Installing new alternator

[kenbo]

Originally Posted by Wotname

Hmm... I would strongly advise the wire going from or to the resistor (or lamp) be switched by the key (ignition) switch.

This wire (which goes to the L termination) provides the initial excitation voltage for the field. If left unswitched, the field current will flow even when the alternator is stationary.

I can post the internal wiring of the alternator if you need it.

I was suggesting that as a test mode only to see if the alternator was operational. See post #6. I hope the OP got that this was a temporary hook up???

[Wotname]

Originally Posted by kenbo

I was suggesting that as a test mode only to see if the alternator was operational. See post #6. I hope the OP got that this was a temporary hook up???

Yes, I agree

[chris mac]

Originally Posted by kenbo

I was suggesting that as a test mode only to see if the alternator was operational. See post #6. I hope the OP got that this was a temporary hook up???

Understood

[kenbo]

Bueno amigo

[chris mac]

So no luck getting a resistor I have some ordered should be a couple days.
In the meantime I did find a battery for my wire chaser. I have 2 wires coming off the light. Both have no voltage with key off.
With key on they are White red reading 3.2v , blue black reading 11.8v.
Which confuses me more.
I also have an old plug long left vacant that will fit the alternator. Red goes through a fuse and attaches to pos terminal, but the blue wire dead ends behind the control panel. No idea where it went.
As I mentioned, saving to put new panels and harness next year. But this rat's nest gets confusing!

[kenbo]

Originally Posted by chris mac

So no luck getting a resistor I have some ordered should be a couple days.
In the meantime I did find a battery for my wire chaser. I have 2 wires coming off the light. Both have no voltage with key off.
With key on they are White red reading 3.2v , blue black reading 11.8v.
Which confuses me more.
I also have an old plug long left vacant that will fit the alternator. Red goes through a fuse and attaches to pos terminal, but the blue wire dead ends behind the control panel. No idea where it went.
As I mentioned, saving to put new panels and harness next year. But this rat's nest gets confusing!Attachment 223947Attachment 223948

Actually that plug makes sense to me. The fused red wire going to the Bat+ and the top, horizontal terminal is your voltage reference sense. The dead end blue wire on the lower vertical blade is your power source for the voltage regulator.

As to wires coming off the charging indicator light, the one with 3.2v is the one going through the light. The light has resistance which lowers the voltage. The other wire showing 11.8v is your voltage reference sense which should go to the top, horizontal blade.

As a test, measure the voltage of the battery that's supplying power to the ignition switch and then compare that voltage to the wire that you measured to be 11.8v. Is there a difference? I'll bet there is, that's why the voltage reference sense wire should go directly to the battery.

That lower voltage wire with 3.2v just powers the voltage regulator until the alternator starts producing voltage. After that the diode trio powers the rotor field coil. Your Hitachi alternator has a voltage regulator that controls the strength of the field coil on the negative or low side of the field coil. That's different than most Delco alternators and most external voltage regulators, they control the field strength on the positive or high side. Same result different approach.

[chris mac]

So if I'm understanding properly. Best practice would be 3.2 v wire connect to the blue out of the plug.
Red wire from plug run straight to battery positive.
(Keep fused I assume)
Main (large 12v) keep on positive terminal for charging
Grounded to engine block thru mount
Is that correct?
Edit... yes, voltage drop from switch. Batteries were at 12.5 at that point.

Originally Posted by kenbo

Actually that plug makes sense to me. The fused red wire going to the Bat+ and the top, horizontal terminal is your voltage reference sense. The dead end blue wire on the lower vertical blade is your power source for the voltage regulator.

As to wires coming off the charging indicator light, the one with 3.2v is the one going through the light. The light has resistance which lowers the voltage. The other wire showing 11.8v is your voltage reference sense which should go to the top, horizontal blade.

As a test, measure the voltage of the battery that's supplying power to the ignition switch and then compare that voltage to the wire that you measured to be 11.8v. Is there a difference? I'll bet there is, that's why the voltage reference sense wire should go directly to the battery.

