Do I need to replace my alternator?
 

Do I need to replace my alternator?
I have a walmart Maxx 49 battery that is 1 month old (I'm not noticing any problems).
I went to the Interstate battery store (I have a friend that works there) today to check on my battery.
The voltmeter read 12.8 volts (idling).
When I gave it some gas or turned on my headlights the volts went down to about 12.6 volts.
I was told that the battery should read at least 13 or 14 volts, if not I could have a problem with the alternator.

History...
Aug 16, 2010 - My OEM Moll battery finally died (starting the car was becoming increasingly difficult), so I replaced it with a Walmart Maxx 49 battery (my 2006 997 was initially purchased Oct 2005).

Oct 18, 2010 - My walmart battery was initially strong. My 997 is a daily driver. The first two weeks of October I did not drive my 997 daily. I let it sit for 3-4 days, and then would only drive it a few miles. I began to drive it everyday again. After a few days, I noticed that I was having a hard time starting the car. The battery died and I exchanged my walmart battery for a new Maxx 49 battery (hoping it was a defective battery).

I called my friend who is a service tech at a porsche dealer, and he said I should be ok. I plan on having him check out the car in a week.
What do you guys think?
Thank you in advance.

It could be the cable from the alternator. There was a known problem for 2006 and I believe a TSB.

Thanks dndodd.
I will ask about the TSB.

According to the indy that performed the PPI on my 05, a number of cars had factory issues with the wiring harness/connectors to the alternator. The previous owner had the work done after experiencing issues similar to yours within the first year at no cost and Porsche even replaced the alternator. Perhaps Porsche will fix your issues at zero charge being 5 years out. Good luck.

I just got back from the dealer and had my car checked out.
It's the cable from the alternator that is causing weak starts and increased battery drain.
There's a TSB (bulletin) for this issue, but since my car is 5 years old, the dealer will not cover it.
I'm getting charged $700 for parts and labor.
Thanks for the reply Sharkys.

If it was me I would be raising an issue with Porsche. It is a known problem.

Thanks dndodd.
I asked my service tech, and he is going to speak with the service manager.
I'll keep you posted.

What they will or did do:

Check Battery ($86.95 + $31.00 misc)
Check Voltage Drop charging circuit ($62.00)
Remove and Replace Alternator ($139.59)
Remove and Replace Intake Distributor ($46.50)
Replace Battery Cable from Alt/Start ($263.50)

Some Indys can replace without have to R&R a few of those components however. Good Luck - this really should be covered by PNA. My cable was replaced after 3.5 years/21.4K miles (I incorrectly stated it was replaced at 1 year previously) and I'm sure there are thousands of these work orders in their system particularily OPCODE 97451999 - which is the last item. Good luck.

The dealer said they would not cover it because I was out of warranty.
I was told that the cable was crimped which didn't allow the alternator to fully charge the battery.
I took a look at the old cable, the plastic covering had melted onto the cable.
The cable was $200, and $500 for labor.
This morning the voltmeter read 12.7 (idling).
After the new cable, the voltmeter read 14.0 (idling).
Thanks Sharkys and dndodd.

How badly was it crimped? I just replaced the alternator on my 996 Turbo after similar issues traced to other, incorrect issues including a bad battery.

It just took a couple thousand more miles and the alternator failed, making me call for a tow.

Hard to say how badly it was crimped.
Bad enough that there was some type of power loss from the alternator to the battery.
All the info I have is according to what my service tech said (who is my friend's brother).
Good luck teflon.

I bought an extended warranty so it only cost me $300 to get it replaced. $100 deductible plus $200 for the battery, which they wouldn't cover.

$20 tip for the tow, otherwise paid for by AAA. I have 4 cars and tend to do a lot of mods so $85 or whatever for AAA is well worth it. I've had them come pick up a car out of my driveway that I've gotten sick of completing some complex mod on and just take it to a shop to finish. Good deal.

I am having my cable replaced and should get my car back from my indy tomorrow morning. As soon as I can, I'll post how much he charged me but I am expecting <$350 plus tax... crossing my fingers.

My actual repair came out to $283 including tax. Not bad I guess but, if it is a known problem so that a TSB has been issued, they should in good faith take care of it on one's behalf. I took it to my trusted indy as he's always been reasonable in his pricing.

Wow, that is a good price.
I was charged $700 (friend price).
I called Downtown LA Porsche and the service advisor quoted approx $1800 (they also said that they wouldn't cover the cable because the car is 5 yrs old and is not under warranty).
There is a TSB, but there is no recall.
I thought I got a good deal, but after hearing that you had your cable replaced for $283 makes me feel a bit unsatisfied.