Alternator settings on a 1996 hunter 336

[Here We Are]

Our 1996 hunter 336, it's a new boat for us. There is a set of switches for the alternator. When would I ever run the engine without having the the alternator switch on? I have been told that it's bad to run with the switch off.
Also, I believe it's bad to switch the alternator battery select switch while the engine is running. Is this correct?
If I don't switch the alternator battery select switch off, when the engine is off, will there be an effect on the batteries? Drain?

[john61ct]

The OUTPUT line from the alternator needs to always have somewhere to go when pumping out amps.

Killing the (field) INPUT stops power production and is safe to do anytime, for example in a situation where a hungry bank is putting significant load on the engine when you need every horse for propulsion in a sticky situation.

There are switches designed to automatically switch off the alt field current concurrent with (actually just before) switching alt output off from one bank to the other.

https://www.bluesea.com/resources/91

The only effect on batteries is the absence of a charge, just as when the engine is off.

[Here We Are]

Originally Posted by john61ct

The OUTPUT line from the alternator needs to always have somewhere to go when pumping out amps.

Killing the (field) INPUT stops power production and is safe to do anytime, for example in a situation where a hungry bank is putting significant load on the engine when you need every horse for propulsion in a sticky situation.

There are switches designed to automatically switch off the alt field current concurrent with (actually just before) switching alt output off from one bank to the other.

https://www.bluesea.com/resources/91

The only effect on batteries is the absence of a charge, just as when the engine is off.

Thank you. There is a switch designated for alternator off. I am trying to locate the info in my manuals.

[smac999]

I highly doubt hunter. (Or any boat maker). Installed any control switches for an alternator. This is a job done by a past owner. Likly himself. For who knows what. You will need to trace everything and figure out what you have.

[john61ct]

Get a boat sparkie to check/do it for you