What Is The Best RV Battery Set-Up?
If you’ve ever talked to dedicated boondockers or dry campers, you’ve probably heard your fair share of RV battery talk.
Some people are purely 12 volt battery users and others swear by 6 volt batteries and the incredible benefits they believe come from using them.
Related Product: We use the reliable VMAX 100Ah AGM battery (click to view on Amazon) in our RV.
It can be hard to weed through all the opinions when it comes to each style and I’m going to try to lay down the facts in this article.
For the best RV battery set-up for boondocking, I would say lithium with solar power all the way.
But that’s not everyone’s cup of tea, especially for regular weekend campers or people who usually camp with electrical hookups.
So what’s the best RV battery set-up when it comes to 12 volt vs. 6 volt RV batteries?
Like everything that has to do with RVing, that question has a long answer, and it ultimately depends on you and your camping style.
I’m going to start by outlining each kind of RV battery set up and end with my opinion on what is the best RV battery set-up for each kind of camper.
Related: Best Deep Cycle RV Battery (AGM, SLA, 12V, 6V)
The Different Setups
The Traditional 12 Volt RV Battery Set-Up
RVs, travel trailers, 5th-wheels, truck campers, and vans all run on 12 volt power when not connected to electrical hookups. So naturally, you use a 12 volt battery to run everything.
A 12 volt marine deep cycle battery is the most common type of battery used in RVs and the easiest to find in a regular store when you’re on the road.
Even if you buy from a dealer, they will normally install one or two 12 volt batteries connected in parallel.
12 volt batteries are more affordable than 6 volt ones and it’s super easy to connect two of them together to double your amp hours.
Amp hours are a unit of measurement commonly used to give you an idea about how much storage your RV battery is capable of.
Most regular RV/Marine deep cycle batteries will have around 35-70 amp hours in them, but you can buy deep cycle RV batteries with much less or much more amp hour storage capabilities.
See Also: Best 12 Volt RV Lithium Battery Reviews + How To Charge
For regular campers who dry camp on the weekends or full-time RVers who mostly camp with hookups in campgrounds or RV Parks, I recommend a battery set-up that ends up being at least 70 amp hours whether it’s with one or two 12 volt RV batteries.
PROS
- You can run an RV with just one battery. If you have two 12V RV batteries and one fails, you will still be able to run your RV.
- 12V deep cycle RV batteries are usually the more affordable option.
- Easier to find in smaller stores.
- Each 12V battery you connect in parallel will add more amp hours (if connected properly, you can add as many 12V batteries as you want)
CONS
- The more amp hours a 12V battery has, the bigger it is. One 200ah 12V AGM deep cycle RV battery can weigh as much as 114 lbs.
- Can be slightly less durable than a 6V battery, but a high quality 12V battery (AGM, Gel, Lithium) that is not marine deep cycle battery can be just as durable.
- If your RV has a small battery storage area, you may not be able to fit larger 12V high amp hour batteries.
The 6V/Golf Cart RV Battery Set-Up
RVs run on 12V power. So how can you run a 12V RV with a 6V battery? There are two ways to wire batteries together, series and parallel.
When you wire in parallel like you do with 12V RV batteries, you are basically making a larger battery, but the voltage stays the same.
When you wire in series, you are increasing the voltage but not the amp hour capacity.
To read more about wiring multiple 6 volt or 12 volt batteries together for RV use, check out this article here.
Because you need at least 12 volts to run an RV you have to have at least two 6V batteries, there’s no way around it. And if you want to add more batteries later, you will have to add them in pairs.
See Also: Best Portable Solar Panel Charger For RV Camper/Boondocking
Most people will have two 6 volt batteries wired in series for their RV. A 6V 225ah AGM deep cycle RV battery will weigh around 71 lbs.
When you combine two of them in series, you get 12V. But, you still will only have 225ah. Combining two 6V RV batteries only increases the voltage, but not the amp hours like when you wire two 12V RV batteries in parallel.
It’s easier to understand why this happens when you think about it in watt-hours. To find the watt-hours of a battery, you multiply the total voltage by the amp hours.
One 12V RV battery with 100ah will have 1,200 watt-hours. Two 12V RV batteries with 100ah will be 12×200, which equals 2,400 watt-hours.
One 6V RV battery with 225ah equals 1,350 watt-hours. Notice that even though the amp hours on the 6V battery are much higher than the 12V battery, the watt-hours end up being very close.
It’s because you’re multiplying with 6 and not 12 which is a much smaller number. Two 6V RV batteries with 225ah is 12×225, which equals 2,700 watt-hours.
PROS
- Sometimes, 6V batteries can be more durable than 12V ones. For example, 12V marine deep cycle batteries, which are not true deep cycle batteries and not the best option for RVers.
- Easier to manage than large 12V batteries.
- Take up less space.
CONS
- If you have two and one fails you won’t be able to power your RV.
- Harder to find in regular stores.
- Less affordable
6V RV Batteries vs 12V RV Batteries
So, why do people like using a 6V RV battery step-up over a 12V one?
Some people swear that 6V (golf cart) batteries are way more durable than 12V batteries because they are made with thicker internal plates and made to be charged and discharged more than 12V batteries.
