Hitachi alternator no output

[Wotname]

Originally Posted by SailBelladonna

I have made some progress and now understand the wiring a bit more. Both alternators are working but we have a constant alarm on the control panel.

In the diagram attached our installation has the "R" cable cut. I understand this is connected internally via a 50ohm resistor anyway and the alternator works without it.

In the diagram below the "L" cable splits into two - one goes to the control panel and another to the "B+" terminal on the alternator - making it permanent live with the battery switch on. When I remove the cable between "L" and "B+" the alarm goes off (what a relief) but the alternator stops charging.



http://sailingbelladonna.co.uk/wp-co...g-original.jpg

It seems to me you have more than one fault and they may be interacting with each other.

The charge lamp and the alternator output should have nothing to do with the buzzer/audile alarm circuit. Likewise there is no need for the changed factory wiring unless there is an internal fault with the alternator.

If it was me, I would disconnect L wire on the alternator and remove the red link. Then I would confirm the audile alarm circuit is working correctly and if it isn't, then fix it. The audile alarm circuit is straightforward. There should be 12V positive on the buzzer +ve terminal (red/black) when and only when the key switch is ON. The buzzer should sound when and only when there is -ve (ground) on any of the three alarmed circuits i.e. cooling water overtemp; low oil pressure; failed rubber seal on sail drive (if fitted). Of course there is low pressure when the engine is stationary. When you have confirmed the audile alarms are working correctly, it is time to look at the alternator issues.

First check the charge lamp is working correctly. With the Key switch ON, the lamp should illuminate when and only when the blue wire is grounded.

Once the charge lamp has been confirmed to be working correctly, reconnect the blue wire to the L terminal on the alternator (leaving the red link disconnected) and connect W terminal (the cut red wire) temporarily to the battery (B) terminal. The alternator should work; if not, it is faulty. If it does work, then remove the wire at W terminal from the B terminal and connect it back to where it should be as per the wiring diagram. The alternator should continue to work correctly.

Once everything works as per the original setup, you can then play around with connecting it you see fit.

[SailBelladonna]

Originally Posted by Wotname

Likewise there is no need for the changed factory wiring unless there is an internal fault with the alternator.

I have removed the split charge diode - would this impact the wiring? I have also added Sterling Alternator Protection devices at the same time. Another user has removed their split charge diode and have the same alarm issues. Equally, I have two engines and alternators and they both have the same issue after removing the split charge diode and re-wiring from 1 to 2 batteries. The alternators are both giving ouput but the alarm is constantly on.

Originally Posted by Wotname

Then I would confirm the audile alarm circuit is working correctly and if it isn't, then fix it.

Thanks for your great help in diagnosing the issue. I will try these tests tomorrow and get back to you - it is getting a bit late here in Papeete.

[Wotname]

Originally Posted by SailBelladonna

I have removed the split charge diode - would this impact the wiring? I have also added Sterling Alternator Protection devices at the same time. Another user has removed their split charge diode and have the same alarm issues. Equally, I have two engines and alternators and they both have the same issue after removing the split charge diode and re-wiring from 1 to 2 batteries. The alternators are both giving ouput but the alarm is constantly on.............

I am only going by the Yanmar engine electrical drawing you posted. Do you have any drawings showing how the two batteries (and/or split charge diode) interfaces to the basic Yanmar alternator?

When you say the alarm is constantly on, what alarm are you referring to?

I have assumed it was the Yanmar audile alarm (buzzer) as shown on the drawing. If so, then the audile alarm should not have any connection to the alternator circuit. As you can see, the Yanmar buzzer (mounted in the engine panel) is only connected to three possible inputs, namely coolant over heat (C.W.), low oil pressure (L.O.) and sail drive rubber seal. If it sounds for any other reason you either have a fault in the wiring or a modification to the wiring.

It is possible there is another audile alarm that has been added over and above the Yanmar engine buzzer. How this is wired is anyone's guess, unless you have a drawing for it.

[Wotname]

Originally Posted by SailBelladonna

............

In the diagram attached our installation has the "R" cable cut. I understand this is connected internally via a 50ohm resistor anyway and the alternator works without it...............

Hmm... Hitachi has made at least two different alternators.

One only has a L terminal (for the charge lamp) and no sense terminal. It is sensed internally off the B+ output via an internal resistor.

The other has two terminals (T connector) where L is for the charge lamp and R is for the sense wire which should be connected to the battery +ve (usually via the key switch). This alternator does not have any internal connection between the R and B+ terminals (AFAIK).

Perhaps the alternator(s) has been changed by a PO.

[Wotname]

I am also assuming in my previous few posts that the charge lamp is the standard Yanmar type which is incandescent - not LED.

As other posters have said, the charge lamp must be incandescent (about 3W) for the alternator to get initial excitation current in the field windings.

