Alternator charging which bank ???

[André R.]

I have installed a new Blue Sea 7650 Add a battery system that came with a switch ON-OFF for 2 banks and a automatic relay.

Blue Sea suggest that the switch goes to the starting batterie that is hook directly to the alternator then to the relay and the house batteries on the other side of the relay. I have been told that I should charge my house bank first then go to the relay, being on a year long voyage down south, the house batteries are more sollicitated that the starting one.

What opinions can we find here. I have a H34, Yanmar 3GM30F, 80Amps alternator.

Thanks

André
S/V Wind Spirit 3

 

[Maine Sail]

I have installed a new Blue Sea 7650 Add a battery system that came with a switch ON-OFF for 2 banks and a automatic relay.

Blue Sea suggest that the switch goes to the starting batterie that is hook directly to the alternator then to the relay and the house batteries on the other side of the relay. I have been told that I should charge my house bank first then go to the relay, being on a year long voyage down south, the house batteries are more sollicitated that the starting one.

What opinions can we find here. I have a H34, Yanmar 3GM30F, 80Amps alternator.

Thanks

André
S/V Wind Spirit 3

Andre,

Please bear in mind those directions are "generic" and that switch system was designed with fishing boats in mind not cruising boats with large house banks. Running the alt to the house bank first will prevent "relay cycling".

I will let Blue Sea explain it in their technical brief:

Relay Cycling Explained- Blue Sea Technical Bulletin

As I have said before, unless your house and start batteries are close to the same size run charge sources to the house bank first...

 

[André R.]

Well explained, thanks for the tip, that answers it all, I think I'll put my alternator to the house bank, I have 450A, when I run the engine it is usually for long periods.
Thanks again.