Alternator Wiring / Battery Isolator

[cuica]

I'm adding a battery isolator. Does my alternator need energising? I can't tell if there is a D+ terminal...

[cuica]

I added this because the photo wasn't displaying - please ignore...

[jumpshowhigh]

If you go with a perfect switch battery isolator, they're universal.

[cuica]

Originally Posted by jumpshowhigh

If you go with a perfect switch battery isolator, they're universal.

You mean switch between batteries manually? I want the alternator to charge the engine and house batteries at the same time, but without the fear of the house battery draining the engine battery.

I have a Victron isolator. I ran the engine with the alternator attached to the input of the isolator, and put 12V to the energise terminal, but it didn't energise the alternator (ie. no voltage output).

So I wired the alternator back to the engine battery, and now I only see battery voltage at the alternator output (12.6V). Before I tried the isolator I was getting 14V when I revved the engine.

So I wonder if I have damaged the alternator by wiring it to the isolator... There was a delay between the engine starting (ie. alternator spinning) and me connecting the energise circuit. I didn't think this could damage the alternator, but perhaps I was wrong...

I'll take the alternator and the isolator to an electrician and spin it up on the bench to see what's going on.

[jumpshowhigh]

You haven't damaged the alternator, you just haven't wired it properly. That's what's so nice about the Perfect Switch dual battery isolator...it's simple-stupid and performs more efficiently than the Victron unit. That said, if you already have the Victron, it will work for you....it just needs to be wired correctly and i'm sure Victron can help you accomplish that.

[cuica]

I hope you're right, and that I haven't damaged it, but I've wired it back up to the engine battery, and the output doesn't show any more than 12.6V now (battery voltage) no matter how hard I rev the engine...

[jumpshowhigh]

It's an excitation issue. The diodes are not allowing 12 volts to be applied to the alternator to turn the regulator on....or it's not wired correctly.