Yanmar & High output alternator

[sinna42]

I am thinking of fitting a high output alternator on my Yanmar 3GM30F in place of the original Hitachi 55A version. Probably something like a Balmar 90-150 which has twin 1/2" pulleys.
Has anybody else tried this by adding an extra pulley on the crankshaft and making a special water pump pulley to suit? I am concerned about the load on the water pump bearing - could it handle it?
I don't have enough space to mount an additional alternator so it has to be a small frame type in place of the existing one !
House bank will be approx 400ah - Lifeline AGM + a smart alternator regulator

Any comments or suggestions would be welcome
Thanks

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[Jools_of_Top_Cat]

How much will you be asking for your 55A alternator?

<hr width=100% size=1>Julian

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[sinna42]

I am going to keep it as a spare !

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[paulrossall]

I think this subject has been covered before on the Yanmar web site. You will probably get a answer if you post on their forum. <A target="_blank" HREF=http://www.yanmarhelp.com>http://www.yanmarhelp.com</A>.
Paul

<hr width=100% size=1>" there is nothing-absolutely nothing-half so much worth doing as simply messing about in boats".

 

[pvb]

Probably overkill...

The Balmar is a fine alternator, but its output is probably much more than you need. Having a 140A alternator doesn't mean you'll be able to push 140A into your battery bank - it depends on the battery bank size and type. With 400Ah of Lifelines, you'll be lucky to see more than 100A charge current, even when they're pretty low. So you'd save yourself a lot of trouble (and expense) by fitting a single-belt alternator (say 90A) instead. Unless, of course, you plan to greatly increase the size of your battery bank in the future.

Just as background info, I fitted a 130A large-case alternator several years ago to charge a 660Ah battery bank. Never saw more than about 100A charge, and the alternator bracket suffered badly from vibration. Ditched it and put a 90A Prestolite small-case unit on instead - works fine with no practical reduction in charge efficiency. Reckon 90A is about the most you can drive with a single V-belt (you need to get a quality belt; Gates are good).

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[john_morris_uk]

Re: Probably overkill...

The output of alternators degrades with temperature, and suprise suprise, most manufacturers quote the optimum rate before the thing warms up.

If you want to be a bit more scientific, you need to check the output when the things is warm. You might find that the Balmar is not overegging it at all.

Of course, the batteries will only accept the high charge rate initially, the smart regulator will sort out the rate according to what the chemistry of the battery and its state of discharge.

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[Redmond]

I fitted a 90 amp lucas to my 3HM yamaha which I got from Adverc. appart from shimming it up with a washer and having to get a toothed belt ( the smooth one always slipped under load) and making up a new tensioner as the old one wouldnt fit as the body was to fat, it pushes out 100 amp into my 300 amp bank. Marine power will make up double pulleys if necessairy (they sponsor the Yanmar site

Red

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