This is true with some 12V deep cycle batteries, but not all. If you buy a high-quality 12V deep cycle battery that is not made for running marine engines like AGM, Gel, or Lithium, you will find it’s just as durable as a 6V battery.
See Also: Best Portable Quiet Inverter Generators For RV Camping
The second and most compelling reason for using 6V RV deep cycle batteries instead of 12V ones is the weight. Two 71 lbs 6V batteries with 225ah are way more manageable than one 114 lbs 12V battery with 200ah.
They are also smaller in length and width and more likely to fit into the designated storage area of your RV.
That being said, you can always buy two 100ah 12V RV batteries and wire them together to get the desired 200ah for your RV.
How To Decide Which RV Battery Set-Up Is The Best
When we’re talking amp hours and batteries, all of this only matters if you are a boondocker/dry camper.
If you only camp in RV parks or campgrounds with hookups with one or two nights of dry camping every once in a while, just getting one or two 12V deep cycle RV batteries is going to be the best option.
But for boondocking, the more battery power, the better.
When comparing two 6V batteries with two 12V batteries, I would say 12V wins.
Two 12V RV batteries with 100ah are going to be manageable for one person, fit in regular RV battery storage space, and be way more affordable.
See Also: How To Wire Multiple 12V Or 6V Batteries To An RV
If you get AGM, Gel, or Lithium, the 12V battery will be just as durable as the 6V battery or the difference will be so slight, it won’t matter that much.
The only time I can see 6V being the better option is if you have at least 4 of them. I live full time in a travel trailer. The batteries are stored on the tongue behind the propane tanks.
After doing the math from the measurements of the battery boxes, I will need for the 6V and 12V batteries. I’ve found that I really only can fit two no matter what kind of battery I use.
The 100ah 12V battery I chose as the best one in this article, is only 2.67 inches longer than the best 6V battery from the same article. Using a 6V battery really doesn’t save me enough space to make it worth it.
That being said, if I started storing batteries in the front storage area of my travel trailer, I could store way more batteries, but I still think 4 12V RV batteries would be more worth it than 4 6V RV batteries.
My Choice For The Best RV Battery Set-Up
In conclusion, after taking all the factors into account like space, emergency use, affordability, durability, and weight I think no matter how many deep cycle RV batteries you use, an RV battery set-up using 12V batteries is going to be the best option no matter what kind of RVer you are.
Have any more questions about RV batteries, how to set them up, and 6V vs 12V? Leave a comment below.
Nice article. For those of us still trying to make the decision, I’ve read another article similar to yours That says 6v is the way to go, no question. Ha! Paralysis by analysis.
I agree, the decision between the two can be really difficult because of all the opinions. I think even just a few years ago 6V batteries were technically better but now 12V batteries have gotten much better, especially AGM ones.
For my trailer, I use 12V batteries because most of the time I’m camping hours away from any stores. If I used 6V batteries and one of them stopped working I wouldn’t be able to use any of the electrical in my trailer. With 2 12V batteries, I know that I could still use the electrical if one of them went out. That reason alone was enough for me to choose 12V.
That’s just my reasoning though, I think it’s different for everyone and in the end, both are good options.
Thanks Jenni. One question – you mentioned several times you would choose “good quality” 12v batteries over 6v… do you have advice on what you brands and types you would consider “good quality”? A lot of us would revert to Costco/Interstate batteries, but I’m thinking those are not really what you are talking about. I think you implied they’d be AGM? Thanks again!
Hi Jim,
Yeah, the batteries from Costco are most likely RV marine batteries, so they are not going to be as durable as 6V batteries. But if you choose a 12V AGM or lithium battery that are true deep cycle batteries, they will not only be able to discharge lower but also last longer.
You can find my reviews and suggestions for the best AGM RV batteries here (click to view). If you are curious about lithium RV batteries you can read about those in my article here (click to view). If you go with Lithium batteries make sure the built-in RV charger is capable of charging them. You can read more about that in the Lithium battery article as well.
Hope these articles are helpful, good luck with the batteries.
When you say you have two 100 amp/hr batteries, you really have only 100 usable amp/hrs because of the discharge limit on lead acid batteries. Is this a correct statement?
Thanks
Hello Chuck,
Yes, it’s a correct statement based on the general rule of thumb to keep lead acid batteries above 50% for longevity reasons.
Thanks Jesse. Costco has a 12volt golf cart battery that has “amp/hrs: @20 hours:150. This is on the battery. How many usable amp hours would I he able to use?
Does this mean 150 amps continuous for 20 hours? I’m thinking about using it on my camper without an inverter.
Thanks
Chuck
I believe the @20 hour AH rating is what the battery can deliver in total in 20 hours (@7.5A per hour), so it’s a 150Ah battery.
With the general rule of thumb being to keep these kinds of batteries above 50%, that would give you 75 usable Ah. That’s a great big battery.