That lower voltage wire with 3.2v just powers the voltage regulator until the alternator starts producing voltage. After that the diode trio powers the rotor field coil. Your Hitachi alternator has a voltage regulator that controls the strength of the field coil on the negative or low side of the field coil. That's different than most Delco alternators and most external voltage regulators, they control the field strength on the positive or high side. Same result different approach.

[kenbo]

Originally Posted by chris mac

So if I'm understanding properly. Best practice would be 3.2 v wire connect to the blue out of the plug.
Red wire from plug run straight to battery positive.
(Keep fused I assume)
Main (large 12v) keep on positive terminal for charging
Grounded to engine block thru mount
Is that correct?
Edit... yes, voltage drop from switch. Batteries were at 12.5 at that point.

That all sounds correct. I really dislike grounding the alternator through the engine block but not knowing the boats wiring it seems like you have to go this way.

[chris mac]

Originally Posted by kenbo

That all sounds correct. I really dislike grounding the alternator through the engine block but not knowing the boats wiring it seems like you have to go this way.

I will see what I can do for an additional ground. Batteries are just through a bulkhead. So pretty easy to add.

[chris mac]

Originally Posted by kenbo

That all sounds correct. I really dislike grounding the alternator through the engine block but not knowing the boats wiring it seems like you have to go this way.

I setup as discussed. No love!
I swapped out to the 2nd alternator, same.
So we brought out a mechanic we trust, he checked and said both were toast.
That's what I get for buying engine parts off amazon!
They are going back, and new ones are ordered through the marina here.
Thanks for the help

[chris mac]

It is now working!
Turns out it was the ground,but an internal ground to an insulated post
The mechanic ordered me replacements from his supplier. They are exact replicas of the ones I have, except they come with a wiring diagram
Once I moved the ground, it worked perfectly.
Thanks for the help everyone!
And heres the diagram to help anyone downstream that finds this thread with a similar problem

[Wotname]

^^ Thanks for the update. Good to hear the outcome was positive

[witzgall]

Chris from Balmar here. We have a sleeper product many don't know about. It is a conversion kit for the 120a VALEO alternator typically found on Yanmar 2012 and newer engines. You can convert these to external regulation in about five minutes on the bench, using a single nut driver. The kits come with an external regulator, and for the 12v versions also provide Balmar SmartReady functionality.

Here is the web page: https://balmar.net/smart-ready-retrofit-for-yanmar/

Chris

Originally Posted by Stu Jackson

FYI on Hitachi alternators:


Hitachi/Yanmar Alternators: (by Maine Sail)

Some alternators though, such as those made by Hitachi and found on Yanmar diesels, are dumber than a pound of beetle poop. Actually, to the alternator, they are pretty smart but to your batteries and the speed of charging they are flat out stupid. Why?

Hitachi alts with dumb regulators, and some others, limit voltage but also reduce voltage based on alternator temperature. This is a self protective feature installed in the internal dumb regulator to prevent the alternator from cooking itself. Remember voltage is the pressure that allows more current to flow. So, if we reduce the absorption voltage, then we also reduce the current the alternator is supplying.. Any battery at any state of charge simply will not accept the same current at 13.4V that it did at 14.4V and as a result the alternator will run cooler. What do you suppose this does to your batteries over time.......?

The problem is that when cold you will get 14.3V to 14.4V out of the Hitachi but as the alternator heats up the dumb regulator begins to reduce the CV/voltage limit based on the alternators internal temperature. It is not uncommon to find a Hitachi alternator at 13.4V when hot. This is REALLY, REALLY DUMB....

If you have a dumb regulator, and notice the voltage dropping, it is likely a temp compensated dumb regulator. Get rid of it or plan to buy new batteries more often.

If you have a temp compensated alternator or a Hitachi alternator on a Yanmar you really are in dire need of external regulation if deep cycling a larger battery bank.

This is from:

http://forums.sbo.sailboatowners.com...d.php?t=125392

and these, too:

http://www.cruisersforum.com/forums/...on-125843.html


http://www.cruisersforum.com/forums/...or-142083.html