Alameda996

So I don't think it's the battery. I swapped out the old Boxster size battery for a new one of the appropriate size.

Curious what people think of the following (a) current assessment, and (b) proposed solution:

1. Assessment

Voltage still drops after the car gets warm, though not as much as with the older battery. My mechanic said he drove the car 10 miles or so then checked voltage drop, and didn't see any, but that's because he didn't get it warm enough. Having read a bunch of message boards it seems when others have had this problem (and others have said this heat-related voltage drop is a not-uncommon problem in 996s, even 997s...) it is a result of a bad alternator cable (from alternator to starter) or bad voltage regulator. And even a bad "ground strap".

2. Proposed solution

I'm going to swap out the alternator cable and the voltage regulator. If i can figure out what a "ground strap" is, i'll do that too!

Will post what happens



http://www.renntech.org/forums/topic...e-low-voltage/

kromdom

As you have already considered: bad cable, bad regulator, bad ground strap MAY be culprits too. Any plans to load test the ALTERNATOR NOW/FIRST before swapping out above? Almost all parts stores do this for free.

P.S. My 2 cents (more for future reference): battery and alternator could (should?) have been tested at the same time as THE first course of action.

JohnCA58

I agree, most battery testers have a alternator tester with a carbon pile to load the alternator and check the amp output. I believe the 996 output is 120 amps. should be capable of 110 amps at 1200 rpm's.

DBJoe996

Look in front of your right rear wheel. There is a large fat wire going from the engine block to the chassis. That is your ground strap.

Alameda996

Yes, alternator and battery were tested.