12 Volt Wiring Questions

[csichoice]

I have a 2011 Forest River Berkshire 390bh this motor home has two batteries for starting and four house batteries. The four house batteries must be six volt because they have cables running from positive to negative and it is a little confusing for me. I am trying to hard wire in a Dometic portable ref/freezer. The 120 electric was easy but now for the 12Volt? Do I just pick a set of the 6 volt and hook the positive cable to one battery and the negative to the other 6 volt battery? Any help would be greatly appreciated

[Himcules]

you are correct... they are 4 6v batteries. 2 wired serially (positive to negative) to make "one" 12v battery. this is done twice so you have "two" 12v batteries. then the "two" 12v batteries are wired in parallel (positve to positive and negative to negative) to increase Ah capacity. once this is done, you have a bank of batteries that you treat as "one" battery.

you take the negative and positive that are furthest from each other in the bank to provide a balance drain across the entire bank.

take a picture of your battery bay and we can tell you exactly which terminal posts to connect to.

on mine, they were not wired correctly, but instead they used the shortest battery cables they could. made for a neater looking wiring job, but will lead to premature battery failure because of it. it'll work, but it's not right... i'm in the middle of fixing this...

[csichoice]

here is a picture of the batteries thanks for the help. would it be easier to just run the wire into the next bay that has the inverter where the battery cables run too?

[garbonz]

There should be a terminal block somewhere to wire to and that would be best.

[Himcules]

makes no difference where you connect to, as long as you connect "across" the battery bank (furthest from each other negative and positive terminal posts in the bank). in my factory setup, i have 2 sets of connections on my battery bank.

some inverter installation manuals will say to connect to the same terminal posts as the inverter does. this only applies if the inverter was wired to connect across the battery bank. again, my 2013 was not wired that way.

in my battery bay, i see the inverter on one set of posts and the coach's 12v supply on another set. i moved my coach supply to drain across the bank evenly.

btw, no pic?

[csichoice]

For some reason it did not post the picture I will try again tomorrow at work

[garbonz]

Originally Posted by Himcules

makes no difference where you connect to, as long as you connect "across" the battery bank (furthest from each other negative and positive terminal posts in the bank). in my factory setup, i have 2 sets of connections on my battery bank.

some inverter installation manuals will say to connect to the same terminal posts as the inverter does. this only applies if the inverter was wired to connect across the battery bank. again, my 2013 was not wired that way.

in my battery bay, i see the inverter on one set of posts and the coach's 12v supply on another set. i moved my coach supply to drain across the bank evenly.

btw, no pic?

Be nice for the OP to have fuse in the circuit and ZNOT hook direct to the battery don't you think?

[Himcules]

Originally Posted by garbonz

Be nice for the OP to have fuse in the circuit and ZNOT hook direct to the battery don't you think?

Yes, nothing is ever wired to a power source without a breaker or fuse.

OP asked about which battery posts to connect to... Assumed he knew how to wire the rest...

[csichoice]

here is the picture.

[Himcules]

Wow, you have your batteries wired correctly! My factory wiring is wrong.

Your top left is the negative post. Bottom right is positive post.

Good luck

[csichoice]

Thank for your help.