Battery isolator/alternator problem.

[MGnoob]

I finally hooked up my battery isolator.
The alternator won’t generate any power.

 

when I have the alternator connected to the alternator post on the battery isolator and the main battery on one of the battery posts on the battery isolator. No power is generated.

I do have all the grounds for all the batteries run through the current sensor “amp clamp”.

 

I need to know how to make the battery control module “BCM” recognize the primary battery while hooked to the isolator.

 

if I run a cable from the main battery in its factory configuration to the alternator post on the battery isolator everything works.

 

but the issue is that defeats the purpose of the battery isolator. It would use the main battery to charge my other batteries also drain my main battery when the vehicle isn’t running.

 

I don’t want to install a relay for the reasons listed above.

 

how do I get this to work?

 

and yes, I have a nine-year-old post on this. I finally just got it done. I just have figure this issue out and connect my light bars. It’s just a matter of hooking up a few wires..

 

 

Edited June 18, 2025 by MGnoob
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[MGnoob]

I solved the problem. I bought a modern non-diode isolator that has connections to energize the alternator. Other than that, you have to run the alternator to the input on the isolator, but you have to leave the other end of the stock alternator wire connected to the battery and its original Location. Inside the factory harness it must tell the BCU something.

 

The new isolator is physically much smaller .. Which makes the install much more realistic and has minimal voltage drop which is a huge plus.