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Bill_B

How to wire 2 batteries in series?

18 posts in this topic

New to all this just got a travel trailer.

If I have 2 batteries on my travel trailer how do you wire them together in a series? There are 4 wires 2 black 2 white What is hot? how do I wire them?

:banghead:

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Keep in mind wiring in series will add the voltages of the 2 batteries together (ie 2 6V = 12V, 2 12v=24V) If you have 12V batteries you probably want to go parallel, as the voltage remains the same. Anyhow, series: + of rig to + of battery 1, - of battery 1 has a jumper lead to + of battery 2, - of battery 2 to - of rig. Parallel: "piggyback" the batteries + to +, - to -.

Hope this helps!

Dan

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Ok I guess I need to be more specific and get the terminology correct. Looks like I need to buy new batts so I’m going with 2 12V witch will give me more ban for the buck right?

I will wire in parallel.

Just to make sure the unit has black and white wires NO red.

White is hot?

Black is Negative?

RIGHT??

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The best bang for your buck is to buy two 6V golf cart batteries. You can get them at Les Schwab. They're a little more expensive than a 12V RV battery, but they work so much better. The power just trickles out, so they last a long time. You wanna connect them in a series, like the top diagram posted above, so that the two 6V batteries now form a 12V. The color of the battery wires is not important, but I believe white is normally used for positive, and black for negative. You can probably find good diagrams and instructions on the internet if you Google it..it's a popular thing to do. I did it on my toy hauler, and will never go back to 12V batteries.

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If you have 2 whites and 2 blacks chances are you were wired for 2 12V batteries already, unless the 2nd pair of wires was added for an inverter/generator etc. but the easiest way to be sure what you've got for wiring is to grab a multimeter and ground one lead to the chassis (frame) of the hauler, and meter all 4 leads for resistance. I'm guessing the 2 black ones will get very close to 0 ohms resistance - those would be the grounds. The other 2 will show more resistance and would be the hot leads. If you want to series wire that arrangement just parallel the 2 wires you found to be ground, and parallel the 2 other wires together, then do the series wiring for the 2 lugs that you created. Keep in mind that if you do go the 6V route you'll need to buy a battery cable to go from battery 1 + to battery 2 -.

Dan

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The best bang for your buck is to buy two 6V golf cart batteries. You can get them at Les Schwab. They're a little more expensive than a 12V RV battery, but they work so much better. The power just trickles out, so they last a long time. You wanna connect them in a series, like the top diagram posted above, so that the two 6V batteries now form a 12V. The color of the battery wires is not important, but I believe white is normally used for positive, and black for negative. You can probably find good diagrams and instructions on the internet if you Google it..it's a popular thing to do. I did it on my toy hauler, and will never go back to 12V batteries.

I agree - I bought 2 golf cart batteries at Costco for $75 a piece. I don't need to start my generator in the morning after running the heater all night. Plus they fit in the group 24 battery boxes that came with the trailer.

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Just added batteries to my trailer and I went with two 6V batteries from Sam's Club. 1 year full replacement warranty no questions asked. So, now if I screw up I've got a safey net. $73 220 A/H.

I'd also suggest (if your trailer didn't come with one) a battery monitoring gage. $30 on-line and at a glance can tell you when your batteries get down to 80% - 50% so as not to let them get too low.

The following two links were very helpful in answering most of my questions regarding batters for my trailer.

http://www.ccis.com/home/mnemeth/12volt/12volt.htm

http://bart.ccis.com/home/mnemeth/12volt/12volta.htm

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New to all this just got a travel trailer.

If I have 2 batteries on my travel trailer how do you wire them together in a series? There are 4 wires 2 black 2 white What is hot? how do I wire them?

:banghead:

If they are both 6 volts, I assume you want 12 volts. Run a jumper from + on one to the - on the other. The remaining + and - post is your 12 volts. If they are parallel, ie 2 12V batteries, + to +, - to -.

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OK, further on this subject.

1. What size wire should one use for the connection from one battery to the other?

2. Can you use the interior trailer lights, radio, fan, etc.. when you have the batteries on the charger to top them up? I thought I might have to unplug the batteries to charge them, but maybe not.

Thanks

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OK, further on this subject.

1. What size wire should one use for the connection from one battery to the other?

2. Can you use the interior trailer lights, radio, fan, etc.. when you have the batteries on the charger to top them up? I thought I might have to unplug the batteries to charge them, but maybe not.

Thanks

1. Use 6g wire. You could probably get away with 8g, but I would stick with 6g.

2. What charger are you referring to? The converter in the trailer? Most RV's have at least a 30A converter, which is MORE than enough to run all the 12v appliances and still charge the battery. Check your converter to see the output. Most auto style battery chargers are less than 15A.

And just on another note, the pics showing how to connect batteries in parallel are OK, but not "the best". When connecting in parallel, connect the postive from the trailer to one battery postive, but connect the negative from the trailer to the negative on the other battery negative. This equalizes the resistance in the connections and allows the batteries work in sync better and last longer. If you connect the trailer leads to the same battery it tends to work that battery more and shortens it's life. This also shortens the life of the other battery, as unequal paired batteries tend to only be as good as the worst one. :banghead:

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If you have black and white wires. The black is ususally the hot or positive, while the white is the common or ground.

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1. Use 6g wire. You could probably get away with 8g, but I would stick with 6g.

What about 4g wire? Would that create any problems?

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What about 4g wire? Would that create any problems?

The bigger the wire (smaller the guage #) the better it will be.

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