12volt/24 volt alternator

[Dockhead]

Originally Posted by Kastrup

Hi skipmac
You have understand the system correct. I think it's unusual to. But that is how the previous owener had build the system. And it's not possible to get i contact with him for an explanation. All the power system is really thought out and professional build. But on this specific point, i can't find out, what he have had in mind.(charge til 24 volt bank)
And yes i'm sure that the two 12V batteries for my domestic systems are wired in series for 24V, i have done my self.

Your suggestion, sound interesting, i have to think it over.

Thanks

There is nothing too complicated about this, and it's not indeed unusual. My boat was delivered this way from the original build.

The 12v system is completely as normal, and is "primary" from the point of view of your engine control panel.

You wire the charge lights as normally -- you have a separate charge light for the 24v system.

The only thing missing is starting up the 24v alternator, since it's not wired to the engine ignition switch like the 12v one is. And this is very simple -- you just need one relay which is activated by the same system which starts up the 12v alternator. There is no problem using 12v for the relay coil, and pass 24v through the contacts.