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Old 02-23-2018, 02:43 PM   #21
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Originally Posted by Westiculo View Post
I don't understand the "3-5 times more current" - are you saying that his 65-amp alternators are actually only putting out 20 amps
Yes, that is exactly what I am saying. Here are some real world figures:

With an OEM standard Hitachi internally regulated 55A alternator feeding a 25% depleted 440 AH GC battery bank I measured 15A from the Hitachi after ten minutes of engine running time.

With a 110A Balmar HO alternator feeding the same bank 25% depleted I measured 60 amps from the Balmar alternator.

Most internally regulated alternators are not designed to put out a lot of current no matter what their amp rating. They are regulated at a fixed 13.5 V output and that isn't enough voltage to push much current into the battery. Under the same conditions the Balmar alternator/regulator was reading about 14.0 volts.

So if you take that puny OEM alternator and amp it up with an external regulator so it puts out the same 60 amps as the Balmar, it is going to get really hot after a while. Heat kills alternators.

High output alternators like the Balmar have heavier windings than the Hithachi (less voltage drop therefore less heat), heavier diodes (same) and more cooling air due to a more efficient fan.

But if you were to try to recharge a huge 1,000 AH bank fully depleted the Balmar will get too hot. That is why Balmar makes a temperature sensor that dials back the alternator output when it reaches about 200 deg F case temperature.

David
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Old 02-23-2018, 06:05 PM   #22
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I replaced my old Delco OEM for my Perkins main engine with an ARCO model 60122 105 amp . The output wire needed upgrading to #6 and the tachometer wires needed modification. I also needed to improvise spacer washers to get the pulley alignment right on. With a single belt, I measure 104.5 amps at 1400 engine RPM until battery volts reaches 14.4 volts, then maintains 14.4 volts until I come down to idle and start using either the windlass or thruster. I charge 6 - 6 volt wet cell Trojan golf cart batteries. No signs of any overheating damage in about 400 hours of cruising. Pretty easy upgrade if you don't want to go full Balmar $$$$.
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Old 02-23-2018, 07:02 PM   #23
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What amperage alternator

If the batteries are in bulk charge (I think I have my terms correct), you can totally connect the two alternators together without using an outboard regulator. They will take what you throw at them, but for sure, a stock 65A alternator ain’t puttin’ out no 65A. Still, he needs to work all this out before he goes and buys a $1000 alternator or a fancy voltage regulator.

That’s all I’m sayin’.

My two stock 65s give me about 60A combined when underway. Not enough for my 8 golf cart batt/900AH bank, but plenty for now. We are still just weekenders.
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Old 02-24-2018, 06:24 AM   #24
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"My question was mean to be related to the "3-5 times more current" comparing an internal to externally regulated alternator. Any thoughts on that?"

The brain in a std alt is expected to replace perhaps 5% of the battery capacity , and hold the voltage up to 14+ so the lights and blower motors .

They are seldom asked to charge a well discharged batt as start batts DIE if any attempt to deep cycle them is made.

Repeated cranking covers the plates with gas , so the batt stops working for the time it takes the gas to depart, it has not been very deeply discharged .

The V reg of a car alt allows only about 50% of the required charge in any hour (to keep the load & internal heat low.

While a one wire alt can be modified to use an external V regulator , it is far simpler to install a rebuilt 75 or 80A from an early large car, and then install the 3-4 stage regulator.

The old Delco stuff from 70's Caddys was quite robust, and still cheap.
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Old 02-24-2018, 07:13 AM   #25
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As previously mentioned, I have a Leece Neville 220 amp alternator, Sterling 3 stage regulator, and a Victron Energy battery monitor. The alternator is designed for fire trucks and other vehicles that require high continuous amps when operating at low RPMs. As an example of how my system works, consider the following :

We left Fort Myers for Fort Pierce. On the second night we were on the hook and ran the ice maker all night to fill a large beer cooler. In the morning, the bank (1,000 amp lead acid) was down to 70%. After pulling the hook and getting underway (engine RPM 1,500), the battery monitor was showing 180 to 200 amps going into the battery bank. After the bulk stage ended, you could watch the amperage slowly drop during absorbtion stage. By the time we reached Fort Pierce (4 hours of motoring), the bank was basically full (10+/- amp charge or 1% of bank capacity).

