Alternator regulation

[rogerclaydon]

I have a Dufour 425 with a D2-55 Volvo Penta diesel. I purchased it new 3 years ago.
This comes with a 115A alternator which the brochure says includes a 'charging sensor that measures delivered voltage at the battery bank'.
A simple question is this the equivalent of a smart regulator like a Xantrex or Balmar MC 614?
I assume to add a smarter regulator to the alternator I would have to alter my presumed N type alternator? Is this easy/expensive or will I have to buy a new alternator?
Cheers Roger

[hellosailor]

"A simple question is this the equivalent of a"
No. That's what is called a "3-wire" system as opposed to a cruder "1-wire" system that does not have a charge sense lead. Standard alternators with internal regulators, no matter how smart or dumb they are, pretty much all use a separate lead to sense the battery voltage. Typically, a pulse-width output alternator can turn the main output on/off 100-10,000 times per second, and it looks at the sense lead in between those pulses (while it is producing no power) to determine battery voltage. Low voltage, send more pulses of power. High voltage, send fewer pulses. And the alternator puts out the same voltage level all the time (14.3-14.4) just pulses it differently, more or less frequently as needed.

You don't need to buy a new alternator, any shop can disconnect the internal regulator and bring out a wire to hook up a smarter external regulator. Probably charge you $50-100 to do that.

The only disadvantage of a 3-wire system is that the alternator relies on the feedback fro the voltage sense lead. So if you have two batteries or batteyr banks--you need to make provision to switch the sense lead when you switch batteries.

[Maine Sail]

Originally Posted by rogerclaydon

I have a Dufour 425 with a D2-55 Volvo Penta diesel. I purchased it new 3 years ago.
This comes with a 115A alternator which the brochure says includes a 'charging sensor that measures delivered voltage at the battery bank'.
A simple question is this the equivalent of a smart regulator like a Xantrex or Balmar MC 614?
I assume to add a smarter regulator to the alternator I would have to alter my presumed N type alternator? Is this easy/expensive or will I have to buy a new alternator?
Cheers Roger

What part of a smart regulator are you looking for specifically? Temp sensing, adjustable voltages for GEL or AGM, float level voltages?

You already have a 115 amp alt so you are going to get from 50% to 80% state of charge just as fast as with a "smart" regulator as with your dumb one.

The first thing I would check is your voltage output of the alt. To do this make sure the batts are at 100% state of charge then measure the output voltage at the B+/alt output post. If it is 14.2-14.4V then you are in a pretty good spot for regular wet cell batts. If it puts out 14.6V+, or less than 14.2V a smart regulator can be a wise choice.

Unless you need or want temp sensing or different output voltages for AGM or GEL Cells you will not gain much by going smart if you've already got 14.4V. Other than a float voltage, which IMHO is a pretty much useless feature for an alt on a sail boat unless you motor constantly for hours and hours on end or own a trawler, you may simply dent your wallet and not see much return on the investment.

Smart regulators, in many cases, are not as necessary as the marketing guru's at Balmar would have you believe. If you have AGM or GEL yes smart is good, regular old wet cells, consider keeping what you have if the voltage parameters are good...