[SailBelladonna]

Originally Posted by Wotname

If it was me, I would disconnect L wire on the alternator and remove the red link. Then I would confirm the audile alarm circuit is working correctly and if it isn't, then fix it. The audile alarm circuit is straightforward. There should be 12V positive on the buzzer +ve terminal (red/black) when and only when the key switch is ON. The buzzer should sound when and only when there is -ve (ground) on any of the three alarmed circuits i.e. cooling water overtemp; low oil pressure; failed rubber seal on sail drive (if fitted). Of course there is low pressure when the engine is stationary. When you have confirmed the audile alarms are working correctly, it is time to look at the alternator issues.

Disconnected L wire on the alternator and remove the red link.

Key switch off - 0v on the buzzer +ve terminal (red/black)
Key switch on - 12v on the buzzer +ve terminal (red/black)

Key switch on - red/black to white/blue - 0 volts
Key switch on - red/black to yellow/white - 12 volts - as expected without engine running
Key switch on - red/black to white/red - 0 volts

All as expected so far...

Originally Posted by Wotname

First check the charge lamp is working correctly. With the Key switch ON, the lamp should illuminate when and only when the blue wire is grounded.

Key switch on - blue/black at T plug at alternator gounded and the charge lamp comes on.

All as expected so far...

Originally Posted by Wotname

reconnect the blue wire to the L terminal on the alternator (leaving the red link disconnected) and connect W terminal (the cut red wire) temporarily to the battery (B) terminal. The alternator should work; if not, it is faulty.

This provided no alternator output but the buzzer went off when the engine started.

There was a 12v with the ignition on at the red/black wire at the alternator so I connected this as per the original Yanmar instruction manual. Still no alternator output.

[SailBelladonna]

So I reconnected as per the original factory wiring as per the modified diagram I sent a link to. i.e. disconnected the red/black wire at the T connected in the alterator. The put the red lead joining from the blue/black wire from the T connect to battery +ve.

This makes the alternator work but we get a continuous buzzer with the ignition off.

Then I tested at the buzzer between red/black and other colours:

Ignition off 0v on all terminals except 5v between red/black and yellow/white. THIS IS WHAT MUST BE TRIGGERING ALARM !!!
Ignition on 0v on all terminals except 12v between red/black and yellow/white, as expected.
Ignition on and engine started - alternator charging, 0v between red/black and all other buzzer terminals.

This must indicate that the alternator circuit is somehow connected to the low pressure lamp when the ignition is off but somehow disconnects when the engine starts???

[SailBelladonna]

With the ignition off. I disconnected the low pressure alarm at the engine - yellow/white cable going into the top front of the engine block. I still got 5v testing from the yellow/white cable to the B+ without it connected to the low pressure alarm sensor. I then removed the red lead joining from the blue/black wire from the T connect to battery +ve. The 5V disappeared on the yellow/white connected to the sensor. It seams that 5V causing the alarm is coming from the blue/black lead from the alternator T connector. This is the same on both engines.

[Wotname]

Very quick reply - I will reply in greater detail later as 'time short' at the moment.

First - thanks for reporting your test results in great detail; I will work through the data soon.

Second - some (older) engines have a "low oil pressure switch" in the alternator circuit in order to ensure alternator field is disconnected when the engine is not running. Yanmar has never done this AFAIK. Perhaps a your engine alternator circuits have been modified in a similar way - either intentionally and something has failed in the modification or unintentionally done poorly.

Your results do indicate there is a 'connection' with the low oil pressure alarm circuit and the alternator - again this is not part of the normal Yanmar circuit so the big questions are "WHY and HOW"....

More soon!

[SailBelladonna]

I am a bit of a loss now. Other thoughts:

1) No leds on charge lamp
2) All working OK until I re-wired the boat, changes included:
a) Originally all wired so both engine alterators connected to to split charge diode but removed this and wired to lifepo4 house battery using battery to battery charger.
b) Originally all wired so one battery started both engines but now have 2 starter batteries - each starting its own engine.

I think I am going out of my depth so would appreciate any more input.

[Wotname]

Originally Posted by SailBelladonna

I am a bit of a loss now. Other thoughts:

1) No leds on charge lamp
2) All working OK until I re-wired the boat, changes included:
a) Originally all wired so both engine alterators connected to to split charge diode but removed this and wired to lifepo4 house battery using battery to battery charger.
b) Originally all wired so one battery started both engines but now have 2 starter batteries - each starting its own engine.

I think I am going out of my depth so would appreciate any more input.

OK, this is good to know; I might have missed this point initially. So it is unlikely there were other manufacturer modifications to worry about. Remind me please of the boat design/maker?

Can you post a sketch (rough hand drawn is OK) of the before and after modifications?

We just have to work out where you went wrong .

[Wotname]

Originally Posted by SailBelladonna

So I reconnected as per the original factory wiring as per the modified diagram I sent a link to. i.e. disconnected the red/black wire at the T connected in the alterator. The put the red lead joining from the blue/black wire from the T connect to battery +ve.

This makes the alternator work but we get a continuous buzzer with the ignition off.

Then I tested at the buzzer between red/black and other colours:

Ignition off 0v on all terminals except 5v between red/black and yellow/white. THIS IS WHAT MUST BE TRIGGERING ALARM !!!
Ignition on 0v on all terminals except 12v between red/black and yellow/white, as expected.
Ignition on and engine started - alternator charging, 0v between red/black and all other buzzer terminals.

