Alternator Replacement

[johnmurray]

My boat is an Albin 30FC (nearly identical to the 28) with a Yanmar 6 cylinder engine. I purchased the boat new in 2005 and have been trouble free for the last 15 years. My boat was built in 2004 (hull#115). This summer the alternator failed, and after bench testing was deemed not worth rebilding and a new one was supplied.
Unfortunately the new one did not charge the batteries properly (or at all) and the marina owner dtermined that it did have enough power and the replacement should have a capacity of at least 130 amps and "the more the better". (I don't know what the amperage was in the alternator that came with the boat, and that alternator has gone with the trash.I discover in my research so far that Yanmar does not make alternators so boat owners can expect a variety of alternators in boats with Yanmar engines.
My boat is now hauled for the season (winter comes soon up here) so I have some time for alternator shopping and I would appreciate any advice possible. John Murray, Albin 30 FC "katie G" Ottawa Ontario Canada

[dkirsop]

Have your batteries checked and make sure they are capable of holding a charge. If your previous alternator was faulty it is possible the batteries have deteriorated from lack of full charge over a long time. This requires a load test on the batteries as voltage alone will not determine the ability of the battery to hold a charge.

Also, if your alternator uses an internal automotive regulator consider converting it over to a multi-stage external regulator for marine use. This will ensure your batteries receive a full charge after every cycle, something an automotive regulator cannot do.

[Norseman]

Alternator on my Yanmar 6LP is 80 amps, plenty for our purposes.
Relatively small battery bank @ 2 Golf Cart batteries (6 volt) and a group 27 Start battery.