I have a new rebuilt alternator in my 240 that I think is a 100 amp unit. (See this thread for more info: http://www.brickboard.com/RWD/index.htm?id=1278071&show_all=1 ) It was working fine until recently when I placed a heavy load on the electrical system (headlights, blower, two seat heaters, brake lights). At that moment while the engine was idling, my volt meter plunged from about 14 volts to just outside the lower red zone. (The voltage went back up upon acceleration.) This was unexpected since I assumed that this new 100 amp alternator was more powerful than the old one, which never had a problem of handling similar loads.

In addition to the newer alternator, I also placed a new Bosch regulator, battery cables and battery into the car, so I wasn't expecting any electrical maladies for quite some time.

Should I have this alternator checked by someone? I still have the original one, which I could have rebuilt and reinstalled into the car.

Any other ideas? Thanks.
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Mike F - 1984 244 DL - 265,000 miles
Original engine, transmission, drive train, alternator, starter
Undergoing reconstructive surgery with POR-15