Battery/alternator

[me-tm]

I'll post in here instead of starting a new thread.

I think the alternator on my HDi is on the way out. I put a new battery in back in October, a 640A beasty, but for the first few miles of a drive in the dark, the headlights go slightly dim (and the instrument binnacle lights, and the heater blower slows down) whenever I lift off the throttle. Once the car is up to temp it all behaves itself again though.

Thoughts on this?

I never thought to try a multimeter on it yet. Derp. It never, ever struggles to start though.