12volt batteries in parallel
Replacing words with numbers google TWELVE volt side of life
However here is the ASCII drawing version Euqals sign (==) is wire
Chassis---{12 volt battery}+
. . . . .-{12 Volt Battery}+====Motor home power panel.
Now that is for the puriest
To add a battery lay them as close together as possible.. Using starter cable from your favorite auto place hook NEGATIVE on one to NEGATIVE on the other.
If you can use a BLACK cable for that
And Hook POSITIVE on one to POSITIVE on the other (If possible use RED)
the purist will move the wires currently connected to the positive end of battery one to the positive of battery 2 to balance.
The instructions for six volt are different but I will omit to avoid confusion.
Note.. you can have 1,2,3,4,299,1000 batteries in parallel,, However eventually you reach the cargo limits of yoru RV and the point of ridiculous.
But the process is the same for every battery you add.