External regulator

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east coaster

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Apr 10, 2010
43
Catalina 310 166 Dartmouth, Nova Scotia
I have a Catalina 30 #2444, with a 2GM Yanmar raw water cooled. The 55 amp Hitachi alternator with internal regulator was giving me 14.4 volts but little or no amps. Qualified and trusted diesel electric firm tested and advised either rebuild or new. Went for new about $300 CDN. Want to install external Sterling regulator and have received incredible amount of advice on how to do it. Advice varies from don't to very detailed and complicated alternator tear down, soldering wires to brushes, rip out internal regulator and so it goes on. Best I have seen is in the Diesel Afloat book by Pat Manley. Solder one wire to the field wire, lead it outside and connect to your external reg. He is even talking about a Hitachi just like the one I have. So the question is, has anyone out there in the wide sailing community ever done this using a similar set up and Manleys advice, or what advice do you offer? I am wide open here so would appreciate any assistance at all. Thanks :confused:
 
Don S/V ILLusion

Don S/V ILLusion

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Sep 25, 2008
7,099
Alden 50 Sarasota, Florida
I'll leave the rebuild/replace advice to others but before going further, it would be useful to know how large a battery bank you are charging as everything is dependent upon that.
 
Maine Sail

Maine Sail

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Feb 6, 1998
11,674
Canadian Sailcraft 36T Casco Bay, ME
If you are already at 14.4V what is it you expect to get from the Sterling?

Bulk is bulk, whether internal or external, and your absorption voltage is not half bad at 14.4V. Sure you can put a little more "pressure/voltage" in and go for 14.8V but it won't change much as the charging above 80% SOC is controlled by the bank acceptance. A few more tenths of a volt will increase "acceptance" slightly but not by a huge margin. The biggest issue with the Hitachi alts is some have temp protection built in so when they heat up they can cut the field back. The Sterling or Balmar regs would do the same if you use the temp sensor.

We need more info about your failure..... Was it putting out zero amps or just low amperage?

Hitachi alts can be converted to external but they are more of a PITA than most..

Bank size?
Battery type?
Alternator wiring?
Average dept of discharge?
Daily Ah use?
 
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Benny17441

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May 24, 2004
7,131
CC 30 South Florida
Any upgrade or modification should be justified by a specific need. I like that you replaced your faulty alternator with a new Hitachi; the after market units just do not offer the reliability of the original equipment. At $CAN 300 that is not a cheap replacement so have you considered how your rewiring the unit may affect the warranty? Like Don suggested the key here is likely the type and size of your battery bank. An external regulator is not going to change the fact that alternator has an outpout rating of 55 amps and probably the gains to be acquired in recharging times are likely small to justify the necessary modifications. I would advise against it unless you have a very specific need for that modification.
 
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JohnShannon

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Jan 4, 2010
1,037
Farr 30 San Francisco
It doesn't sound like anything is broken. 14.4V is plenty to keep the batteries charged. If your alternator wasn't working you would find a battery voltage of 12 and still no/low charging current.

Why do you think anything is broken? Hard cranking? perhaps you just need to clean your battery connections. Maybe your batteries are toast?

Once the alternator is putting out 14.4V it really can't do much more than that.
 
Don S/V ILLusion

Don S/V ILLusion

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Sep 25, 2008
7,099
Alden 50 Sarasota, Florida
I always wonder why some people ask a question and then never bother to come back to respond. Wastes everyone's time.
 
Maine Sail

Maine Sail

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Feb 6, 1998
11,674
Canadian Sailcraft 36T Casco Bay, ME
Don S/V ILLusion said:
I always wonder why some people ask a question and then never bother to come back to respond. Wastes everyone's time.
Click to expand
He'll probably be back but just wants to give it some time. Many forums don't move as fast as this one..
 
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alexco38

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Sep 25, 2008
1,096
CS 30 Toronto
My Paris Rholm 60A alternator (Volvo engine) gave up due to regulator failure. Went to a auto electric repair shop and have the regulator replaced for $30. Your 14.4V output means it is working. Why do you want to change it?

The guy shown me a used AC Delco 90A GM truck alternator for $90. Aside from the color it looks exactly like the $300 Balmar. They guy tap out a AC output for the RPM gauge for free.

Now I have a 90A alternator with a spare 60A. The 90A enable me to run an AC invertor for the microwave with the engine running. I never run invertor on DC alone.
 
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Benny17441

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May 24, 2004
7,131
CC 30 South Florida
Alexco you have hit into something the automotive manufacturers have used for years and that is to power high draw items from pass through power delivered by high amp alternators. The problem we have is that our small auxiliary engines loose a significant percentage of horsepower and are subject to added wear and tear from running a high output alternator. We usually just consider alternators in their capacity to recharge batteries but having adequate pass through power may be a consideration for some.
 
Maine Sail

Maine Sail

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Feb 6, 1998
11,674
Canadian Sailcraft 36T Casco Bay, ME
Benny17441 said:
Alexco you have hit into something the automotive manufacturers have used for years and that is to power high draw items from pass through power delivered by high amp alternators. The problem we have is that our small auxiliary engines loose a significant percentage of horsepower and are subject to added wear and tear from running a high output alternator. We usually just consider alternators in their capacity to recharge batteries but having adequate pass through power may be a consideration for some.
Click to expand
Westerbeke / Universal suggest that their engines can handle up to 190A of alternator without "damage" to bearings and such. With small engines this will cut into HP a bit and you'd need a dual pulley or a serpentine kit. With LiIon battery technology coming down the pike, and 5-C acceptance, many boaters will be looking at 150A + units pretty soon.

The big difference between a HO marine alt and a car alt is low RPM output. The HO alt will be wound so that it can achieve 80-90% of its hot rating at engine idle speed or roughly 2000 alternator RPM.. You can convert just about any alternator to have an AC tap or external regulation, and even ignition protection, but short of re-winding it you're not going to change its low RPM performance.
 
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Benny17441

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May 24, 2004
7,131
CC 30 South Florida
Good info Maine, I'm sure some people can benefit from it. I would probably need to repower if I wanted to run a 150A alternator, my 18HP Yanmar could not take that hit.
 
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