H33 Alternator upgrade

[SMACGW]

On a 1983 H33 with a 2GM 15HP diesel, stock 35 Amp Hitachi aletrnator, can I have the Alternator rebuilt to a 80 Amp ( a 100 Amp is too big??), if I can rebuild it, what do I need to add?
The Balmar Alternators are too overpriced.

COL SM W

 

[wufibugs]

I'd check ebay by searching alternator, hitachi, yanmar. I see 60 and 100 amp models for $85-125.

 

[Ed Schenck]

Talk to your local automotive electric shop. I have had Hitachis rebuilt by them but never rewound. I doubt think it can be done.

I bought a 50 amp Hitachi for my 2QM20 way back when and it served me nicely. You have to do some rewiring when you move up. The higher amp alternators use an exciter voltage, kind of like a kick start. This is true of the 50 amp Hitachi and the Balmar. I agree with Richard that a used Hitachi is your best bet. I did install a Balmar on my new 3YM30 but I sold the 80 amp Hitachi.

 

[Honeyman]

I'd stay 80 amp or less...going to steal quit a bit of your horsepower to drive that or anything larger.

 

[wufibugs]

The one I would tend to go with is the 60 amp for $125 as that is all the hp I would be willing to sacrifice. The ebay seller says the unit is new, not rebuilt. I am not sure they can claim new if it is remanufactured. Now that I think about it, not sure I know what the difference between "rebuilt" and "remanufactured is.

 

[Benny]

At 15hp for a 33 ft Cherubini you are currently already underpowered. It takes HP to drive the alternator and the larger the alternator the less power is available to drive the boat. A larger alternator does not necessarily result in significant recharching time savings. The type of batteries and their charge acceptance rate may dicate the time. The size of the battery bank is also a determining factor. Boats that have larger banks that the standart 2 Group 27 lead/acid setup coupled with high usage may benefit. Larger alternators may require mounting bracket reinforcement and over 100 Amps double belts to avoid slipage are recommended. Perform a power survey on your boat and do your homework before making any modifications as there are pros and cons. We run a 2GM 18HP on our 32' and have the factory mounted 55 Amp Hitach. We run refrigeration and find the setup more than adequate for coastal cruising.

 

[Ed Schenck]

The 60 amp would be a nice upgrade not requiring the expense of a regulator. In this picture( http://www.spidermarine.com/UserData/Images/Large/100438.jpg ), near the top, there is a recess with two spade terminals. One is marked 'L', the other one is 'R'. I ran a wire from the start post on the starter solenoid to the 'L' terminal to get my exciter voltage. In other words there is 12 volts to the alternator just while you are starting the engine. This is sufficient to "charge" the stator field.

I think that I am remembering that right. I cannot find the thread where we discussed this back in 2000 or 2001.

P.S. found a better picture in my files.

 

[wufibugs]

Interesting that Benny's 2GM came with a 55 amp alternator and my 2GM*F, supposedly putting out 20hp, came with a 35.

 

[Scott B]

I did install a Balmar on my new 3YM30 but I sold the 80 amp Hitachi.

Ed, what did you install on your 3YM30. Something I need to look at is ways to make more battery juice and I thought I'd upgrade the stock alt. that came with our 3YM30.

 

[Ed Schenck]

Strange as it seems I went with the same size, an 80-amp Balmar. Long story but I already had a new 3-stage alternator. I looked at modifying the Hitachi for external regulation. Decided against it, sold the Hitachi and bought the Balmar. Its a little light for my 400 amp-hour house bank. Still I find my five AGMs at 12.75 most of the time.

 

[Scott B]

Strange as it seems I went with the same size, an 80-amp Balmar. Long story but I already had a new 3-stage alternator. I looked at modifying the Hitachi for external regulation. Decided against it, sold the Hitachi and bought the Balmar. Its a little light for my 400 amp-hour house bank. Still I find my five AGMs at 12.75 most of the time.

Torresen has an aftermarket 94 amp from API for the 3YM30, is it really going to make a big difference from the stock 60amp. During our trip I watched the batt monitor closely (didn't have one last year ) and noticed I could only get 20 - 30 amps at most charging and then trailed off to 12-13 amps with acceptance rate.

 

[Bill Roosa]

Bingo Scott

Batteries control how much current the alternator puts out. Now if you had a 20 amp alternator and upgraded to a 30 that would help but from what you are seeing on your battery monitor going much over 30 is not going to help at all (except to drain your wallet)
The bank size and alternator max output and how deeply they are discharged all play in charging current rates. How deeply discharged depends on how you us your batts.
My 150 amp alt (PO installed) will go to 75 amps once in a great while but only for a few minutes then it is back to the 30-40 amp range. 20-30 is much more typical on my 400 AH bank.

 

[Benny]

Wufi, I think the reason may be that in later years with the addition of electronic items the manufacturers have upgraded the recharging capabilities. Our boat came equipped with 12V refrigeration, halogen lights, a macerator, propane solenoid, cockpit courtesy lights and others. Our 2GM20F is rated at 18 HP and with our boat displacing 12K+ lbs. we find it is significantly underpowered. Our 55 amp alternator is very adequate for our use and would not consider upgrading it. For extended trips we pack a Honda 2000eu generator which allows us to recharge batteries at anchor but for day sailing we rely on a modest battery bank and the alternator.

 

[Scott B]

Batteries control how much current the alternator puts out. Now if you had a 20 amp alternator and upgraded to a 30 that would help but from what you are seeing on your battery monitor going much over 30 is not going to help at all (except to drain your wallet)
The bank size and alternator max output and how deeply they are discharged all play in charging current rates. How deeply discharged depends on how you us your batts.
My 150 amp alt (PO installed) will go to 75 amps once in a great while but only for a few minutes then it is back to the 30-40 amp range. 20-30 is much more typical on my 400 AH bank.

Right now I have 2 - 27's. Intent was last spring to go 4 golf cart batt's, but didn't get to it. I'm thinking I'll need more output from the alt to keep up, but not sure if the jump from 60 - 94 would be significant enough.