High Output Alternators

[downunder]

Thanks Mainsail,

What I wanted to know.

Your how to website info is greatly appreciated.

[mcarling]

Originally Posted by Vasco

I have a KISS wind generator and a Honda EU2000i. When I bought this boat (2004) solar panels were too expensive. They have come down now but I have yet to spend any time in a spot where I could get solar installed. I get down to the boat in FL, paint the bottom, throw it in the water and off I go. It is difficult to get any major work done when cruising and at the end of the season all I want to do is haul the boat and go home. I keep talking about getting solar panels though, maybe this season.

Can you install the solar panels (or have them installed) while your boat is at home on the hard?

[Amnesia II]

Mainsail, In your photo I notice you have a large negative cable on the alternator casing. Where do you take this cable back to....the neg battery post directly?

[DevoDave]

Originally Posted by Amnesia II

Mainsail, In your photo I notice you have a large negative cable on the alternator casing. Where do you take this cable back to....the neg battery post directly?

The answer should be yes.

[Vasco]

Originally Posted by mcarling

Can you install the solar panels (or have them installed) while your boat is at home on the hard?

No, I'm 1500 miles away and the boat is all covered up. I'd like to see it being done. Might stay someplace in FL for 2 weeks this year and see if I can get someone to do it.

[Bambolera]

I setup my own system with a high amp alternator. If I let the bank discharge too much, I have trouble starting the engine due to the load created by the alternator. I want to install a switch to the (field wire?) until the engine is up to speed before flipping the switch to start charging, but I've heard that the diodes can be damaged.

Somewhere in this thread, I read that a delay can be rigged. Can someone please tell me how this is done and/or discuss other options for engaging the alternator manually.

John

[witzgall]

If you happen to have a Balmar external regulator, it most likely can be setup to do this. Ours has a provision to setup a switch that will drop to output to a percentage charge, and you can set the percentage.

If you don't have an external regulator, then you should consider getting one, if you are using AGM, gels or LIFEPO4, as the alternators will tend to get quite hot running at high amps for extended periods of time, and will short-life the regulator.

Chris

Originally Posted by Bambolera

I setup my own system with a high amp alternator. If I let the bank discharge too much, I have trouble starting the engine due to the load created by the alternator. I want to install a switch to the (field wire?) until the engine is up to speed before flipping the switch to start charging, but I've heard that the diodes can be damaged.

Somewhere in this thread, I read that a delay can be rigged. Can someone please tell me how this is done and/or discuss other options for engaging the alternator manually.

John

[Blue Stocking]

Originally Posted by Bambolera

I setup my own system with a high amp alternator. If I let the bank discharge too much, I have trouble starting the engine due to the load created by the alternator. I want to install a switch to the (field wire?) until the engine is up to speed before flipping the switch to start charging, but I've heard that the diodes can be damaged.

Somewhere in this thread, I read that a delay can be rigged. Can someone please tell me how this is done and/or discuss other options for engaging the alternator manually.

John

AC Delco, (try truck part suppliers) make a heavy duty, oil pressure operated switch, normally Tee'd off the oil sender unit. Pass your field current through switch to delay alt load on engine.
Teleflex also make a NO/NC switch.
Quite common for dual alternators.
Most modern regs have a ramp-up delay built in.

[Bambolera]

I have a large frame Leece Neville truck alternator, rated at 130 amps. It's not marine equipment, but I've been using it for 11 years (full time cruising) and have never had a problem. The alternator has an external regulator (attached to the back) and can be adjusted for voltage by turning the set screw on the back.

There are three terminals on the back, which appear to be for adding equipment. Would this work for the oil temperature sensor? Wouldn't it be easier to wire in a manual switch and turn it on after the engine is running?

The attached link shows the alternator, now rated at 160 amps.

110-902-LEECE NEVILLE-ALTERNATOR

[Bambolera]

This link has several good photos of the 130 amp model.

Leece Neville 8SA2035VA 12V 130Amp Alternator New | eBay

[DeepFrz]

With a high output alternator it is important to have a regulator that will ramp up the load. Otherwise you are going to be breaking alternator belts often.

[Amnesia II]

Originally Posted by Amnesia II

Mainsail, In your photo I notice you have a large negative cable on the alternator casing. Where do you take this cable back to....the neg battery post directly?

The thing is, there is already a neg cable returning from the battery bank to the engine block. The alternator is securely bolted to the engine block so therefore is directly connected to the neg side of battery bank.

So what is the point of another neg battery cable returning as Mainsails photo shows?

[Maine Sail]

Originally Posted by Amnesia II

The thing is, there is already a neg cable returning from the battery bank to the engine block. The alternator is securely bolted to the engine block so therefore is directly connected to the neg side of battery bank.

So what is the point of another neg battery cable returning as Mainsails photo shows?

The point is that the "case ground" run though the engine block is a HORRIBLE way to get a hundred + amps back to the battery bank without suffering some serious voltage drop issues either now or in the near future.

Running an alternator through numerous different metals, that offer lower conductivity than copper, through pounds of rust, grease, corrosion and paint causes problems with HO alts. It actually causes just as many problems with factory alternators that don't have a way to "sense" and try to compensate for voltage drop....

It also causes issues with starter motors and I often run a neg wire directly to the ear of the starter not the opposite side of the engine block 18 different connection points away. The differences in the way the motor starts are often quite noticeable and dramatic...

I am the guy often called in to fix alts that suffer from voltage drop and the resultant chronic under charging that accompanies this voltage drop. More often than not the majority of the voltage drop is in the NEG side of the circuit but it is often a decent split especially with factory wiring...

I fix this by using the alts "isolated ground" terminal or I clean a good spot on the alt case when it is case grounded. I also use conductive terminal grease to maintain this connection. I lead a new wire, the same size as the POS, directly back to the bank or the load side of a shunt if so equipped.. There is a good reason HO alternators usually require a NEG cable the same size as the POS cable. Creating the most direct path back to the battery bank, on both sides of the circuit, results in the best alternator performance.

I often deal with & fix voltage drop issues by adding a new NEG cable the same size as the POS direct from the alt to the bank.. It is not uncommon to see a 1Ga POS wire and a 10GA NEG run through the factory wiring harness, to a rusty engine block, grease, corrosion, paint and multiple engine components before it gets to the cable that takes it back to the battery bank.

After this new cable has been installed I regularly see 90%+ of the current flowing though the new cable vs. the engine block path... The before and after is easily measured with a clamp meter. The path of least resistance is the best path when dealing with something as important as charging voltages and not allowing them to be eaten up though poor conductive paths..

[Nicholson58]

If you need a large alternator go to a rebuild shop for alternotors and starters for class 8 and other big trucks. we had our 2KW alternotor rebuilt for 60 bucks. rebuilts for affordable prices.

[Amnesia II]

Mainsail, thankyou for your excellent response re the neg battery cable...I'm very much enlightened!