Revisiting my Battery Isolator

[ChrisGalipo]

Hi everyone!

Today I found out that my coach battery isn't charging... I replaced my battery isolator this summer and I thought the problem was solved. But it's not!

The problem is weird. I made some drawing to explain it to you. What is weird is that when I'm plugged into AC power, I get 14V to the isolator at the side of the coach battery. But when the engine is running, I get 14V too, but it doesn't get through to the battery... I don't understand why when plugged into outlet the 14V would get to the isolator, but when I'm using the engine, the 14V won't get to the coach battery....

It's only working one side. Can anyone tell me what I should looking for??

Thanks!!

[Maineah]

Chris it will not work properly with out the "E" terminal hooked up. The "E" terminal goes to the key switch it needs to have power when the key is on and go off with the key. Your second picture is right that is the way it should act. The "A" terminal will only have power when the engine is running. I'll try to explain the "E" terminal. With an isolator the alternator does not have battery voltage at the "A" terminal as it normally does with out it. It has to see battery voltage at the "A" terminal to charge properly so that is what the "E" terminal is for, it supplies battery voltage to the "A" terminal when you turn the key on. Draw a line on your little box from “A” to 1 and put a arrow pointing at 1 do the same to 2 now draw a line from “E” to “A” and draw an arrow pointing towards “A” This is the direction the electricity flows it can not go towards the arrow point only with the direction it points. So if you follow the flow you can see how the batteries are separated and still charge. Pretty simple aye? There is nothing more then 3 diodes inside that complicated looking box.