Wiring Diagram for Re-wire

[grandpiper]

Dear All,

I am currently in the process of rewiring a lot of La Mouette - especially the batteries, switches etc.  What started out as simple as replacing two dead batteries ended up replacing a lot of the existing wiring as it was quite messy at the least, and wrong at the worst.  I am certainly not an expert on electrics and have spent many hours figuring this stuff out with the help of Nigel Calder and Don Casey, whose excellent books are quite invaluable.  The system is to have 2 batteries, the standard 1/2/both/off switch and is a fairly standard and simple design.  I would like to get a voltage sensor relay so that the charging system for both the alternator and the solar panel charges both batteries.

So far so good - however, all the books have the alternator output going straight to the common point on the battery switch, or to no. 1 position on the common switch (more about that later).  On my boat with the YSE8 Yanmar, the alternator has been replaced and has the output wired into the ignition circuit.  I have attached a wiring diagram with this highlighted.

I think this is the way that they used to do this with the alternator sharing the same circuit as the ignition.

Is it ok to remove the alternator output cable from this circuit and have it go straight to the common pole on the battery switch?

This is the wiring diagram that I have drawn up and using.  Once it is all done, I think I might pay someone to audit my electrical system to make sure that all is done correctly, but in the meantime, if you could please have a look and tell me if I have got anything drastically wrong.  I would be very grateful.  Of course nothing is to scale and the components are not in the position that they would be in the boat - it's merely a schematic to get it all worked out.  If it's not viewable on the screen, I have also attached it as a jpeg file.

Thanks in advance

Andrew

[Carl - Elcie Jay]

Hi Andrew,

Not sure about the starting cct but just two questions: 

1. You have no fuse going to the Auxilliary Bus?

2. Aux bus is permanently on Batt #1?  Suggest you move that to the "common" connector. Else you turn off those Aux loads when you move to position"Batt2".

Cheers

Carl

[grandpiper]

Thanks Carl,

The aux bus is connected to Battery One as it is designed to be permanently on eg the bilge pump.  It's connected to the battery side of the switch, so should stay on and pick up the electricity from Battery number 1, even though the switch is moved to "2".

But it should have a fuse however,  at the moment they are relying on the fuse in the line going to the bilge pump and the fuse in the head macerator.  When I bought the boat, it didn't even have a fuse in the bilge pump circuit.  The loads aren't great, I think the bilge pump is 10 amps and the head motor about the same - therefore a 20 amp fuse?

cheers

Andrew

On Wednesday, July 5, 2017 at 12:12:16 PM UTC+10, Carl - Elcie Jay wrote:

[Maeling]

On Maeling I put a 25amp fuse on the cable going to my Bus bar, if something blows that it is serious, I think cars have a similar master fusible link.  I have a similar setup to you for the bilge pump.

Geoff Raebel