Universal M30 Alternator Upgrade

[NCTim]

Hi, I am new to SailNet and this is my first post, so I hope I am doing it right! I recently bought a Cabo Rico 34 which has the above diesel and a standard alternator. I am planning extensive cruising and am in the process of upgrading batteries, battery charger, adding solar, etc. As part of this upgrade I want to replace the alternator with a high output 90-100 amp one. I am getting mixed messages from local mechanics about doing this. Has anyone on the forum done this and would those with expertise/experience in this area please give me your input and advice. Thanks.

[JimsCAL]

This excellent article may be of interest.

Universal Diesel M-25 Alternator Upgrade Photo Gallery by Compass Marine at pbase.com

[NCTim]

Thanks, that is an excellent article. It encourages me that what I want to do is possible. Will discuss with my favorite mechanic who has been discouraging me from pursuing this course.

[Maine Sail]

Originally Posted by NCTim

Thanks, that is an excellent article. It encourages me that what I want to do is possible. Will discuss with my favorite mechanic who has been discouraging me from pursuing this course.

On what basis has he been discouraging you?

[NCTim]

My 30 HP engine and its small pulley will not accomodate the larger belt and strain of a high output alternator.

[Maine Sail]

Originally Posted by NCTim

My 30 HP engine and its small pulley will not accomodate the larger belt and strain of a high output alternator.

The 3/8 belt can do about 75 to 80 amps but you'll still get some dusting. If you want to go larger than 100 amps, or don't want to deal with belt dust, call John at Electromaax and he can make you a custom serpentine pulley kit. Their alts are also top quality and very, very robust.

[NCTim]

Thanks, I really appreciate the tip. I will give John a call.

[wescarroll]

I just put a 100 amp 1/2" drive single wire GM style alternator in my 18m. Simple bolt in replacement and with a quality Gates replacement belt have had no problems. Just google universal replacement marine alternators and keep going until you find one you like. Mine cost $60 plus $10 shipping from an outfit through amazon. Single wire units don't have a post for a tach, but a local rebuilider can add one. I just installed a larger belt in place of the 3/8" and it seemed to fit as if that was the correct size right from the beginning.