How to connect RV batteries together

ryoung,

Everyone makes mistakes and that was one of mine. As soon as I realized my error I removed the post.

I have never claimed to be infallible or perfect. I'm a zillion miles away from that.

For safety's sake I find it amazing that one doesn't know which terminal to disconnect first and which terminal to reconnect first but can post what a balanced hook up is.

ryoung

The reason why one generally connects the ground wire last, and disconnect it first, is for safety and it's not too hard to understand. Should you accidentally make contact with the frame/chassis with your wrench while tightening other connections and the ground lead is connected, you form a short circuit and could very easily get a nasty burn or worse. If the ground lead is not connected, you may get some sparks and current flowing (through the positive wire and the loads), but it will be much more limited.

For essentially the same reasons, be sure to remove conductive jewelry before working on battery wiring. A short through a ring or watch band is no laughing matter, to put it mildly.

If you're replacing wires and uncertain about making new crimped connections, then check out this website and let them do it for you. Tell the length of conductor, the type and size of terminal, and you're in business. I've bought a ton of boat-related wiring components in the past. Great to business with them:

clicky

Regarding the chicken before the egg discussion going on here, I think you should connect the first wire first. Old timers had a traditional way of thinking that just doesn't make sense sometimes. My father, grandfathers, and other folks I know from previous generations have always said to connect this wire before that one. No consistency, just the same thing they heard from someone else. This issue is as mundane and trivial as a question about lowering the landing gear. Should I lower the landing gear first or pull the pin and let the legs drop first? Should I do a pull test or not do a pull test? Let's all sit around and consume ourselves with worry about every little thing so that we can be the most ineffective folks possible.

What you wrote is not balanced. Here is what it should look like:

2Macs wrote:
I have seen other posts on this forum touting the "balanced method" where you connect positive to positive and negative to negative and use only one battery positive and negative to connect to the RV. I was taught the method explained here, but am curious about the other method. Comments please.

2Macs wrote:
I have seen other posts on this forum touting the "balanced method" where you connect positive to positive and negative to negative and use only one battery positive and negative to connect to the RV.

I think you have a misunderstanding of the balanced method. Go back to page 1.

I have seen other posts on this forum touting the "balanced method" where you connect positive to positive and negative to negative and use only one battery positive and negative to connect to the RV. I was taught the method explained here, but am curious about the other method. Comments please.

Yup, I'd vote for a termination replacement on that wire. If it's possible, you may wish to replace those battery connecting wires with 4 AWG all the way back to the distribution panel and the converter. Multistrand welding wire is a good choice for this as it's inexpensive and is easy to bend to install.
FWIW, I have multiple batteries and a solar system. No wire is smaller than 4 AWG. I figured, if I'm paying enough money to run a good 12 V system, there's no reason to lose power to small wire and voltage drop. All my connectors are crimped and heatshrinked to prevent corrosion and allow for a color schedule between (+) and (-) phases.

God luck with the new batteries!

Yup...just got the RV and that connection was corroded very badly. Just had to clean it off to get things working but definitely going to spend a little more time working on cleaning it up

That terminal is not fixable the corrosion is clear up into the crimped end no amount of cleaning will fix this. You will need a new terminal end put on that.

After that if using FLA batteries I would highly recommend getting the red anti corrosion spray at walmart to eliminate further corrosion.

With DC power Voltage drop is your worst enemy. Add in the corrosion on that terminal and half the wires not even in the terminal your asking for trouble.

The battery will say I'm charged and your convertor will be on overdrive trying to push through the corrosion.

Also if you have any power hungry devices or run any type of invertor you will have significant power losses and constant low voltage alarms with short duration of use of power.

6 gauge 4 gauge it doesn't matter. the smaller the gauge or negative gauge is ultimately the best. I'm running 0 gauge welding cables for my connections and if it wasn't so expensive i'd run 4/0 gauge to eliminate the voltage drop.

I'm full solar and running everything in the rv though if your just using your batteries for lights what you got is fine. However I would still highly recommend replacing that terminal.

Can't really have too large of wire within reason.
www.bcae1.com has excellent info and tutorials about car audio and electronics. Both theory and application. Good reading if you want to understand the what and why of what you're doing with DC current and different components.