Would those savvy with electrics take a look please

[Pladdatoo]

I have sketched out a wiring plan which sort of makes sense to me, but I would really appreciate some feedback on whether it is OK or not!

The basics are installing a means to isolate house from starter with the option to conjoin them if necessary - hence the 3 isolators.
The other main components are the VSR and the Nasa BM-2 - hence the shunt.

Whilst I would be happy to hear how people view this set up i.e there are many ways to skin the cat etc, my main request is some guidance as to whether this wiring configuration is correct i.e. would work. Have I missed something etc.
Sorry to all those in advance for the wiring diagram - not my area of expertise so I suspect there are better ways to draw it out, but hopefully it paints a sufficiently accurate portrayal. If it doesn't make any sence, please let me know and I'll try and explain it better.

The best as always.

Pladda

View attachment 44659

 

[VicS]

You dont show how your alternator output will be connected

You show the VSR connected to the switched side of one isolator and the battery side of the other. is this how you intend it to be

I would wire the emergency linking switch so that it links the switched side of the isolators rather than the battery side. That way you can leave a dud battery isolated and run everything on the good one rather than paralleling the good one with the dud one

 

[theoldsalt]

I have always believed that any shunt must be connected directly to the battery "negative" with no other equipment between. If you do not do this then any monitor using the shunt cannot accurately represent total current flow or battery charge state. Is this your intention?

 

[pvb]

Here's a little diagram I did a while ago for another thread. It just needs the shunt added next to the negative connection on the domestic bank.

 

[ghostlymoron]

I've just discovered the bluesea 'add a battery' system. This is very neat and does what you want. It does 'parallel' the batteries in emergency position though which i don't like.

 

[Pladdatoo]

Here's a little diagram I did a while ago for another thread. It just needs the shunt added next to the negative connection on the domestic bank.

Ok this is very helpful......

One question I now have relates to the alternator/battery connection. Would a good way of doing this be with something like a mega fuse bolted to the top of the battery terminal and then running a wire directly to the alternator? If so would 100amp be sufficient and why on the diagram is there a 250amp fuse on the other side?

Appreciate your help and patience!

 

[theoldsalt]

I would not connect ancilliary equipment connected directly to the battery terminal. It is much better to connect them all to a positive bus bar which can then be connected to the battery by a heavy duty cable. In the case of the diagram provided perhaps the commom terminal of the "house" switch could be used instead.
I hate to see lots of individual small wires attached to battery terminals and professional installers do consider it bad practice.

 

[VicS]

Ok this is very helpful......

One question I now have relates to the alternator/battery connection. Would a good way of doing this be with something like a mega fuse bolted to the top of the battery terminal and then running a wire directly to the alternator? If so would 100amp be sufficient and why on the diagram is there a 250amp fuse on the other side?

Appreciate your help and patience!

The diagram is a circuit diagram not a wiring plan intended to show the physical layout
Connect the fuses in the way best suited to your boat and the space available. They should be close to the battery .

The 250amp fuse supplies the starter motor. (as can the one on the house battery).

The 100amp fuse just protects the alternator wiring.