Dave Solberg

Are 6-Volt RV Batteries in Series Better Than a Single 12 Volt?

Dave Solberg
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We get a lot of members of the RV Repair Club community asking what kind of RV batteries they should use on their rig. They’re often unsure whether they should opt for a single 12-volt battery or a pair of 6-volt RV batteries in series (equaling 12-volts). The answer to which is better is a simple one: it depends. Okay, so there are some nuances to the dilemma.

To help you figure out which is best for you, in this lesson Dave Solberg teaches you the difference between a 12-volt battery and a series of 6-volt batteries. He talks about the pros and cons of each, and explains why there’s a clear winner based on the type of travel you typically do. With Dave’s advice, you’ll have no trouble deciding the battery option that works for your needs and budget!

Reply to Steve Zoller
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17 Responses to “Are 6-Volt RV Batteries in Series Better Than a Single 12 Volt?”

  1. Jeff Davison

    Is there any advantage to replacing 2 6 V batteries with 2 12V batteries?

    Reply
    • Customer Service

      Hello Jeff,

      Thank you for contacting us.
      You get more power but less amp hours when using 6v batteries. 6v batteries need two combined to create the 12v needed for the systems and they only provide a total of one battery amp hours. This means if you have 2 6v batteries rated for 100 amp hours each, total you only have 100 amps hours. 2 12v batteries combine the amp hours so 2 batteries rated for 100 amp hours gets you 200 amp hours total. This just means you get to use everything twice as long. Going from 12v to 6v cuts your amp hours but does give you more power. They are much stronger and can handle heavier loads. The only time 6v batteries really make a difference is when used on hydraulic systems. They require a lot of power to operate and 6v batteries handle these systems better. If you don’t have hydraulic slides or leveling system, they don’t offer any benefit. If you have 6v batteries and don’t have hydraulics then it is much worth it going to 12v batteries for the extra run time you get.

      Thanks!

      Reply
  2. Jeffery Gannon

    Two 6 volt 200 amp-hour batteries in series have exactly the same capacity as two 12v 100 amp-hour batteries in parallel. The real capacity is the sum of the Watt-hours of the batteries in the bank. Thus 6v x 200Ah x 2 batteries is exactly equal to 12v x 100 Ah x 2 batteries and both banks have 2400 Watt-hours of capacity. The banks will also be about the same volume and weigh about the same for the same battery technology. You can’t beat physics or mother nature.
    Thus

    Reply
    • Steve Zoller

      What the people commenting about are missing is plate thickness. All the batteries have 2 volt cells. So a 6-V battery has three cells with thick walls vs a 12-V battery has six cells with thin walls. When you consider sulfation and longevity, the 6-V batteries are clearly the way to go.

      Reply
      • jimmy cooper

        I used sixes in series for years until I needed to start my roof ac using an inverter on batteries. Thick plates are great for long life and slow discharge when boondocking, but they don’t generate the high amperage as well, needed for an inverter to start an ac compressor as batteries start to discharge. The same principal that automotive batteries have with many thin plates to generate high current, even when partially discharged to crank an engine works for peak current demands in the RV too. Having more plates puts more active material in contact with electrolyte to produce higher current flow than fewer thicker plates since it takes time for the chemical reaction to penetrate a thicker plate with less overall exposed surface area. Where starting and running my AC on inverter is concerned, I need batteries able to deliver peak current rather than many years of service. With proper maintenance in place, the older a battery becomes, the more hard sulfate will have formed on the plates. There is no best one-size fits all in every situation.

        Reply
  3. Mike Morris

    Which is more powerful & lasts longer? (2) six volt batteries in series or (2) 12 volt batteries in parallel? If I go from six volts to 12 volts, do I have to change my converter / inverter to adequately charge the batteries?

    Reply
    • dhagerl

      It seems that is the real question I also would like the answer. Was it ever answered?

      Reply
      • Customer Service

        Hello,

        It depends on the amp hours for the batteries. Amp hours are based on how many hours a battery will last pulling one amp. Say a 12v battery has 100 amp hours, this means it will last about 100 hours running 1 amp. If you were running 10 amps it would only last 10 hours. So if you had 2-12v batteries at 100 amp/h each you would have 200 amp hours total. When you use 6v batteries in series the amp hours don’t increase with the second batteries since it is increasing the voltage. When you connect batteries in series, the voltage combines from the batteries connected. So 2-6v batteries that have 100 amp/h each connected in series would put out 12v 100 amp/h. I recommend checking the batteries you are thinking about purchasing and look at the amp hours. Typically you will get longer lasting batteries when using 12v batteries in parallel since it enlarges the amp capacity. When you have 6v in series, they put out 12v to the system. So if you have 6v batteries now and want to change to 12v batteries, you won’t have to change anything in the system. You just have to make sure to connect the batteries in the correct way to create 12v to the system.

        I hope this helps!

        Dan
        RV Repair Club Video Membership

        Reply
  4. Gary

    You mentioned that you could not use 3 6V batteries. I believe you can using a series parallel configuration. That is have two batteries hooked up in parallel, pos to pos, neg to neg) then hook that combo in series with a third battery.

    Reply
  6. Bert Gunness

    Seems to me that two 12 volt batteries in parallel would have as much capacity as 6 volt batteries in series. The amp hours of the batteries would tell the tale.

    Reply
    • Jeffery Gannon

      I am a retired EE. Two 100 Amp Hour 6 V batteries in series have the sam capacity as one 100 aH 12 volt battery. Two 12 volt batteries in parallel have twice the capacity of the six volt series, but the 12 volt parallel connection is a dangerous fire and explosion hazard. fuses or circuit breakers for each battery should be used to prevent a good battery discharging high current into a failed battery with a shorted cell for example.

      Reply
      • Donald Howard

        When we bought our RV we had two deep discharge RV / marine batteries installed. My question is how do you test an individual battery to see if its working the same as the other one?

        Reply
        • Customer Service

          Hello Donald,

          Thank you for contacting us.

          What is the year, make, and model of your RV?

          Thanks!

          Reply
  7. Albert Crawford(

    So you did not answer the question! Why? Any one can do thst kind of video. Not impressed!

    Reply
    • Customer Service

      Hello Albert,

      We are sorry to hear that your questions have not been answered. Please let us know what your questions are and we can send them to our experts to review.

      Thanks
      Becky RVRC Video Membership

      Reply

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