometimes annoying events.

 

I decided that i would just leave the trickle charger on 2 amps like i do the 964 3.8.

Electricity is getting expensive.

 

I flattened out the cables so they wouldnt touch the hood. then i looked inside the bonnet to see if the lights were still on and of course they were. Small price to pay for a charged battery.

I felt like a kid, looking to see if the refrigerator lights would stay on after i closed the door.

 

Ok, I stand corrected! Pretty close tolerances on those switches, eh?

 

You can always disconect the light if it is not turning off. It pops right out and you can unplug the light. That's the easiest solution

 

No one with a 996 should have the interior light staying on. There is no switch in the hood for the light. Its all controlled via the Alarm/Central locking unit. When you unlock the car or pull up a door handle the light goes on then is timed to go off. So long as you lock the car once you have the charger on and the hood is fully closed then the Alarm/Central locking unit will switch off the interior lights once the car is locked.
So no one should be having the old fashioned problem of door and hood switched keeping interior lights and courtesy light being left on!

Frank

 

I like to leave the hood open when its on trickle charge just as a reminder to make sure I don't reverse out the garage with it still connected.

To make sure the luggage compartment lamp is off I close the switch with a screwdriver.

Also if you just pop out the luggage compartment lamp, the glovebox lamp and the engine compartment lamp will still be on, they are all part of the same system, hence why I close the switch.

By the way SunnysideBB it was because of your posts from when you had your alternator problem that I was able to fix my car so cheaply, so thanks for that. Its this type of info sharing that makes these forums so great , I just need you to come up with a £25 cure for IMS noise now and all would be right with the world

Andy

 

Cheers Andy,
Nice of you to say so.
I wish i had an easy repair for IMS noises as i would make a fortune.lol

Frank

 

Sorry for the bad information, I think I will listen and keep my mouth shut!