Wiring 6 & 12 Volt RV Batteries Properly

In my last post I wanted to offer my readers some insight on RV Batteries.  Specifically 6 volt batteries vs a 12 volt battery.  Here is the follow-up article to that post. If you decided that 6 volt batteries are the way you are going to go on your camper. Here is the way to do it properly;

If you are going to buy new 12 Volt or 6 Volt batteries for your RV, it is important to know how to wire them properly so that you do not damage your RVs electrical system. Although this is an easy concept to understand, many people tend to get this wrong. Basically, there are two ways to wire your batteries: in series or in parallel. In RVs where 6 Volt batteries are used, you may need to use a combination of both these methods to get 12 Volt output and increase the amount of total Amp Hours simultaneously. Let’s discuss this further and provide some examples:

Batteries wired in series:

  • With batteries wired in series, the Voltage increases but the Amperage remains the same.
    • Example:  If you take two 6 Volt batteries that have a capacity rating of 220 Amp Hours each and you wire them in series, you will get a total of 12 Volts of power; however, the total Amp Hours will remain the same at a total of 220 Amp Hours.
  • With batteries wired in series, the positive (+) from one battery is connected to the negative (-) terminal of the other.  The remaining free positive (+) terminal and negative (-) terminal are used to connect to your RV.
  • This is how you create 12 Volts from two 6 Volt batteries.

Following is a graphic that represents two 6 Volt batteries wired in series.

six volt batteries wired in series

Take a look at the diagram above. Here we have two 6 Volt batteries wired in series. With the positive from one battery connected to the negative of the other battery you have in essence created one 12 Volt battery out of two 6 Volt batteries. As I stated before, when you wire batteries in series, the Voltage increases and the Amperage stays the same. That is why in this scenario we have 12 Volts output; however, even though each battery is rated at 220 Amp Hours, we are still only receiving a total of 220 Amp Hours. The only thing that has increased here is the Voltage. If in this scenario each battery was a 12 Volt battery, you would have a total of 24 Volts output (which would not be good for your RV).

Batteries wired in parallel:

  • With batteries wired in parallel, the Voltage remains the same but the amperage increases.
    • Example: If you take two 12 Volt batteries that have a capacity of 210 Amp Hours each and you wire them in parallel, the Voltage will remain the same at 12 Volts; however, the total Amp Hours will increase to 420 Amp Hours.
  • With batteries wired in parallel, the positive terminal connects to the positive terminal of the next battery and the negative terminal connects to the negative terminal of the next battery.
  • This is how you increase the total amount of Amp Hours you can get out of your battery bank.

Following is a graphic that represents two 12 Volt batteries wired in parallel.

two 12 volt batteries wired in parallel

In this scenario we have wired two 12 Volt batteries in parallel. As a result, the Voltage has remained the same (at 12 Volts) however the total Amp Hours increases to 420 Amp Hours, which is the total of the two batteries added together.

In my 5th wheel, I used a combination of series and parallel wiring. By taking six – 6 Volt batteries and wiring pairs of batteries in series, I can basically create three 12 Volt batteries that I can then wire in parallel to increase the amount of total Amp Hours that are available. Let’s take a look at how this works:

2 six volt batteries wired in series with a volmeter attached

Take a look at the diagram above. Since this scenario gets confusing for some people I am going to try to make it as simple as possible. This diagram consists of two 6 Volt batteries wired in series.  If you were to take a digital Voltmeter and measure the Voltage from the combination of these two batteries (holding one probe at the free positive (+) terminal and one at the free negative (-) terminal) you would get a reading of 12 Volts. For all intents and purposes, you can now think of this as one 12 Volt battery.  In this scenario the Voltage has increased but the amperage has remained the same.

Now if I want to ensure that I have more total Amp Hours for all my toys, all I have to do is take several of these 6 Volt battery combinations (that are wired in series to give me 12 Volts) and wire them in parallel. Take a look at the diagram below.

six volt batteries wired in series and paralled

In this scenario we have taken six – 6 Volt batteries and wired them in series and parallel to give us 12 Volts and 660 Amp Hours of battery capacity. How did we end up with 660 Amp hours? Remember that each 6 Volt pair of batteries wired in series gives us 220 Amp hours. We have now wired the three pairs of batteries in parallel and when batteries are wired in parallel, the amperage increases. So since each pair produces 220 Amp Hours x 3 pairs = 660 Amp Hours total.

