I'm looking to replace the aging alternator on my 13HP diesel, a two cylinder Renault 2.6 that's about 20 years old. The current alternator is a Paris-Rhone 12v with 35A output. The attachment point on the motor is 1" wide. Any suggestions as to an appropriate make/model/amperage replacement? Is it ok to use a 50A or 65A alternator as a replacement? Where to buy it? Any help appreciated!
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new alternator
Why do you want to replace it? Is it internally regulated? Do you want more power from it? Were I you, I'd take it to an alt. shop and see if they can rebuild it and modify the internal reg. if it has one. Your problem is going to be the mount. You may have to have a bracket made if you can't do it yourself. Since this one already mounts, try to boost its output and improve its regulation scheme. I think that would be easier/cheaper in the long run.
Why do you want to replace it? Is it internally regulated? Do you want more power from it? Were I you, I'd take it to an alt. shop and see if they can rebuild it and modify the internal reg. if it has one. Your problem is going to be the mount. You may have to have a bracket made if you can't do it yourself. Since this one already mounts, try to boost its output and improve its regulation scheme. I think that would be easier/cheaper in the long run.
More amps and less HP.
Why do you think you want to replace it. The more amps your alternator generates the less horsepower you are going to have at your prop. If it works, I would not mess with it.
Why do you think you want to replace it. The more amps your alternator generates the less horsepower you are going to have at your prop. If it works, I would not mess with it.
With 740 watts per horsepower
it translates to about 60 amps per hp. So up grading from a stock 50 amp alternator to 100 amps( can't imagine why) would only cost you 1 hp. My 13x15 prop on my Islander 30 absorbs about 6 hp and my engine is 10 hp so there is plenty of reserve.
it translates to about 60 amps per hp. So up grading from a stock 50 amp alternator to 100 amps( can't imagine why) would only cost you 1 hp. My 13x15 prop on my Islander 30 absorbs about 6 hp and my engine is 10 hp so there is plenty of reserve.
Don't forget the extra pully
While your engine may have the power to turn the bigger alternator, V shaped drive belts are only rated at about 1.0 HP. That is why you see duel belts on anything over about 60 amps and why most engines come with less than 60 amp alternators. So what do you do when you go to a 120+ amp alternator? Glad you asked, the flat belt with the grooves on the inside (serpentine) is rated to 5 HP and would be good to power up to 300 amps.
While your engine may have the power to turn the bigger alternator, V shaped drive belts are only rated at about 1.0 HP. That is why you see duel belts on anything over about 60 amps and why most engines come with less than 60 amp alternators. So what do you do when you go to a 120+ amp alternator? Glad you asked, the flat belt with the grooves on the inside (serpentine) is rated to 5 HP and would be good to power up to 300 amps.
RFerraro
Check the west marine catalog. They have pictures of all the alternator bolt configurations and the "industry name" for each. They may have it on there web site too. Then you can look around the internet for your "type" with a little more confidence. With all that said; alternators are pretty durable items. Just because it is old is no reason to replace it if it still works. Bearings and brushes are about the only thing that wears out and these are easy (and cheap) to replace. Now if you want to up the power output to run something then a little "power usage" analysis it in order. This always leads to the alternator output - battery storage - electrical usage conversation that is common on this site. I made an excel spreadsheet that lets you "play" with the numbers on all this stuff if you need to do the analysis. Drop me an email if you want a copy. roosaw@saic.com
Check the west marine catalog. They have pictures of all the alternator bolt configurations and the "industry name" for each. They may have it on there web site too. Then you can look around the internet for your "type" with a little more confidence. With all that said; alternators are pretty durable items. Just because it is old is no reason to replace it if it still works. Bearings and brushes are about the only thing that wears out and these are easy (and cheap) to replace. Now if you want to up the power output to run something then a little "power usage" analysis it in order. This always leads to the alternator output - battery storage - electrical usage conversation that is common on this site. I made an excel spreadsheet that lets you "play" with the numbers on all this stuff if you need to do the analysis. Drop me an email if you want a copy. roosaw@saic.com
Thanks to all
For your responses. I neglected to say that the reason for changing the alternator is that is freezing up on occasion and requires gentle persuasion with a hammer to get it spinning freely again. No need for additional amperage. I think West Marine might be the way I go. Thanks again.
For your responses. I neglected to say that the reason for changing the alternator is that is freezing up on occasion and requires gentle persuasion with a hammer to get it spinning freely again. No need for additional amperage. I think West Marine might be the way I go. Thanks again.
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