Alternator for a 1992 Perkins Diesel

[Herb Parsons]

I have a 1971 Coronado 35 that was repowered (before I bought it) with a 1992 Perkins 30 HP diesel. I had a guy working on the boat this a couple of weeks ago, and he tested the alternator output and said it would need to be replaced. I'm having trouble locating an alternator for it. Does anyone have any suggestions on what other model engines to look for and/or places to find a marine quality alternator for it?Also, is the extra advantage of a dual output alternator worth the extra expense (assuming one is even available for the Perkins).My questions may make it obvious, but I'm new to diesel engines, my O'Day 25 has a gas outboard, so any help and/or suggestions are more than welcome.

 

[J.B. Dyer]

Battery Shack

Morning Herb:Try the Battery Shack, web attached.The advantages of a dual output would depend on how many batteries you have and your usage. Your call.You might also think about pulling your existing alternator and taking it to a local alternator/starter rebuilders, there isn't that much difference between auto and marine alternators. If they can rebuild it, it should drop right back in with the same wiring and no alterations. I had a 21 year old alternator rebuilt last year and it works fine.In the event the web attachment doesn't work, just search key words "The Battery Bank". They have a pretty good selection.

 

[Herb Parsons]

Batteries

I have this thing about over-building, I'd rather do extra than not enough. I have 2 batteries on my O'Day 25, all for "house" current (I don't electric start anything). I was thinking at least three on the Coronado, 1 dedicated to starting (just bought a new one) and 2 for house current (haven't bought new yet, and currently only have one older one).My current plans are to keep the boat in the slip at the marina until it's finished being fixed back up (a lot of mostly cosmetic stuff to be done), with a short break on land to haul it and repaint bottom, hull, topsides, and deck. After that, for the next several years, it will be used for primarily coastal cruising, usually long weekends with an occasional 2 week stint. I don't anticipate being away from shore power more than 4 days during this time.After 10 years or so, it's Katie bar the door. No telling what we'll do, or how long we'll be away, though I'm sure we'll not be gone more than 2-3 months at a time.Would a single-output be fine for now, and then purchase a dual at a later date? I also didn't mention, I plan on buying an onboard charger to keep the batteries charged while plugged to shore power (that was the first "upgrade" I did to my O'Day 25).

 

[J.B. Dyer]

Hmmmmm!

You might try checking the archives, there is a formula somewhere where you measure your usage and it calculates out how much battery/charging capability you need.It sound like we pretty much have the same sailing schedule, so let me tell you what I have and it might give you some idea. I have an O34 that stays on shorepower. There is 315amps of house (3) batteries and one dedicated starting battery, with a Xantrex 40 amp. smart charger on board that keeps them tuned up while on shore power. The alternator is the original 50 amp, the one that I had rebuilt. The only thing that I have that runs 24/7 is the refrigerator. The remaining are the lights, radios, nav. instruments and gps that are intermittantly used. I have a 55watt regulated solar panel that supplements the batteries. With the routine use of the engine, in and out of moorings, I have never run out of power, not saying that it can't happen. So far, with the solar panel, I've never had any incentive to go with a bigger alternator, but there is certainly no harm in having more than you need. If it makes you feel better, I'd go ahead and do it.Hope this helps!