My 30A Charles Transformer is definately doing the humming all by itself !
As per Dockhead's experience, when they are lightly loaded, they tend to make less noise.
When I have the A/C running, I can't hear the noise above the din from the compressor
, but when I have just the one transformer active and I'm juicing up the batteries
a lot, you can definatley hear it.
I can just about put up with it as I know it's doing the boat some good (like charging
the batteries), but the Admiral kicks up about it and wants it off if it's making too much noise.
Mind you, she makes me turn off the wind generator
too as soon as she gets into bed
and I keep thinking '8 hours of free juice going to waste'.