I have two battery compartments in my 5th wheel. However, only one has the batter connections coming from it. An I simply add the second batter and connect to the same posts that my other batter are connected to? I can by the cables from Napa in any length that I want.I am just concerned that by adding a second batter that I will end up with 24 volts vs. 12 volts.I have a 2017 Heartland Bighorn 3575EL.Thanks for the help.-John

Hook two 12v batteries in parallel (doubles capacity but not voltage) by hooking positive to positive and negative to negative (reds together, and blacks together).

Just be sure I am clear, as I not very bright when it comes to DC.I can take the red wire from the second battery and attach it to the same place the red wire from the first battery is attached to the 5th wheel?And the black also, correct?Thank you,-John

So just a further thought, how would they have to be connected to have 24 volts? I don't want 24 volts, I just want to ensure I don't do it incorrectly.Again, thanks a lot.-John

Yes. As long as you connect plus to plus and minus to minus all is good. Depending on how long your connecting cables need to be you can buy welding cable which is very flexible and have ends put on them. They will carry way more current than you will ever need, but sometimes ease of handling is worth it.

2-12’s you’ll want to connect in parallel

Dual Battery in my 5th wheel. | Good Sam Community

MNRon
Explorer
May 27, 2018
Hook two 12v batteries in parallel (doubles capacity but not voltage) by hooking positive to positive and negative to negative (reds together, and blacks together).
prelucir
Explorer
May 27, 2018
Just be sure I am clear, as I not very bright when it comes to DC.

I can take the red wire from the second battery and attach it to the same place the red wire from the first battery is attached to the 5th wheel?

And the black also, correct?

Thank you,

-John
prelucir
Explorer
May 27, 2018
So just a further thought, how would they have to be connected to have 24 volts? I don't want 24 volts, I just want to ensure I don't do it incorrectly.

Again, thanks a lot.

-John
donn0128
Explorer II
May 27, 2018
Yes. As long as you connect plus to plus and minus to minus all is good. Depending on how long your connecting cables need to be you can buy welding cable which is very flexible and have ends put on them. They will carry way more current than you will ever need, but sometimes ease of handling is worth it.
TazFord
Explorer
May 27, 2018
2-12’s you’ll want to connect in parallel
prelucir
Explorer
May 27, 2018
Thank you sir. Napa has the same batter cables that are in the 5th wheel, truck, car and so on. I only need them about 2 feet long. They also crimp on the connectors.
prelucir
Explorer
May 27, 2018
Thanks Taz. I definitely got it now.
2oldman
Explorer II
May 27, 2018
A voltmeter is an essential tool when doing stuff like this.
TazFord
Explorer
May 27, 2018
Sure thing, and not to confuse things more, but you could also use two 6 volts connected in series
Super_Dave
Explorer
May 27, 2018
You don't need standard battery cables but just a couple of short jumpers between the batteries. Buy a couple feet of #6 wire in red and black and get the crimp on connectors for both ends.