Old Stock Alternator - New 3 Stage Regulator

[Stu Jackson]

Has anybody done this?  Put a newer three stage regulator on an old stock 55 amp Motorola alternator?  

Or do you have to get a new alternator with no internal regulation?

[tandm]

My boat has a three stage with the original alternator.  It was done by the previous owner so I can't speak to the details.  I have not had any battery related problems since I purchased the boat.  The only battery related change I have made is the upgrade to a Statpower 20.

td
Peregrine #543

[jentine]

I believe that you would have to disable the internal regulator first.  It is inconceivable that the new regulator could fool the internal regulator into seeing a need to produce more electricity than is necessary.  Two regualtors in series is counterproductive.
Jim Kane

[tandm]

Yes, I believe you do.  My is anyway.

td
Peregrine #543

[Stu Jackson]

Ron

Doing this for a friend who bought a new regulator and wants to wait to upgrade the alternator.  Short term, but his choice.

I assume that by "disconnecting" the old internal regulator, you simply mean taking the wires off the alternator posts from the "slapped on the back of the alternator" old regulator.  And, of course, protecting the old ring terminals of the old wires.

Mexico's sounding really good right now....

[kntclark]

Stu, I modified my stock alternator about a year ago and added a Heart three stage regulator.  It worked fine for a few months until I came across a deal on a used Balmar 100 amp alternator that I'm using now.  I keep the stock alterntor on board as a backup.  

The change involved disconnecting the internal regulator and changing the wiring to modify the regulator from a p-type to an n-type, if I remember correctly.  I think I had to cut the lead to one of the brushes and solder an extension wire to it, but it wasn't too difficult.  I wanted to make the change so I could put the internal regulator back as a backup in case the external regulator failed.

I think the main risk is the stock alternator could overheat if driven to capacity for too long by the external regulator - the internal regulator doesn't let it reach a high enough voltage to overheat (or fully charge the batteries, either).  If you want, I can try to find my notes and give you some more details.

Terry Clark
Yet To Be #1095

[jentine]

A little research goes a long way.  Look at some of the other web sites concerning alternators.  Balmar would lead us to believe that they are the great seer for recharging batteries.  I use an alternator that I got in Florida several years ago and it does the trick.  Look at http://www.thefloridakeys.com/batteryshack/  for a much reduced price and a great warranty.
Jim Kane