1GM10 charging light.

[Impaler]

My brand new (Nov '17) Yanmar's charging light doesn't come on when I turn on the 'ignition' key. The oil does and goes out when she's started.

I have been given this advice below and wonder if it's true and what is the logic behind it. As advised the light does come on when restarting once she's warmed up. Naturally there is no mention of this in the Yanmar handbook.

"The charging light doesn't come on (on newer models?/on ours) when cold. The alternator isn't "excited" until the engine has warmed up, hence the charging light doesn't come on initially but will if the engine is warm (re-starting). There is a temperature sensor/relay in the circuit. This saves the engine effort when starting on a cold day (alternator not engaged)."

Thanks.

 

[lw395]

The 1GM can struggle to drive a heavily loaded alternator at low rpm from cold.

 

[Topcat47]

The 1GM can struggle to drive a heavily loaded alternator at low rpm from cold.

I can vouch for that. I bought a replacement nominally 35amp alternator for my older 1GM10. When fitted, the engine wouldn't run. On test, the alternator was pushing out 55amps and the cold engine didn't have enough oomph to drive it. The supplier of the replacement alternator was good enough to give me a full refund and refurbish my old one at cost, taking the hit on the postage.

My 15 year old engine charging light comes on with the ignition and goes off when the alternator is up to speed. This also happens on all the family cars from a '68 Morris Minor to a 2014 Toyota. How anything else would work is beyond me. The light is connected to the buzzer, as is the oil pressure warning and engine temperature alarm.

 

[VicS]

I can vouch for that. I bought a replacement nominally 35amp alternator for my older 1GM10. When fitted, the engine wouldn't run. On test, the alternator was pushing out 55amps and the cold engine didn't have enough oomph to drive it. The supplier of the replacement alternator was good enough to give me a full refund and refurbish my old one at cost, taking the hit on the postage.

My 15 year old engine charging light comes on with the ignition and goes off when the alternator is up to speed. This also happens on all the family cars from a '68 Morris Minor to a 2014 Toyota. How anything else would work is beyond me. The light is connected to the buzzer, as is the oil pressure warning and engine temperature alarm.

It only needs a temperature sensitive switch ( open when cold) somewhere in the circuit to interrupt the operation of the warning light and excitation circuit until the engine has warmed up. It would not be the same sensor as the overheat warning light because you would want the alternator to start generating as soon as the engine has warmed up a little. Not generating until the engine overheats would not be a useful feature

The owners manual on the Yanmar website is a Jan 2017 edition so it is possible that Impaler's engine has this feature as a more recent modification. I 'd not like to say but his engine does function as though it does have this feature.

 

[William_H]

I wonder just how consistent this symptom is that the light will not come on before starting but will come on if the engine is warm. Many alternators will begin to charge from residual magnetism without having the initial excitation that comes through the ignition (alternator) light. The light glows from current through the regulator and through the slip rings in the alternator. Any dirt or corrosion on the slip rings might be enough to stop the small current of the lamp. This could then be rubbed off to make a contact once engine is running. However I would not expect that effect to be very consistent.
(quote)
My 15 year old engine charging light comes on with the ignition and goes off when the alternator is up to speed. This also happens on all the family cars from a '68 Morris Minor to a 2014 Toyota. How anything else would work is beyond me.

I assume here the Morris minor had an alternator not a generator or dynamo as of old.
An alternator like any generator gives more power at higher rotation speeds. The speed of the alternator depends on the pulley size as a ratio to the drive pulley. Generally an increase in speed. Now an alternator has a limit on just how fast it can be driven before centripetal forces destroy the rotating parts. (incidentally an alternator is much more robust in nature than an old generator (dynamo) ) So in calculating alternator speed you start from max engine RPM. Obviously a lot higher on a petrol car engine than a diesel boat engine. (about twice as much) . So a boat engine alternator might be geared much faster than a car alternator. Next question is the idle speed of the engine. Somewhat similar I would think. So a boat alternator would start to charge at idle more readily than a car alternator. However in my experience most car alternators will happily charge at idle speed even from start up. olewill

 

[VicS]

I wonder just how consistent this symptom is that the light will not come on before starting but will come on if the engine is warm. Many alternators will begin to charge from residual magnetism without having the initial excitation that comes through the ignition (alternator) light. The light glows from current through the regulator and through the slip rings in the alternator. Any dirt or corrosion on the slip rings might be enough to stop the small current of the lamp. This could then be rubbed off to make a contact once engine is running. However I would not expect that effect to be very consistent.
(quote)
My 15 year old engine charging light comes on with the ignition and goes off when the alternator is up to speed. This also happens on all the family cars from a '68 Morris Minor to a 2014 Toyota. How anything else would work is beyond me.

