Alternator Problem?

[TeeELL]

Hi all,

advice requested.

I have an issue, the warning buzzer on my Barrus Shire 'de-luxe' control panel is 'just' buzzing, barely noticeable and the light in the voltmeter is illuminated. Voltage is indicated as normal and my Stirling battery management panel suggests that all is well with the charge to both leisure and starter batteries. Just to help with the analysis - fan belts are OK and tightened correctly, oil pressure is excellent and the engine is not overtemping. Any advice gratefully accepted. Thanks in anticipation.

[RobinJ]

Hi all,

advice requested.

I have an issue, the warning buzzer on my Barrus Shire 'de-luxe' control panel is 'just' buzzing, barely noticeable and the light in the voltmeter is illuminated. Voltage is indicated as normal and my Stirling battery management panel suggests that all is well with the charge to both leisure and starter batteries. Just to help with the analysis - fan belts are OK and tightened correctly, oil pressure is excellent and the engine is not overtemping. Any advice gratefully accepted. Thanks in anticipation.

There is a Manual here!

It indicates that the buzzer will sound when a warning light is illuminated? It includes oil, temperature and charge. So presumably it is your alternator warning light (since it is on the voltmeter) - does it go out when you rev up the engine?

[Tony Brooks]

Hi all,

advice requested.

I have an issue, the warning buzzer on my Barrus Shire 'de-luxe' control panel is 'just' buzzing, barely noticeable and the light in the voltmeter is illuminated. Voltage is indicated as normal and my Stirling battery management panel suggests that all is well with the charge to both leisure and starter batteries. Just to help with the analysis - fan belts are OK and tightened correctly, oil pressure is excellent and the engine is not overtemping. Any advice gratefully accepted. Thanks in anticipation.

 

 

Assuming it is the alternator warning lamp then a faulty diode inside the alternator can cause dim warning lamp illumination and presumably a "just about working" buzzer. However I would expect an accurate voltmeter to show a slightly lower charging voltage unless its an field (auxiliary) diode that has blown. You need to do a maximum current or get the alternator tested.

[Sir Nibble]

Need to know more. One or two alternators? Split charge diode?

Scenario: Engine battery well charged alternator brings it to 14V which is supplied to warning light and buzzer. Domestic battery well discharged, alternator brings it to 13V, result 1V difference between domestic alternator warning light terminal and warning light supply = faint hum.

 

Assuming it is the alternator warning lamp then a faulty diode inside the alternator can cause dim warning lamp illumination and presumably a "just about working" buzzer. However I would expect an accurate voltmeter to show a slightly lower charging voltage unless its an field (auxiliary) diode that has blown. You need to do a maximum current or get the alternator tested.

You can test for this quite easily by comparing voltage readings taken from alternator B+ and D+ terminals. they should be within less than a volt of one another.