Paul Guatney wrote:

Hello all!

I don't know if this is the appropriate group to ask a marine
engine/electrical question

Prob'ly not



I have this ancient Island Trader 41 ketch that I am rebuilding,
replacing, sometimes just repainting, her old equipment. I am at the
alternator. It is a "Battery Master BM-140" by Smythe Miller Marine
Inc. of Oviedo, Florida. ...... Do I need
to replace the regualtor?

You'll definitely want to replace the alternator at some point, but the
real question is, "Is it time now, or can I get along for a few years on
the old one?" The rebuild shop should have tested the output voltage &
amperage, and have that data to give you. If not, you can test it
yourself.

Hook up the alternator to two paralleled batteries, with switches to cut
them in or out. One should be close to dead and one fully charged. Making
sure to always keep a load on the alternator (never switch off both
batteries at once) run the engine & put the alternator to the dead
battery. See what the amperage and voltage is, if you have the time let it
run long enough to put some charge in it & see if the amperage responds as
the voltage climbs. Then switch in the charged battery, and see what the
volts & amps do. Then switch off the dead battery. The voltage and
amperage should follow an inverse curve, with the voltage never going
higher than 14.2 when amps reach a trickle.

A word of advice- newfangled hi-tech 'smart chargers' are well worth the
money, even if you are getting by on cheapo golf cart batteries. Study up
on 12V electricity, it will be some of the most valuable knowledge a
cruising sailor can have.

Anybody got Sea Hags web site link to send this guy?

Fresh Breezes- Doug King