Voltage and gauges

[Cavalierbond]

volt gauge normally showed 12-14 but on last trip was at max ( 16 ) and then all gauges went dead for 5-10 mins .. then came back and showed 12-14 again .. engine still ran .. ???

 

[gordmac]

Alternator on the way out?

 

[Cavalierbond]

Thanks ... thought it strange it goes to max .. then dies then is fine for hours

 

[gordmac]

The alternator should give about 14.5v, much over that for any length of time is not good for the battery, it can boil.

 

[Cavalierbond]

Ah ok ... it just happened on one voyage..

What do you reckon would make all the instruments die .. temporarily?

 

[simonfraser]

no voltage would do it

did the cabin lights / fridge go too ?

 

[Cavalierbond]

Not sure as we was at 20 knots

 

[Nito]

I'd keep an eye on the voltage regulator. Maybe it's on its way out thus overcharging and perhaps some high voltage protection or thermal breaker came in to prevent damage until it cooled down. Do you have auto resetting breakers?

The voltage regulator, or rectifier as it is also known, is usually attached to the alternator and generally available separately without requiring a whole new alternator. I'd also check all connections around the alternator regulator and battery.

If you can do it easily, run some voltage tests with the engine off, engine running and engine at high idle and see what readings you get at the battery. If you start seeing much over 14.5v I'd say it's a good chance you have got a rectifier issue.

Do you have an alternator sensing circuit fuse? There is a box on our boat in the engine room marked thus, might also be a good place to look/check.

Good luck,

 

[Cavalierbond]

Thanks very much