2GM charge light on but battery shows 14.2V

[webcraft]

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The charge light on my Yanmar 2GM control panel is on permanently, but when the engine is running the battery shows 14.2 volts when a multimeter is applied across the terminals.

Should I be worried?

- W

 

[RichardS]

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The charge light on my Yanmar 2GM control panel is on permanently, but when the engine is running the battery shows 14.2 volts when a multimeter is applied across the terminals.

Should I be worried?

- W

14.2V sounds reasonable so the battery will be charging. I don't know why the light would be on permanently though. Does it stay on even at high engine revs?

Richard

 

[Spyro]

maybes aye maybes naw. There's a blue and black wire that should come from the alternator that has an earth on it when the alternator isn't turning this wire should go to one side of the lamp. On the other side of the lamp you should have 12v when you turn on the ignition thus lighting the lamp This should go off when the alternator starts chucking out some amps and you have 12v either side. Is the buzzer on too? Do you have a circuit diagram? It's at the back of the manual. I think there's a link to it on your site.
I've edited this and I think it sounds better now.

 

[lw395]

The light normally goes out because both sides of it are at nominally +12V when the alternator is working.
Something isn't right.

If you load the system, say with a couple of headlamp bulbs, does the alternator still keep up 14V?

 

[VicS]

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The charge light on my Yanmar 2GM control panel is on permanently, but when the engine is running the battery shows 14.2 volts when a multimeter is applied across the terminals.

Should I be worried?

- W

Start by checking the warning light wiring., especially between it and the alternator.

If that all appears OK I think I would then get the alternator checked out by an autoelectrician.

I am thinking along the lines of a bad connection internally so that the field diodes never supply the field current, blown diodes or defective regulator so that the field current is always being supplied via the warning light. If this is so the maximum current output will be much reduced.

 

[mikegunn]

As VicS suggests, sounds like a failure of a current feed from the stator windings to the regulator. This may be caused by failure of the diode trio. If this has happened the alternator will still produce an output, but it will be severely limited because the current flow to the rotor is restricted by the indicator bulb.
Mike

 

[ghostlymoron]

I've got a handbook for 2GM engine cluttering up my book shelf. Does anyone want it?

 

[Daverw]

Yes please, PM sent

 

[Martin&Rene]

My 2003 Yacht came with a 2GM manual, but whilst trying to installing a Sterling Alternator to Battery Regulator I found that there were a couple of errors and misleading parts to the diagram. Thankfully from somebody with a more recent yacht I was able to obtain a different diagram.

 

[Spyro]

My 2003 Yacht came with a 2GM manual, but whilst trying to installing a Sterling Alternator to Battery Regulator I found that there were a couple of errors and misleading parts to the diagram. Thankfully from somebody with a more recent yacht I was able to obtain a different diagram.

There are slight differences depending on what engine control panel you have. The manual I have has different diagrams depending on what type.

 

[Topcat47]

I know it's only a 1GM10, but when the engine's running, the voltmeter reads 13.7v. Stop the engine and it voltage drops below 13v instantly. How far it drops depends on the health of the battery. My service battery is fairly new, but my start battery is quite tired and comes down to 12.4 when full charged.

 

[lw395]

I know it's only a 1GM10, but when the engine's running, the voltmeter reads 13.7v. Stop the engine and it voltage drops below 13v instantly. How far it drops depends on the health of the battery. My service battery is fairly new, but my start battery is quite tired and comes down to 12.4 when full charged.

13.7V is OK for float charging a battery. It's going to take a long time to put any serious charge in.
I have float chargers for my motorbikes. If you discharge a battery to say half way, it takes days at 13.75v to reach full charge.

 

[Topcat47]

My on-board voltmeter is really only indicative. When I had my alternator re-wound, my DVM registered 14.5V but my analogue voltmeter never strays above 14.