Understanding the Three-Stage Regulator

Came across an article over at SailNet on ‘standard’ and ‘smart’ alternators. Might be of interest to you if you still have your regular automotive alternator installed…
“How does the performance of a standard regulator compare to that of a three-stage regulator? Not very well if the regulator is an automotive unit with a cut-out voltage around 13.8 volts. A 13.8-volt regulator may be satisfactory on a powerboat, but it does a lousy job of charging sailboat batteries. Raising the battery charge level from 50 percent to 90 percent with a 13.8-volt charging source takes more than five hours. Few of us can stand to run the engine at anchor for that long, so unless there is an alternative charging source, the batteries get fully charged only when the boat is under power for a long period. The rest of the time the batteries remain undercharged. The inevitable result is a condition known as sulfation, which is the number one cause of battery death.”