Alternator/Regulator Mods

Alternator/Regulator Mods
Jim Norman, Jos Sonneville
Hull #:     33


We’ve had a lot of “traffic” on our Sailnet email discussion list on this topic. Modification of your engine’s alternator, to provide connection for a “smart” external regulator, can make the full alternator output available for your battery charging; otherwise, the typical alternator’s regulator will provide only about 1/2 of the available charging current.

The particular description here is applicable to the earlier C380’s that have the Westerbeke 42B engine, which includes a 72-amp alternator. The same concept will work for the Yanmar-equipped boats, although it’s smaller 55-amp alternator has less potential “reward”.

The alternator’s standard regulator is contained in a housing [aka: “doghouse”] attached to the back of the alternator. There are both “N” [negative] and “P” [positive] types, so named because of the electrical location of the regulator with respect to the alternator’s field winding. They require

You need to be logged in to see the rest of this content.  Catalina380-IA members, please login.

To join please fill out a membership application (Association->Membership Application) and send a check to the address on the form.

Leave a Reply

This site uses Akismet to reduce spam. Learn how your comment data is processed.