This type of bank recharge is typical for my system and demonstrates what can be accomplished with a commercial grade continuous duty rated alternator and 3 stage regulator.

The reduction of amps from the 220 amps which the alternator is rated for, comes from power consumed by the boat and the inverter.

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Old 02-24-2018, 08:14 AM   #26
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Quote:
Originally Posted by FF View Post
"My question was mean to be related to the "3-5 times more current" comparing an internal to externally regulated alternator. Any thoughts on that?"

The brain in a std alt is expected to replace perhaps 5% of the battery capacity , and hold the voltage up to 14+ so the lights and blower motors .

They are seldom asked to charge a well discharged batt as start batts DIE if any attempt to deep cycle them is made.

Repeated cranking covers the plates with gas , so the batt stops working for the time it takes the gas to depart, it has not been very deeply discharged .

The V reg of a car alt allows only about 50% of the required charge in any hour (to keep the load & internal heat low.

While a one wire alt can be modified to use an external V regulator , it is far simpler to install a rebuilt 75 or 80A from an early large car, and then install the 3-4 stage regulator.

The old Delco stuff from 70's Caddys was quite robust, and still cheap.
Don't try this is you have gassers. We become so accustomed to talking trawlers with diesels. Some safe diesel practices can be hazardous it tried with gassers.
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Old 02-24-2018, 08:34 AM   #27
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O C Diver's experience with the Leece Nevile alternator and the Sterling regulator is impressive.

As I recall, the Sterling regulator is unique in that it "fools" the alternator into thinking it is supplying a low impedence load at a reduced voltage thereby boosting its amperage and then boosting the voltage to what the battery needs. Sort of like a reverse MPPT controller.

That means the Sterling regulator can be used with a one wire alternator as no field connection is needed. But only use it on an alternator that can stand up to the long term load like the Leece Neville.

David
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Old 02-24-2018, 09:21 AM   #28
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Leece Neville is owned by Prestolite. Many other alternators out there that are installed in big equipment that match the LN's well deserved reputation. They may well be made by Prestolite too.
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Old 02-24-2018, 12:19 PM   #29
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There are a few makers of quality HO alts, not many, and several are very specialized low volume like Eco-tech and Zena.

​Ex-military C.E. NIEHOFF & CO (CEN) units can be found reasonably on eBay, some put out 500+A at 24V.

Of course the higher the load the more of your engine's propulsion HP is diverted. I figure that latter example would take about 30HP per alt.

Need a solid belt/pulley setup!
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Old 02-24-2018, 02:26 PM   #30
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Quote:
Originally Posted by djmarchand View Post
O C Diver's experience with the Leece Nevile alternator and the Sterling regulator is impressive.

As I recall, the Sterling regulator is unique in that it "fools" the alternator into thinking it is supplying a low impedence load at a reduced voltage thereby boosting its amperage and then boosting the voltage to what the battery needs. Sort of like a reverse MPPT controller.

That means the Sterling regulator can be used with a one wire alternator as no field connection is needed. But only use it on an alternator that can stand up to the long term load like the Leece Neville.

David
My understanding of how the electronics work in the regulator is poor. But, you do have to be able to connect to the positive brush in the wiring process. You can leave the original regulator in place and it functions as normal if the Sterling regulator is turned off.

Quote:
Originally Posted by john61ct View Post
There are a few makers of quality HO alts, not many, and several are very specialized low volume like Eco-tech and Zena.

​Ex-military C.E. NIEHOFF & CO (CEN) units can be found reasonably on eBay, some put out 500+A at 24V.

Of course the higher the load the more of your engine's propulsion HP is diverted. I figure that latter example would take about 30HP per alt.

Need a solid belt/pulley setup!
I added a second 8 groove serpentine belt pulley to the crank shaft which only drives the second alternator. At full load, the engine fuel consumption goes up approximately .3 to .4 gallons per hour. Assuming 20 HP per gallon, this 220 amp alternator requires a maximum of 8 HP.

Ted
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