Single wire alternator

[Flukinicehole]

I have a 89 mercruiser 5.0 with twin batteries.My question is with the single wire alternator do I run a wire from alternator to both batteries? Or run it to one battery and connect the batteries together?If I do it this way it kind of defeats the purpose of the battery switch no? Thanks for any help.

 

[Reel Poor]

Re: Single wire alternator

[color=lt blue]It really should be wired with an isolator. Isolators keep your alternator from working overtime.

Here is a wiring diagram of a correct setup.

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[Flukinicehole]

Re: Single wire alternator

Thank You.

 

[ron7000]

Re: Single wire alternator

You would just connect the output wire from the alternator to a point in the hot side of the electrical system AFTER the battery switch, in the pic it would be that line from the switch to the S. I guess the S refers to solenoid for the starter, that is usually a good point.
Doing it this way doesn't defeat the purpose of the battery switch. when the switch is on both, the alternator will charge both batteries. When the switch is on 1 or 2 then only that battery is getting charged.

 

[Bondo]

Re: Single wire alternator

I've Never Seen an Altenator wired Directly to a Battery,..... Ever........

The Alt.'s Hot Wire goes to the Starter,..... To get to the Battery........

 

[rodbolt]

Re: Single wire alternator

that Isolator setup is the ticket.
altenator can charge either battery or both independantly regardless of switch position.
its how we wire most single engine rigs with 1 starting battery and a house battery.