Forum Discussion

uncle_ben's avatar
uncle_ben
Explorer
Jul 01, 2013

connecting "in-series" batteries

My travel trailer's batteries were stolen and now that I have 2 new ones to reconnect them, but of course they were already properly connected when I bought the trailer and I never had a need to mess with the wiring before and I don't know how they were connected to begin with. Some of the wires were cut when the batteries were stolen and some were left in-tact. I can easily reconnect everything as far as having the proper tools and supplies to do so, but I don't know which cables go where.

The wires coming out of the trailer are 1 red, 2 white, and 1 black...so first I need to know where each of those should be connected and then also how to connect the 2 batteries to one another in series.

Thanks very much for any help and advice that you can offer!!

Moved to Tech Issues forum from DIY.

18 Replies

  • Another useful piece of info would be the sizes of the wires. If you can't give the AWG sizes tell us which are large and which are small.
  • I never checked on this but can the standard charger nuilt into the inverter/converter charger able to handle charging 2 six volt? or 2 twelve volt tied together?
  • if you are still considering this work yourself then make sure you use a good digital volt ohm meter and pay strict attention to the polarity! The meter will tell you if you are wrong so read the instructions that come with the meter. you may also find some helpful videos on youtube concerning battery and polarity.
  • What year and make of trailer?

    What batteries? I am assuming 6v since you are connecting them in series? WIth two 6's you make a 12v battery by wiring the + on one to the - on the other. The unused posts become the + and - of a 12 V battery. But this of course is NOT the way to hook up a pair of 12v batteries if that is what you have.

    As was mentioned, people have done significant damage reversing polarity, or connecting to 12v's in series and putting 24V to an RV system. Proceed carefully.

    The ground wire(s) should show very low resistance to bare metal on the Rv chassis (with nothing powered up ideally).

    If it is a newer rig with the right kind of converter (what model do you have?) you can power up the converter without a battery connected (not with any disconnected wires where they can short to anything!) and the wire to it will show up at 13.x v most likely, relative to ground. That one goes to the + when hooking to a single 12v battery.

    Jim
  • My advice is if you don't know what you are doing, don't do it. You can really mess things up if you connect them up wrong. Get someone who knows what they are doing to help, or take it to a dealer.
  • If you have 2 6 volt batteries than you will wire them in series, if you have 2 12 volt batteries than you wire them in paralell. the lowest amp battery or the battery with the least abilility to provide optimal power will bring the total output down to what it can handle.


    hope that helps
  • google is the answer.

    http://www.google.com/search?sourceid=navclient&aq=&oq=connecting+batteries+to+rv&ie=UTF-8&rlz=1T4GZAB_enUS513US513&q=connecting+batteries+to+rv&gs_l=hp....0.0.0.44905988...........0.

    if not, take it to a battery place to install and repair the wires.
  • Hi,

    I'd suggest using a continuity test to see which wires go to the ground.

    You might also contact the manufacturer of the rv.

About Technical Issues

Having RV issues? Connect with others who have been in your shoes.24,255 PostsLatest Activity: May 24, 2025