Aux warning light

[Drayke]

Just had 600w of solar panels fitted, been out and about for 4days and noticed that the AUX warning light on engine control panel keeps on coming on whilst cruising. It seems to happen when the batteries are fully charge. This also happens if I’m plugged into shore power with the battery charger turned on and the engine running, turn off the charger and the AUX light goes out. Anyone got any thoughts on this? Are the solar panels overriding the AUX alternator?

Fred.

[by'eck]

Assuming you are referring to the alternator charge warning light, I suspect its due to the alternators regulator shutting down its output completely rather than just idling. This because an external charge source is raising battery volts above the alternators own regulated limit. Some alternators exhibit this behavior in these circumstances (my Leece Neville 160 amp for example) others don't - its not a fault as such.

Edited August 5, 2015 by by'eck

[chubby]

When i fitted a new alternator last winter i had no end of trouble with my alternatir warning light & buzzer . If my batts are at 100% SOC & solar is operating then when my engines running i have to " create " a load to keep the batts from becoming " full " . Typically i turn on a cabin light in winter but in summer ive found it ok because the fridge is on all day and night .

I Found last winter that i had to completely disconnect the solar altogether whilst the engine was running because otherwise the alternator light would keep coming on which doesn t bother me but the annoying buzzer did very much bother me . Perhaps i couldve disconnected the buzzer but i wanted it to remain functional because one day it may alert me to a genuine problem .

 

My understanding was that the alternator should " idle " or become redundant if the batts were full or if Solar was providing higher voltage but mine most definately does not " idle " - it shuts down completely & this then leads to the warning light coming on .

So my workaround in the end became to disconnect the panels when running engine , reconnect when stationary . Not a chore at all as its just one screw to undo , a maximum of 10 seconds effiort but it drove me bonkers last winter because i thought sonething was very wrong due to the warning light & buzzer operating but it appears ok .

So the post above is correct i think and that some alternators don t idle , they shut off totally and that leads to the light coming on . It shuts down because the solar input is greater or it shuts down cos the batts are full .

im sure some will say im wrong but its definately what goes on in my boat since fitting a brand new alternator last winter

Edited August 6, 2015 by chubby

[bigste]

Maybe an in line on/off switch for solar charging is the simple answer.

[StephenA]

My understanding was that the alternator should " idle " or become redundant if the batts were full or if Solar was providing higher voltage but mine most definately does not " idle " - it shuts down completely & this then leads to the warning light coming on .

 

 

The alternator will idle when the alternator determines that the battery is full if the regulator is working as expected. (which is where long cable runs can cause problems) . The problem is when the terminal voltage is HIGHER than the alternator output. In many boats the indicator line is also driving the split charge relay so it is possible that it will cause that to drop out as well.

 

We've always had a power switch on the batter charger and we never run it when the engine is running.. .I suspect there is a possibility that it could damage the regulator in the long term.

Edited August 6, 2015 by StephenA

[Drayke]

Thanks for the replies, maybe I’ll just disconnect the solar panels when engine is running.

 

Fred

[by'eck]

Thanks for the replies, maybe I’ll just disconnect the solar panels when engine is running.

 

Fred

 

Leaving as is won't do any harm assuming you don't have a warning buzzer running that is. The warning light illuminated is just something to be aware of. A signifcant load on the batteries should pull volts down enough for alternator to kick in again and warning light to extinguish.

[by'eck]

 

The alternator will idle when the alternator determines that the battery is full if the regulator is working as expected. (which is where long cable runs can cause problems) . The problem is when the terminal voltage is HIGHER than the alternator output. In many boats the indicator line is also driving the split charge relay so it is possible that it will cause that to drop out as well.

 

We've always had a power switch on the batter charger and we never run it when the engine is running.. .I suspect there is a possibility that it could damage the regulator in the long term.

 

Well one of my alternators has been exhibiting this behaviour (caused by second alternator) for over three years and 1200 hours. Not sure how long you would want to wait to confirm your suspicion, but I see no grounds to support it.

 

FWIW my suspicion is that the regulator is designed to handle this situation by delibrately causing warning light to illuminate and in doing so make the user aware there is an over-volt situation.

[chubby]

My understanding is that my light and buzzer arent indicating a problem .... theyre just annoying , especially the buzzer which on my barrus shire panel is more a " screecher " than a buzzer . If it were just the light i d be ok .

I was considering the idea of using an isolator key ( decent - not red key type ) to disconnect the solar cable between panels & controller . To be used according to whether the engines running or not .

It went onto my boats to do list in January , & i think it will still be there next January ...

 

ETA : I think Bimble do a decent looking isolator . Try disconnecting the panels maybe . If the probs desist , reconnect & retest etc . If when disconnected all is fine then maybe contact Bimble to ask if thier isolator can be used to make a tidier job of it . If u go down this route can u post back on here .... & i ll do it too !

cheers

Edited August 6, 2015 by chubby

[b0atman]

Thanks for this information its solved my problem too

[Saffa]

Thank you all for the information. I had just had my alternator serviced and noticed my light coming on while cruising yesterday. I remembered this post so I was not too worried. Double checked by disconnecting the panels today and issue solved.