We often get asked how to fit an external regulator to our engines. There are many differant makes and types. Some , like the Adverc controller just need a sense wire from the alternator, others like the Balmar need the internal regulator removed and replacing by a brush box. Here is a well put together description of how to fit the brush box. This is written by Bob Benner who is cruising on his Cabo Rico 38. Here is a link to his blog  

http://bennersadrift.blogspot.com/2011/04/modding-iskra-100-amp-alternator.html

Stanley