Another Battery Isolator/Automatic Charging Relay Post!

myoung84

Seaman
Joined
May 27, 2008
Messages
67
I will apologize in advance if this has been covered, but I searched and didn't come up with much. I have a NOCO 140A battery isolator that I bought last year and finally hooked it up last week. I'm not sure if I have it wired correctly though. I simply removed the heavy gauge wire from the alternator and taped it off and ran a new wire from the alternator to my isolator alternator input. My two batteries are hooked to the two outputs on the isolator. With the boat running I am getting 14.4V on the alternator output and 13.7V on each battery, which from what I read this is a normal voltage drop across the diodes.

Now my question is, do I have this hooked up correctly? There's another post on the isolator that has nothing on it, do I need to tie an ignition switched wire to this or something else from the alternator?

Also, I have read a lot about the Automatic Charging Relay. Should I just ditch the isolator and go with one of these? My main reason for the isolator was to separate my stereo system battery from the rest of the boat since I was getting pops through the speakers when I operated the trim buttons. I only had the boat out briefly, but it appears the problem is gone with the isolator.

This is on a 2005 Tahoe Q4 with Mercruiser 4.3L carb'd engine.
 

bruceb58

Supreme Mariner
Joined
Mar 5, 2006
Messages
30,454
Re: Another Battery Isolator/Automatic Charging Relay Post!

I would ditch the isolator and get the ACR. That 0.7V drop that you are seeing is normal and will also cause your batteries not to fully charge. I am assuming you would like them to get fully charged, right?

If you do decide to keep what you have, completley remove that wire you have taped off. That is an accident waiting to happen.
 

myoung84

Seaman
Joined
May 27, 2008
Messages
67
Re: Another Battery Isolator/Automatic Charging Relay Post!

It's been ordered, should have it Wednesday!

Anyone want to buy a like-new Noco 140A isolator? :D
 
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