House and chassis battery not charging

[lazydazeCo]

Hi all, i am running into a road block. My 1989 lazy daze, with a 89 chevy g-30 5.7 liter v8 is not charging the house or main batteries. I tested and replaced my alternator, I have tested the solid state battery isolator and it seems fine. When I bypass the isolator and hook the alternator directly to the battery, it charges, if the isolator is hooked up, it stays at 11.8 amps and falls. What could I be missing here? Any help or ideas would be great!
Thanks!

[twinboat]

You need a battery sense wire to the alternators regulator. If your using the newer single wire alternator, I don't think it will work.

The diode isolator blocks battery voltage from getting to the " built in " voltage regulator.

Google some isolators to see if there are types of wiring to get it working.

[nothermark]

I'm trying to figure out why you are running the alternator to engine battery through the isolator. That makes me wonder if something is wired wrong.

[twinboat]

Here is some info for Delco alternators.
https://www.etrailer.com/Accessories...a/DW08768.html

[twinboat]

Originally Posted by nothermark

I'm trying to figure out why you are running the alternator to engine battery through the isolator. That makes me wonder if something is wired wrong.

Nothing is wired wrong. It is a diode isolator that takes the alternator output and splits it to both banks. They were very common in RVs and boats, up until the late 90s.

Google " Battery Isolator ". They explain how it works.

It is NOT an isolation relay ( solenoid ) that is used in today's units to inter -connect the battery banks.