Alternator Upgrade

[Beneteau 321]

Looking to upgrade our original 55A alternator to a high output alternator.
The question is (have calculated we require 120A)
(Yanmar 3GM30F in a 1997 Beneteau 321)
1)Make of alternator
2)Internal or external regulator (AGM battery bank)
3)Upgrade to serpintine belt system or keep V belt
4)Any issues doing this upgrade

 

[cymeyer]

Why do you need to upgrade the alternator? Ours seems fine, but I would not know the difference. Presume your belts are good and properly tightened?

 

[Maine Sail]

The question is (have calculated we require 120A)

Is this the "hot" output, meaning you need 120A when the alt has warmed up? If you need 120A hot running then you'll want a 140-150A alternator.

(Yanmar 3GM30F in a 1997 Beneteau 321)
1)Make of alternator

Balmar or Electromaax: If you need an alt that big you will need a serpentine kit or will need to down rate the alt to 80-90A in belt manager with the external regulator. Both Electromaax and Balmar offer serpentine kits for their alts and Yanmar engines.

2)Internal or external regulator (AGM battery bank)

External (Balmar MC-614 or ARS-5 ) with alt and battery temp compensation.

3)Upgrade to serpintine belt system or keep V belt

If you keep the v-belt then I would not suggest pushing the alt beyond 80-90A. Do buy the bigger alt and you can do the serpentine kit at a later date. You'll just de-rate the alt to 80-90A in "belt manager" until you get the serpentine kit.

4)Any issues doing this upgrade

Other than cost, not at all.... These do need to be properly installed and the alt circuit should ideally be direct fed to the house bank with proper fusing.

 

[Stu Jackson]

Maine Sail's advice is right on. Here's some info on running your alternator output to your house bank. Your Beneteau wiring is most likely different than most boats with 1-2-B switches, since you probably have the two red and one black switches in your aft cabin.

Basic Battery Wiring Diagrams This is a very good basic primer for boat system wiring: http://c34.org/bbs/index.php/topic,6604.0.html

This is another very good basic primer for boat system wiring: The 1-2-B Switch by Maine Sail (brings together a lot of what this subject is all about)
http://forums.catalina.sailboatowners.com/showthread.php?t=137615

Under the Forums tab, go to Featured Contributors, then Musing with Maine Sail and read up on some of his many helpful posts. Some are included in my "Electrical 101" topic, here: http://c34.org/bbs/index.php/topic,5977.0.html

 

[Ralph Johnstone]

Why Not do it in Stages ..................

2)Internal or external regulator (AGM battery bank)

.................... by starting out with installing an external regulator.

We installed a Balmar ARS-5 for our 55 amp alternator on a Yanmar 2GM 20F and finally started pumping some real amperage into the batteries. The original internal regulator was set to 14.2V and spent most of its time dribbling out about 8-10 amps. Never got above 80% SOC no matter how long we motored for.

The new Balmar has a max of 14.7V on bulk and steadily puts out about 35 amps. I now get 100% SOC after a good day's motoring.

I didn't think a B321 could even carry enough batteries to accept 120A charging .

 

[PDReynolds]

I agree with the statement about the battery bank. I looked into this for my B423 and from my calculations I would need to install twice the battery capacity to accept the charge from a Balmar 120Amp alternator. My stock 60 amp alternator with my Yanmar puts out nearly 50 amp when the batteries are between 50 - 75 state of charge. I am running 380 amp hour capacity for house batteries. and a dedicated starting battery.