B43 Inverter Buzzing/humming noise

[Larry Witty]

Hello -

Have a 2008 B43 hull 40 which I purchased second hand about a year ago. been very happy with the boat but have 1 annoying problem I would like to resolve. When switching on the inverter I have the following 2 potential issues:

1) Voltage display is low, shows between 102-106 volts

2) Humming noise coming from some sort of auto switch which is encased in a white plastic box behind the cabinet where the radios are mounted

I only have the problem when the inverter is on, no issue with shore power. The inverter seems to power everything just fine and I have not yet check the voltage from one of the outlets with a multimeter yet to see if it is truly low or if the voltage display on the panel is just low - will run this test next time i am on the boat.

The more annoying issue is the humming from what I believe is a transfer switch. I opened up the case and tried to clean the contact points as I read that can sometimes be a problem, but this did not help.

Any guidance you can provide will be appreciated. Also, does anyone know a part number or how to identify this switch?

I have attached a video so you can see the switch and the hum (note that the video is upside down...)

[James Taylor]

I looked at the Beneteau USA site under electrical and did not see the transfer switch on your boat in their images of factory installed equipment ( see below) so I'm assuming the transfer switch was installed as a part of the inverter installation?

You're saying your ac panel is showing 102-106 volts? That would concern me since most electrical items work in the 115-125 voltage range. Maybe the humming could be due to low voltage? Have you checked voltage coming onto boat from dock? Check for appropriate voltage strength going through your power cords, breaker box in starboard locker and breaker box in port side salon cabinet ?  Maybe the transfer switch is bad? Let us know what you come up with. Marine electrician might be in order? If the transfer switch is part of inverter installation you may wish to contact inverter manufacture for part number and guidance?