[Brewfixer]

Anyone know where on a 2001 Shabah (think this would be same for many models) does the alternator feed wire ends up? I have found an orange wire that appears to be 8 gauge attached to the alternator so I assume this is the feed wire. However, the only other place I pick up an orange wire is at the starter.
I am trying to install an isolator and have seperated my batteries but need the alternator feed at the isolator to charge both batteries. no electrical drawings or manuls that cover the charging system that I can find in the forum.

Any help would be appreciated...

[Zackattack]

You have the right wire, that orange wire is the one and only charging wire from the alternator. The point of connection is there at the starter, with that said your alternator will only charge the battery you select on the isolator switch. So, when underway it is good to have on both so you are keeping both powered up.

Good job on your project.

[Brewfixer]

Thanks for the reply... I wonder, is it possible to add a wire from the starter orange terminal to the isolator? That way I would not have to worry about switching over to the both 1 & 2 position? I am running my 2 amps and led lighting, etc from the second battery only. I just think one day after many adult beverages I could forget to switch back to battery 1 and drain both down and have to paddle back to shore.

[Zackattack]

Well, I completely understand the desire for advance caution. As well as the acknowledgment that their likely will be too many adult beverages. ALTHOUGH, it cant be done.

Here is why, If you took one wire to each of the hot leads on the two batteries, you would then be actually connecting them, the very thing you were trying to avoid. The terminal on the Alternator would then become the point at which both batteries were truly in connection, and this could be dangerous since if ones voltage was greater, it may try to pull severe amperage through that very small wire that you have given as a link from the battery that the switch has turned off.

So, in short, the only way that would work would be if there were two charging posts on your alternator that were isolated, and then you could do what you are wanting to.

Your just going to have to put your wife in charge of making sure you are only connected to the stereo battery when your soaking on the hook! At least then you have someone to blame when both go dead.

[Brewfixer]

hmmm... I guess I should have researched the isolator a little deeper. My under standing was by connecting the the altenator to the post of the isolator, the digital circuitry would charge battery 1 as priority then battery 2 and back again.

I will consider the wife option however she is the beer runner and that is demanding enough

[Zackattack]

Well, I probably should have asked if there is something in the design of your isolator switch that made you think that. Is that a feature? That would be nice if it was.

Mine only has three main large leads coming into the switch, one from each battery positive and one outgoing to starter terminal. And the one wire from Alternator that connects at starter. Its very simple.

Whichever you select on switch is what you will use as well as charge or both if selected. Please update me though if what I said is not accurate.

[Brewfixer]

I actually have a digital battery isolator from mastervolt and a switch installed . The best I can describe is that the isolator shuts down the charging of the battery when it is at 100% fully charged and continues to monitor battery charge. It gives priority to the main battery (#1).
I already have my onboard charger (ac/dc) connected to this and thought I could run the alternator in the same manner.

[Zackattack]

I found a schematic here to describe doing what you are proposing, but you need this isolator that I do not have, maybe you do or you should consider adding this to your system to make it what your looking for. Good and simple diagram though.

http://www.boatfix.com/how/Battery4.jpg

You need an ISOLATOR, and now that I know this I will be getting one too. The Isolator switch does not allow the dangerous condition I stated earlier, instead it becomes your path for charging each battery whether on or off from the alternator wire that you remove from the Starter post and bring directly to the isolator and then from there one wire to each battery lead either at the switch or the terminal.

Thanks for this thread, I learned I need another addition to my system.

[Brewfixer]

Yes that is exactly what installed last weekend. But I wasnt sure where the altenator wire ultimately landed. Guess I needed some support before I fried my boat

Thanks Zack!

Here is a schematic I drew up to help install. It's kind of crude but it worked.

[Zackattack]

You got it, you just need to remove the existing wire to starter and take it directly to isolator like your diagram and your good.

Good choice it looks like, which model do you have?