Warning Buzzer

[ROBDEN]

Hi.

Can anyone enlighten me please?

This started about two weeks ago.

When starting the engine, the warning buzzer goes to let me know that the alternator is not charging. This had never happened before.

Why now?

Easily corrected by just revving a bit harder.

On my previous boat this was overcome by pushing a button, to save the need to rev a cold engine.

How would said button have been wired?

Thanks for any help/advice.

Rob......

[Guest]

FYI - depending on setup they can alert to low oil pressure too, not just charging problems.

[BargeeSpud]

Take it you've checked fan belt tension, battery warning light?

[ROBDEN]

FYI - depending on setup they can alert to low oil pressure too, not just charging problems.

Hi Dog house, oil pressure fine, just the charging dial reads zero untill revved.

 

Take it you've checked fan belt tension, battery warning light?

 

 

Take it you've checked fan belt tension, battery warning light?

Hey Spud. All checked and all ok, thanks

[kevinl]

It its started doing it rather than always been like that then it sounds like something has changed, slipping alternator belt is the obvious one could be failing wires or the alternator on the way out. You are sure it's buzzing for the electrics and not the oil pressure, mine buzzers for both, yould be low il level if it does.

[BEngo]

Hi.

Can anyone enlighten me please?

 

This started about two weeks ago.

 

When starting the engine, the warning buzzer goes to let me know that the alternator is not charging. This had never happened before.

Why now?

 

Easily corrected by just revving a bit harder.

 

On my previous boat this was overcome by pushing a button, to save the need to rev a cold engine.

How would said button have been wired?

 

Thanks for any help/advice.

 

Rob......

The alternator is not exciting via the ignition switch at low revs, but is exciting itself once revved. This is probably a dodgy connection in the link between the battery and the IND terminal, via the ignition switch and alternator warning light as this is the route that supplies the current that gets the alternator going so that the internal windings can take over. Check the connections on the back of the switch, on the back of the warning light holder, inside the warning light holder itself (don't forget the lamp itself) and at the alternator. Make sure they are all clean and tight.

 

It could also be tired or dirty brushes/slip rings- what sort of alternator is it? Lucas ACR and A127 and most car-sized Bosch alternators have the brushes built into the regulator bit. Removing this will allow you to see the state of brushes and slip rings. New regulators are cheap and easy (but more difficult if you have an alternator controller), new slip rings is a specialist job.(Exchange alternator) If it is brushes/slip rings it will get worse.

 

It could be a fault in the buzzer circuit, but I have no idea how that works, and I don't think it is likely.

 

The push button on your previous boat probably either shorted out (bypassed) the warning light or introduced a low resistance in parallel with it. Try shorting across the warning light terminals (the lamp will either not come on or be VERY dim) and then start the engine but don't rev it. If the alternator starts to charge then you could install a 'push to make' button so as to short out the warning lamp.

 

N

[nb Innisfree]

When I fitted our original alternator it started to charge immediately the engine started but after three years daily use it stopped charging (in mid charge!), turned out it was a manual excite alternator and I had to fit a suitable excite switch, I assume the fact that it self excited for three years must have been down to some residual magnetism. So maybe your alt is now working as it should? Many do need revving to self excite.

[ROBDEN]

The alternator is not exciting via the ignition switch at low revs, but is exciting itself once revved. This is probably a dodgy connection in the link between the battery and the IND terminal, via the ignition switch and alternator warning light as this is the route that supplies the current that gets the alternator going so that the internal windings can take over. Check the connections on the back of the switch, on the back of the warning light holder, inside the warning light holder itself (don't forget the lamp itself) and at the alternator. Make sure they are all clean and tight.

 

It could also be tired or dirty brushes/slip rings- what sort of alternator is it? Lucas ACR and A127 and most car-sized Bosch alternators have the brushes built into the regulator bit. Removing this will allow you to see the state of brushes and slip rings. New regulators are cheap and easy (but more difficult if you have an alternator controller), new slip rings is a specialist job.(Exchange alternator) If it is brushes/slip rings it will get worse.

 

It could be a fault in the buzzer circuit, but I have no idea how that works, and I don't think it is likely.

 

The push button on your previous boat probably either shorted out (bypassed) the warning light or introduced a low resistance in parallel with it. Try shorting across the warning light terminals (the lamp will either not come on or be VERY dim) and then start the engine but don't rev it. If the alternator starts to charge then you could install a 'push to make' button so as to short out the warning lamp.

 

N

Thanks BEngo you've just given me an idea.

I don't know the make of the alternator but the engine is a Vetus 4.17.

The manual says that the tickover should be 800 revs.

My tickover is 650 revs and has always been that.

I think that tomorrow I will up the revs to 800 and see how that goes.

[blackrose]

My low pressure warning buzzer sometimes sounds after the engine has been revved hard and then the revs are reduced. Is there any way to stop that? The oil level is correct.

Edited May 24, 2013 by blackrose

[Stormbringer]

Thanks BEngo you've just given me an idea.

I don't know the make of the alternator but the engine is a Vetus 4.17.

The manual says that the tickover should be 800 revs.

My tickover is 650 revs and has always been that.

I think that tomorrow I will up the revs to 800 and see how that goes.

Interesting....my vetus 4.17 also needs a little bit of revs to stop the buzzer and put out the charging light.

I've only had this boat 6 months and if has always been the same.

I thought that it was just set up differently, as my other boat with twin alts self excites on start up...

Ho hum...another little addition to the to do list lol.

 

I'll watch this thread and see how it goes for you...good luck!

 

Cheers

Andy