*Don’t mix batteries. If you are going to install new or improved batteries, make sure they are all of the same type (AGM, gel or flooded) and make sure that they are all purchased at the same time and are of the same age. Mixing older batteries with newer ones will most likely limit the longevity of the newer batteries and cause them to degrade or fail sooner.

*Use true deep cycle batteries. Don’t get sold on marine batteries as they are not a true deep cycle battery and are constructed to be somewhere in between a starting battery and a deep cycle battery.

*Before you connect your batteries to your RV or inverter, use a digital voltmeter to ensure that you have wired your batteries properly to output 12 Volts. The last thing you want to do is pump 24 Volts or more through your RVs 12 Volt electrical system accidentally and ruin all of your electronics.

*When installing or working on your batteries make sure you use insulated tools. There is a lot of power stored in a battery. If you accidentally touch both battery posts with your wrench or touch the RV chassis, you could get shocked, burned or even short the battery out and cause it to explode.

*When working on your batteries use protective clothing, safety glasses, and rubber gloves to protect yourself from shocks.

If you have any questions on how to properly wire your 6 volt battery configuration or would rather allow an RV professional do it for you, give your Central PA RV Service Center a call at 800-722-1236.

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The RV Battery Dilemma..

RV battery, RV batteries, PA RV Service Center, Lerch RV, PA RV Dealer

In this corner, the well-known 12 volt battery. In the opposite corner, the challenger, the 6 volt battery….

I decided to start the new year off with a post about batteries. The things that allow us to switch on that light in the middle of the night to find the bathroom.  I recently came across this excellent article comparing 6 volt batteries to 12 volt batteries.  I have several customers that swear by the 6 volt set up. And after reading this article, I might be moved to agree with them.  Let me know your thoughts after you read it…

When I was deciding what batteries to use for my 5th wheel, the first decision that I had to make was 6 Volt vs. 12 Volt batteries. Based on my research, I found that many avid RVers swore by 6 Volt batteries as being superior to 12 Volt batteries. I know that some people may be a little confused by this as they ask, “Don’t most RVs rely on 12 Volts?” The answer is yes, however, you can use 6 Volt batteries if you wire them properly to output 12 Volts. So the next question that many people ask is, “Why would you use 6 Volt batteries instead of 12 Volt batteries? Why not just use 12 Volt batteries?”  If you do some research on the web, you will find endless debates surrounding this topic. In reality, the most important thing to consider is the total Amp Hours you will receive from the batteries in relation to what you can fit into your RV in terms of weight and space. However, there may be some truth to the idea that 6 Volt batteries are superior.

If for instance you use two Group 27 12-Volt batteries that are rated at 105 amp hours each and you wire them in parallel (we will discuss parallel vs. series wiring below), then you will receive a total of 210 amp hours out of your batteries. However, if you use two 6-Volt batteries that are roughly the same size and weight that are rated at 210 amp hours each and you wire them in series for 12 Volts, you will also receive 210 amp hours out of them. So in both situations you are using two batteries and in both situations you are getting roughly the same amount of Amp Hours. So the question remains why choose the 6 Volt batteries over the 12 Volt? The reason is simple when you consider the batteries construction.

Remember from our discussion earlier that a 12 Volt battery is actually made up of six individual battery cells that each output approximately 2.12-2.15 Volts each. Each one of these cells is made up of a lead plate that is surrounded by an acid solution. Generally speaking, the heavier these plates are, the longer they will last and the better suited they are for deep cycle discharges and recharges. Since 6 Volt batteries only contain three cells per battery as opposed to six cells for a 12 Volt battery and since comparable batteries (in terms of amp hours) are roughly the same size (dimensions and weight will vary), the 6 Volt battery is usually constructed with larger plates and therefore tends to last longer in deep discharge situations. Similarly, you may even find that 6 Volt batteries are slightly cheaper than 12 Volt batteries. As a result of the 6 Volt batteries being constructed better and being slightly cheaper, most avid RVers will choose the 6 Volt batteries if they have the space to mount them. If you do some additional research on the web, you can even find people who have tested 12 Volt and 6 Volt batteries side by side. In all of these tests, the results seem to confirm that 6 Volt batteries are superior.

So what are your thoughts? Your choice in batteries is a person choice, both accomplish the job. Regardless if it is a 6 volt or a 12 volt battery,  the lights will be own at the flip of the switch. If not give PA’s RV service department a call…800-722-1236

Safe travels and Happy RVing in the New Year.