I think complex electronic regulators is a step in the wrong direction. The
whole idea of the Manual Alt. Control (MAC) is to override the standard
alternator regulator. Reason being, the standard regulator starts 'tapering
off' long before your battery is fully charged, assuming you will be running
your engine for many hours, as in an automobile. The real world on a sail
boat, you want to charge a large battery bank in short order so you can
secure your engine and enjoy the piece and quiet of sailing or your
anchorage.

The MAC allows you to charge at a higher amperage until you observe the
proper voltage level. It also allows you to raise this voltage for a short
period for the occasional equalization charge. With care all of these
functions can be accomplished with the simplest MAC.

C.Plath, following Edgar Beyn's (author of 12volt Doctor's, etc) designs,
developed the AutoMac and the AutoMac II which gradually became more
complex. This complexity, however allowed semi automatic charging that is
better suited to the needs of a boater with high demand and deep cycle
batteries.

I have been using the AutoMac II for 3 years and it works flawlessly.
However, it will over work a automotive alternator since they aren't capable
of producing their rated output for extended periods of time. Even at 80% of
rated capacity I burned out two this summer. One went from overheated
brushes and the other was due to burned out stator. I think I could have
avoided the latter if I had installed the AutoMac temp sensor on the
alternator case. (lost that some place over the years).

The C.Plath AutoMac and AutoMac II is no longer made and I purchased mine
over 10 years ago but only installed it on this boat 3 years ago. It is much
more complex than the old MAC described in these books. It is solid state
and well built, with mostly automatic function in all charging phases.

Here is a link to the installation and operation manual for the AutoMac II.
http://www.hctc.com/~esteve/INGRID%2...s/cplath~1.pdf

Perhaps you may find one at a swap meet or on eBay. I know I don't want to
sell mine.


--
My experience and opinion, FWIW
--
Steve
s/v Good Intentions