Forgive me if this topic has been beaten to death...

I purchased and installed a rebuilt alternator to replace the original 24 year-old Bosch alternator. That one had little trouble handling heavy simultaneous electrical demands (according to my volt meter) such as headlights, blower, brake lights and heated seats while the engine was idling.

The newer alternator shows a significant voltage drop under the same load at idle, with the volt meter near the lower red zone. The dash lights do not come on or glow. Revving the engine pushes the voltage back to healthier levels.

The voltage also drops quite a bit when reverse is engaged. (It's the M46 manual tranny.) Do those filament reverse lights use that much power?

The voltage level is just fine under normal driving conditions under light or moderate electrical loads.

I also replaced the battery at the same time with one that has a lower CCA rating and reserve voltage as well. Would that make a difference while the car was running?

New battery cables were also installed. All connections were cleaned and had dielectric grease applied. A new Bosch regulator was placed on the rebuilt alternator as well.

Is the rebuilt alternator a lower amperage than the original Bosch?

Any info would be appreciated since winter is coming and I want to know if I have enough juice to get me through the cold. Below is a pic of the original Bosch alternator on the left, with the rebuilt one on the right:

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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