Dual Battery wiring help

[mrexp21]

The image shows the wiring for dual batteries in vehicle using split charge relay to charge both batteries specifically.

My question is :

Lets consider, main and secondary battery in parallel. Currently, the main and secondary battery will supply current to main load and peltier at once. But, I want to make a system which enables main battery to supply current to main load only and secondary battery to supply current main load and peltier.

[rustydogy]

on your pic draw a hot line from 2nd bat. to main load in the middle of that line place a blocking diode that would isolate the batteries like you want and still keep the charging system you have main bat would control load only when 2nd battery is not charging and 2nd battery would give power when load and piltier and leave the rest of system alone just add wire and block diode in direction of load see this link http://www.islandwaterworld.com/index.htm type block diode in to serch

[mrexp21]

Originally Posted by rustydogy

on your pic draw a hot line from 2nd bat. to main load in the middle of that line place a blocking diode that would isolate the batteries like you want and still keep the charging system you have main bat would control load only when 2nd battery is not charging and 2nd battery would give power when load and piltier and leave the rest of system alone just add wire and block diode in direction of load see this link http://www.islandwaterworld.com/index.htm type block diode in to serch

Hi, thanks for the reply. I have attached an image. Did you mean like this ? If correct, how will the current flow during charging and not charging (assume got load with engine off). If its wrong, can you help me to draw the line. TQ.

[rustydogy]

your split charge relay is what will control witch battery is responsible ,while charging (running ) main power still from main batt, but will be assisted by 2nd batt if charge relay kiks in , Engine off not running (not charging) 2nd battery takes all loads keeping 1st batt isolated , ( still full ) so you can get started agian

[mrexp21]

Originally Posted by rustydogy

your split charge relay is what will control witch battery is responsible ,while charging (running ) main power still from main batt, but will be assisted by 2nd batt if charge relay kiks in , Engine off not running (not charging) 2nd battery takes all loads keeping 1st batt isolated , ( still full ) so you can get started agian

Hi. thanks for your reply. I get your idea, but I need the main battery to supply main load as well. Based on your idea, I've got another simple idea using additional relay in the system.The idea should be able to get the main battery to supply the main load as well when engine OFF. Please have a look at the attached picture. TQ.

[rustydogy]

is about same should work

[mrexp21]

Originally Posted by rustydogy

is about same should work

Hi, thanks for the reply. This means it can work according to my need ?