[pickupman]

I've had this isolator installed for several weeks now and everything seemed to be working fine. However I went to start my truck yesterday afternoon and everything was dead. Both batteries were reading around 9.6 volts as if the isolator didn't isolate them. After jumping the truck I read the voltage at the battery posts of the terminal and it read only 11.4v? The instructions were next to useless so I could be missing something?

I wired the main batt. directly to the alt so i could drive it until its fixed.

Blue and Purple are the main battery and aux battery (disconected)
Green is the Alt.
Yellow is the exciter for the isolator its attached to IGN hot so it comes on with the engine

I read instructions for another brand of isolator and it mentioned something about an Alternator Exciter wire? It looked like it would be where I put the RED line. It attached somewhere in the circle (and S or D terminal??? no explanation of this in the instructions) running to the output side of the isolator or the + terminal of the battery. Could this be why I don't get 12v out of the posts at the isolator?

 

[therealgeronimo]

The S or D terminal is for an isolator with a diode. It should have an additional terminal for that hook up. If it didn't have a post then the alternator needs to be adjusted. The posts on the isolator should measure at somewhere around 13.7 as it should "eat" around .7v. Check out http://www.mastervolt.nl/downloads/ManualBatteryIsolator11_2003.pdf Maybe that will help. That is where I got the above info.

 

[Forklift]

yeah those dam isolators take like .7 volts when you use them. Thats why Im using a solenoid instead

 

[pickupman]

How would I adjust the alternator output? Does that shorten the life of the alternator? That sounds like my problem as I was only getting 11.5 or so out of the posts which is usless for charging.