Isolator wiring question

[cruzin1a]

I did a quick search on Isolators but didn't finad anything related to my issue. Here goes...

I recently bought a 1988 21 Cruisers cuddy. It has a 5.7 350 Merc I/O. It has two deep cycle batteries. There is no selector switch. One is wired to the house and one to the starter. There was a Guest 2401 isolator on the boat that I replaced with a new Guest 2501 isolator because a terminal broke on the old one when I attempted to remove the wires to clean them up.

OK now the issue. I see a feed from the alternator to the isolator which makes sense. There are two more posts on the isolator intended to feed the charge to each battery. I see a wire leaving one of those posts to one of the + terminals on the battery which also makes sense. I do not see a wire leaving the other isolator terminal going to the other battery. What is connected to that other isolator post is an orange wire that I traced back to the engine wiring harness.

1. How can the other battery be charging if there isn't a wire feeding a charging current from the isolator to it?
2. What is the Orange wire coming from the wiring harness to the isolator stud that should be charging the other battery?

I tried my best to make that easy to follow. Any assistance would be greatly appreciated.

 

[nikon]

Re: Isolator wiring question

Are you sure that orange wire isn't going through your wiring harness and then charging your second battery?....If it's working hook it back up the way it was hooked up...If the second battery isn't charging hook the second post up to your second + battery

 

[Don S]

Re: Isolator wiring question

Here is how to properly hook up the isolator.

 

[cruzin1a]

Re: Isolator wiring question

Thanks guys. I see how the auxiliary battery is being charged from B2 on the isolator. What I don't understand is how the cranking battery is being charged. It looks as if the wire off B1 heads back to the starter and then to the cranking battery through the same wire that feeds volts to crank the engine.

 

[bruceb58]

Re: Isolator wiring question

What I don't understand is how the cranking battery is being charged. It looks as if the wire off B1 heads back to the starter and then to the cranking battery through the same wire that feeds volts to crank the engine.

Good observation. That is how it is getting charged.