Dual battery issue

[jimy2]

Dear all
Long time snooper first time posting on the fj page .

I have a issue since I setup my dual battery system . I bought the American off-road isolator and an optima yellow top . Got it hooked up at an electricians .as I done know jack about electrics . Since this when I start the car the battery gauge is low and when I rev the engine it goes to normal. Sine then my stock battery has died .i was told be the Electritian it's probably that my stock battery was old .so I bought a red top today but when I start up I have the same issue ?????
I use my secondary batery to run my fridge and other accessory .main runs the winch and spots can anyone help me out

 

[Mtbcoach]

Need more info to help. How it is wired, some sort of schematic is needed.

It sounds like your fridge is draining the system, presuming you are leaving it in your rig and turned on.

You probably have something on draining the battery. Yes, new batteries just die, way too soon for the $$$ IMHO, could be just a timing thing. But, with new batteries, something is draining your system...

 

[jimy2]

Right hear it goes like I said my electrics is bull so please feel free to laugh .

 

[jimy2]

The second photo is what the third wire is connected to the one with ???

 

[jimy2]

 

[jimy2]

Sorry for the multiple post but what there be an issue if both Batteries wear different sizes ?

 

[Mtbcoach]

Here is an illustration of how I would set up a dual battery set-up. The battery size difference shouldn't matter, they should be isolated from each other...