Failing Voltage Regulator

My experience was with my MY03 Boxster. Because I have a Carrera instrument cluster, I have the voltmeter. For the past week or so, I noticed the voltage dropping - sometimes as low as 10.5 volts indicated - as I drove along. At the point that the maximum voltage (after the car sat overnight and following a start) never exceeded 12 volts, I measured alternator voltage with a digital voltmeter. The cool alternator voltage was now barely 11.5 volts.

Suspecting the voltage regulator, I dropped the car off at the dealer. The technician confirmed only that the alternator was not charging properly. Seeing how the cost of a new alternator is in excess of $1100 and there is no "official" protocol for repairing bad alternators, I asked the technician to remove the alternator so I could take it to a repair facility in the neighborhood. Even if the alternator was itself faulty, I would have had the chance to have it repaired. The long and the short of the story is that I had a repair facility replace the (indeed) bad voltage regulator and had the technician reinstall the alternator. The bill for the entire job was $84 for the alternator repair and two hours shop time (less a 10% PCA discount) for a total of about $290. I know I could have done the operation myself, saving ~$250, but I elected to have the dealer do it, thus keeping a maintenance paper trail.

While not a primary scan instrument, the voltmeter should be eye-balled periodically to see if any bad trends are developing. A failing voltage regulator could explain why some people go through batteries quickly. For Boxster owners who would like to monitor their charging system, Pedro's Garage sells a voltmeter kit:

[www.pedrosgarage.com]

The display is mounted on the fuse panel cover. I have no affiliation with Pedro's Garage, nor am I a customer....yet.

Bill