Using isolator to regulate alternator & shore power charge

[loco]

Hi all,
I'm looking to re-wire my boat as the current system doesn't allow me to crank the engine from the domestic battery without the use of jump leads.
I would say my wiring diagram was like Diagram C from the following list:

http://4power.tripod.com/id40.html

It has two cut-off switches - one to each battery, but I would like to use a 1-2-Both switch so I have the option of flipping between the two nice and easily. I also want the two batteries to have a constant trickle charge when the boat's not in use. I was thinking of going for diagram G from the above list, but instead of buying a new charger with dual outputs as per the diagram, to instead wire the shore power charger to the same line as the alternator charging line that goes to the isolator. This way, when I turn the engine off and the charger on, the isolator manages the charging of the batteries and they can have a constant trickle charge when I'm not using the boat.

Think there are any risks/pitfalls to this approach?

Many thanks in advance.

 

[Silvertip]

Re: Using isolator to regulate alternator & shore power charge

If you have to use jumper cables to start your engine as you claim, then the diagram you reference is NOT the way you have the boat wired. If it is, then fix the problem as the starting battery is directly wired to the engine. You either have a bad battery or the connections are loose or corroded. If you add a dual battery switch, eliminate the isolator as it is no longer needed. You can also hook your single output charger to the COM terminal on the switch and then set the swtich to BOTH to charge both batteries at the same time, or BAT 1 or BAT 2 to charge either one individually. Also be aware that an isolator DOES NOT "regulate". It merely serves as a one-way path for current flow.