I assume here the Morris minor had an alternator not a generator or dynamo as of old.
An alternator like any generator gives more power at higher rotation speeds. The speed of the alternator depends on the pulley size as a ratio to the drive pulley. Generally an increase in speed. Now an alternator has a limit on just how fast it can be driven before centripetal forces destroy the rotating parts. (incidentally an alternator is much more robust in nature than an old generator (dynamo) ) So in calculating alternator speed you start from max engine RPM. Obviously a lot higher on a petrol car engine than a diesel boat engine. (about twice as much) . So a boat engine alternator might be geared much faster than a car alternator. Next question is the idle speed of the engine. Somewhat similar I would think. So a boat alternator would start to charge at idle more readily than a car alternator. However in my experience most car alternators will happily charge at idle speed even from start up. olewill

You'd not expect trouble from dirty slip rings on a brand you engine surely ?

A '68 moggy would probably have had a dynamo. Any earlier would definitely . Earliesr car I had with an alternator was a '74 Rover but many small cars still had dynamos long after then.

It would not be difficult to design system that interrupted the filed current. Very simple with an external regulator!

I think the OP should get in touch with the engine supplier and/or Yanmar. If it should not be behaving as it does it needs to be sorted under warranty. OTOH if it is behaving correctly he needs to ask for an updated owners manual.

 

[Impaler]

Thanks for the advice. I’ll need to follow this up with Cornish Crabbers.

 

[VicS]

Thanks for the advice. I’ll need to follow this up with Cornish Crabbers.

Yes, CC should be your first port of call but in the end you may have more joy contacting the UK Yanmar agent directly. ( Barrus )

Funny I am sure I said exactly the same to someone else recently !

 

[Impaler]

Yes, CC should be your first port of call but in the end you may have more joy contacting the UK Yanmar agent directly. ( Barrus )

Funny I am sure I said exactly the same to someone else recently !

He he!

 

[lw395]

It seems to me the OP does not actually have a problem?
My advice would be to fit a voltmeter and check the damn thing is charging nicely once it's been running a couple of minutes. That is what matters.

I went through all this some years ago with one of the lesser known alternator boosters. It had a delay start, otherwise the alternator would load the engine before it was even running! Trying to drive the starter motor from the alternator almost. Didn't help starting, hard on drive belts.

 

[VicS]

It seems to me the OP does not actually have a problem?
My advice would be to fit a voltmeter and check the damn thing is charging nicely once it's been running a couple of minutes. That is what matters.

You are probably right but is not behaving as the manual says it should. If this is due to an update then he should ask for the appropriate updated manual.

If is is due to a fault of some kind then it needs identifying and sorting out before it escalates into a no charge situation ...... remembering that if that is going to happen it will do so immediately after the warranty period has expired

 

[Impaler]

She had a good six hours running on Wed (Lossie to Banff with little wind) and today when switched on both lights came on but not the buzzer, same when shut down. Seems like a dodgy connection? Main thing for me is that the alarm should sound if there’s a problem which it doesn’t appear to be doing. I’ll give CC a tinkle on Monday.

 

[VicS]

She had a good six hours running on Wed (Lossie to Banff with little wind) and today when switched on both lights came on but not the buzzer, same when shut down. Seems like a dodgy connection? Main thing for me is that the alarm should sound if there’s a problem which it doesn’t appear to be doing. I’ll give CC a tinkle on Monday.

Do you have a meter that would allow you to keep an eye on the volts.

That will give you an indication as to whether its charging or not.

Starting from rested you should see the battery volts up around 12.7-12.8 if well charged. They will drop back when starting, obviously, but should soon recover and then rise gradually to 14 -14.4 if the alternator is performing correctly.

 

[Impaler]

She’s definitely charging, both batteries are at 13v rested and the alternator is putting out 14.3. It seems to be a buzzer or connection problem, it tries to buzz when wiggling the key. CC hopefully will help on Monday.

 

[Impaler]

Good response from CC. They say that the charging light does not come on as it did with earlier models. There is probably a buzzer problem. CC contacted Barrus who called me and I've arranged for a local Yanmar agent to give it the once over under warranty. Good result.