Hi all, I've got a 30' Itasca Class A. It comes with (2) new 12 volt deep cycle batteries located under the doorway steps. I've build a new battery compartment which will hold (2) more batteries however it is located 6' from the existing batteries. I'll be getting rid of the 12 volt batteries and will install and marry (4) 6 volt deep cycle batteries. What is the best size welding cable to run for that 6' distance between the two separate battery compartments?Thanks in advance!

I used 1/0 welding cable for a 6' run from one bank to the distribution buses. This was for one pair of 6V GC2 batteries. I based the wire gauge on anticipated amperage draw of a 1000W inverter.

It's actually 12' by the time you make the full run. Personally I would run 4/0 to keep the balance of the batteries as close as possible, otherwise your remote stack will never charge to the same level as the ORM location, nor will it share the same discharge load as the OEM. The only way to fix that is reduce the line loss between the two locations, especially since these are all new batteries.But that's just me..

I just installed a four battery bank (500 AH) feeding a 1000W inverter and a 100A charger using 4 gauge cables. Like you two were 6' apart and I used the frame and a 2 gauge 6' cable between the two sets of batteries. This is not a starter system where you need 1000+ amps... just 100 or less. You can balance the hookup by taking off from opposite ends of the two batteries with the + and - cables and SCV... 4/0 for 6' of 100 amps ???:S

Yep.. Buy the best and cry only once

Ivylog wrote:I just installed a four battery bank (500 AH) feeding a 1000W inverter and a 100A charger using 4 gauge cables. Was that 4 gauge or 4/0 gauge. Big difference!

Adding More Batteries to My Class A - What gauge Wire?

45 Replies

BoonHauler
Explorer
Jul 01, 2015
It's a modern miracle ..... :W
Racorman
Explorer
Jul 01, 2015
:B

Thanks guys!!!!!!
time2roll
Nomad
Jul 01, 2015
That is beautiful ;)

For perfection the length of 1-4 & 6-7 will be equal and 3-8 & 2-5 will also be equal.
But don't go crazy over it.
Racorman
Explorer
Jul 01, 2015
smkettner wrote:
You are half way there :B

Yes you can remove the #10 chassis ground and mount as a #11 next to the left battery and connect at #2. 2-5 jumper stays in place.

I love photoshop....... are we there yet with this diagram? :@
time2roll
Nomad
Jul 01, 2015
You are half way there :B

Yes you can remove the #10 chassis ground and mount as a #11 next to the left battery and connect at #2. 2-5 jumper stays in place.
Racorman
Explorer
Jul 01, 2015
BoonHauler wrote:
Still unbalanced .....

Here's a link for you Smart Gauge

You should use method 3, that will fix all your problems.

I'm tryin..... is this what you and smkettner meant by "just move the frame connection close to #2" ? :h
BoonHauler
Explorer
Jul 01, 2015
Still unbalanced .....

Here's a link for you Smart Gauge

You should use method 3, that will fix all your problems.
Racorman
Explorer
Jun 30, 2015
smkettner wrote:
Racorman wrote:
If I do what you recommend:
"either 9 needs to go direct to 3" ......... battery terminal 8 will not have a cable on it?
"OR 10 needs to go direct to 2" ........ then battery terminal 5 will not have a cable on it?

What is the real downside of wiring it up the way I've shown. Would the "balance" be that bad to affect the life or power from the batteries?
The 6' jumper stays in place so the terminal is not empty.

If #10 is a frame ground only... just move the frame connection close to #2.

Otherwise the right hand batteries will wear out faster. Normal use at 20 amps or under it may not matter much. 150 amps into an inverter will matter a lot more.

Instead of moving the #10 frame connection...... how about if I just added a short jumper ground cable from #2 to the frame next to the left side battery group?
time2roll
Nomad
Jun 30, 2015
Racorman wrote:
If I do what you recommend:
"either 9 needs to go direct to 3" ......... battery terminal 8 will not have a cable on it?
"OR 10 needs to go direct to 2" ........ then battery terminal 5 will not have a cable on it?

What is the real downside of wiring it up the way I've shown. Would the "balance" be that bad to affect the life or power from the batteries?
The 6' jumper stays in place so the terminal is not empty.

If #10 is a frame ground only... just move the frame connection close to #2.

Otherwise the right hand batteries will wear out faster. Normal use at 20 amps or under it may not matter much. 150 amps into an inverter will matter a lot more.
BoonHauler
Explorer
Jun 30, 2015
Racorman wrote:
Racorman wrote:
smkettner wrote:
To balance... either 9 needs to go direct to 3 OR 10 needs to go direct to 2.

6' jumper stays in place. No need for wire larger than the main RV feeder.

10 is the ground on the chassis and 9 is to other DC loads in the RV. Those cables are already in place up to the coach battery compartment and their end connections are buried in a mass of wires under the coach.

If I do what you recommend:
"either 9 needs to go direct to 3" ......... battery terminal 8 will not have a cable on it?
"OR 10 needs to go direct to 2" ........ then battery terminal 5 will not have a cable on it?

What is the real downside of wiring it up the way I've shown. Would the "balance" be that bad to affect the life or power from the batteries?

Thanks

I just went through this thread so I'm coming a little late to the party.

If these batteries are wired as shown above you'll destroy that lead set of batteries as most the power will come from them. The second set of batteries will not charge properly as well.