This must indicate that the alternator circuit is somehow connected to the low pressure lamp when the ignition is off but somehow disconnects when the engine starts???

Originally Posted by SailBelladonna

With the ignition off. I disconnected the low pressure alarm at the engine - yellow/white cable going into the top front of the engine block. I still got 5v testing from the yellow/white cable to the B+ without it connected to the low pressure alarm sensor. I then removed the red lead joining from the blue/black wire from the T connect to battery +ve. The 5V disappeared on the yellow/white connected to the sensor. It seams that 5V causing the alarm is coming from the blue/black lead from the alternator T connector. This is the same on both engines.

Yes, the 5V is causing the alarm to sound when engine is OFF and it is all to do with the Blue/Black wire being joined to the Red wire at the alternator. The L and B alternator terminals are connected to the battery voltage. This is feeding back through the charge light to the buzzer. About half the voltage is being dropped across the charge lamp and about half across the buzzer. These buzzers are very sensitive and will operate on a few volts although not quite as loud as when there is full voltage on the terminals.

Rather than trying to explain in words, I have roughly marked up the previous circuit with the current path. The yellow line is the positive side of the circuit and the green line is the negative side of the circuit. Although it doesn't need proving, removing the bulb in the charge lamp will prove this. The buzzer will be quiet with the charge lamp removed.

I haven't worked out how you have changed things yet but I assuming previously there wasn't any battery volts on the alternator B until the engine was running - BUT my assumption could be wrong.


I would really like to know if the Charge Lamp worked correctly prior to your alterations.

I would also really like to know what the Charge Lamp does now (after your alterations). I have to assume the Charge Lamp doesn't work correctly at the moment.

So my questions are -

1. With the wiring as posted earlier (i.e. Blue/Black wire connected to the Red wire as per the RED link in the drawing and the R terminal Red/Black wire cut), how bright is the Charge Lamp when Key Switch is ON and engine is NOT running?

2. And how bright is the Charge Lamp when Key Switch in ON and the engine is running?

If all was working properly, the answers should be: 1 - Full bright, 2 - Extinguished.
However I think your answers will be: 1 - Extinguished (or dull), 2 - Extinguished.

Meanwhile I will attempt to understand your battery modifications...as post accordingly.

[SailBelladonna]

Originally Posted by Wotname

Remind me please of the boat design/maker?

The boat is a Privilege 37 from 1999.

Originally Posted by Wotname

Can you post a sketch (rough hand drawn is OK) of the before and after modifications?

Here is the initial design before installing lifepo4 and changing to seperate starter batteries.

As is electrical design – Sailing Belladonna

No buzzer issues before I started playing and all charge lights working correctly. The "distributor" refers to the split charge diode.

And here is the design after the electrical changes:

Future state electrical design – Sailing Belladonna

I am wondering if the split charge diode was stopping a voltage coming from the battery to the alternator/fuel pressure sensor when the ignition was off. Removing the split charge diode means the battery is sending a voltage to the alternator and then fuel pressure sensor with the ignition off.

Originally Posted by Wotname

I would really like to know if the Charge Lamp worked correctly prior to your alterations.

All was working correctly before making changes.

Originally Posted by Wotname

1. With the wiring as posted earlier (i.e. Blue/Black wire connected to the Red wire as per the RED link in the drawing and the R terminal Red/Black wire cut), how bright is the Charge Lamp when Key Switch is ON and engine is NOT running?

Ignition off - charge lamp dim and low pressure lamp dim, other lights off.
Ignition on - charge lamp off and low pressure bright, other lights off.
Engine started - all lights off.

Buzzer disconnected on all tests since children are asleep on board...

[Wotname]

Originally Posted by SailBelladonna

..........
I am wondering if the split charge diode was stopping a voltage coming from the battery to the alternator/fuel pressure sensor when the ignition was off. Removing the split charge diode means the battery is sending a voltage to the alternator and then fuel pressure sensor with the ignition off.......

Probably - actually most likely

Originally Posted by SailBelladonna

.....
Ignition off - charge lamp dim and low pressure lamp dim, other lights off.
Ignition on - charge lamp off and low pressure bright, other lights off.
Engine started - all lights off.

Buzzer disconnected on all tests since children are asleep on board...

OK thanks, while it should not be this way, it is as I expected given what has been posted so far.

I am still unsure how the alternator(s) are regulating with the sense wire wire cut but I will work through the above links before shooting my mouth off ().

While this stuff isn't rocket science, it does have to be done correctly so let's work out how to achieve that.

By the way, what was the brown wire mentioned in your opening post

... removing the small brown wire (not the big battery wire) from the alternator +'ve solved the alarm.

. I can't see any brown wire of the Yanmar drawing. Is this wire connected now or not?

More soon...

[SailBelladonna]

Originally Posted by Wotname

By the way, what was the brown wire mentioned in your opening post . I can't see any brown wire of the Yanmar drawing. Is this wire connected now or not?

This was the red wire shown in the wiring diagram.