Jesse
Yes the 50% rule is for planning purposes based upon your estimated need. However a quality lead acid deep cycle like the Trojan RE can be discharges as deeply as 80% and still give a 1,000 cycle life if cycled this deeply all the time. If only cycled 50% it’s rated cycle life is about 1,600 cycles. Here’s a spec sheet illustrating my point. https://www.trojanbattery.com/pdf/datasheets/T105RE_TrojanRE_Data_Sheets.pdf
As you can see from the chart, discharge rate also material affects battery capacity. This T105-RE will provide up to 200 usable amp/hrs if only discharged at the 100 hr rate and as few as 117 amp/hrs discharged at the 2 hr rate.
A superior battery chemistry is LiFePo-4 which can be discharged even more deeply, at a much higher rate and still deliver it’s rated amp/hr capacity. Of course they have their unique drawbacks, such as not charging them below freezing, and their high price, but their rated life is much longer making most a very good value over time. The best value today, if you are a do it yourselfer is the prismatic cells, particularly the 280ah cells. One can build a battery with over 500 usable amp hrs (and 4000 cycles) including the BMS, for less than the price of a single 100ah Battleborn.
One fact regarding 12V in parallel that was missed is the circulating current if the batteries do not have identical internal impedance or static voltage. For example, battery 1 has 0.25 voltage difference over battery 2. This would cause circulating current flow between the two batteries with the higher voltage battery working to bring up the voltage of the lower battery. Since internal impedance is slightly different that circulating current is constant, eventually running both batteries down to nothing.
Now for RVs that are being charged on a daily basis the detrimental effect is negligible, but RVs in storage would be affected therefore an interconnecting cable should be disconnected. Same effect happens with diesel trucks having two batteries if the truck is stored for several months without use. A caveat to the above described effect is that when batteries are replaced it helps to replace all with identical.
I agree, especially with the newer r.v.’s. There is a lot of parasitic discharge. Although minute singularly, added together they add up. I have an older battery I put in for over winter, and store my agm’s in the garage. The progressive dynamics 45 amp charger keeps it topped all winter with no issues. Over time, before I did this without it plugged in, after about a month or 2, I was getting a low battery alarm. I have never tried to find the length of time I save on battery life.
Is the 20 actually what the battery is rated to provide at 20°c ?
Temperature will affect a battery greatly because it is a chemical reaction.
Thanks for the question, after doing some more reading I found that the RC (rated capacity) and AH (amp hour) capacity are both tested over 20 hours at 80°F (26.6°C). The 20 must mean the 20 hour rate the batteries are tested and rated for.
In all my years of internet research I have never come across so much controversy about a given subject. All I want to do is to increase the usable battery time when I’m at the deer lease or at the beach without hookups. I use two 12 volt batteries in my boat for the trolling motor and they seem to last all day no matter how much I troll around so it seems to me two batteries is better than four. I don’t need an extra 150 lbs. in the front of my RV and I don’t really have the space to give away. I believe the amp hours differences discussed here at minute differences and shouldn’t be the only factor when it comes to making a decision. I want to thank Jenni for her insight and clarification regarding different types of batteries and helping me to decide which way to go.
Thanks for the comment Abel. I’m glad the post was helpful to you.
In your comparison of batteries you use watts, eg 12v x 100ah=1200W, but some batteries have 2 ratings. As an example an amp hour rating of 90 and also a reserve rating of 175. So which do you use to calculate the watts? It is a group 27 12V deep cycle lead acid battery. Different manufacturers seem to use different rating systems, how do you compare apples to oranges?
Hi Bob,
The amp hour rating and reserve capacity rating are two separate things. Usually, when trying to figure out the total number of watt hours a battery has it’s better to go by the amp hour rating number than the reserve capacity one.
But not all batteries have the amp hour rating, some will only tell you the reserve capacity. If you only see the reserve capacity the best way to estimate the amp hours is to divide that number by 2. It’s not going to be 100% correct but it will give you an idea as to how many amp hours the battery has so you can calculate the watts.
👍 article thanks . Will solar panels charge batteries that are totally dead ? Read a few and general answer is no . Batteries need to be +50% (?)
we’re dry camping and have two 6v and not working out great so far . Fixed a problem that I think made the batteries die so we need to get them up again .
Really simple needs – water pump for sinks, toilet and very quick shower and enough to keep gas fridge on .
A solar panel may actually be able to what a battery charger won’t. The newer high tech chargers need to recognize voltage to start charging. A solar panel, like the old school chargers or jumping from another battery, simply routes 12v into the battery. And the battery doesn’t care if the electrons come from the sun or the wall outlet.
Hi Jenni. I have a question for you. I understand that the old 6 V batteries used to be better than the old 12 V batteries. But if you have two interstate 6 V battery 210 amp hours in series for 12 v at 210 AH “GC6 Costco” compare it to two interstate 150 AH 12 V batteries in parallel for 12 v at 300AH. “GC12 Costco” Using the 50%rule you would be comparing 105 ah for the 6s to 150 ah for the 12s. All The batteries are interstate golf cart batteries. Would it not be hard to assume that 150ah with the 2-12s would be better? It is 50% more power than the 105ah of the 6vs. Thanks Gordon.
Hi Gordon,
Thanks for the comment, and I agree the 12v set up is better in most cases. The only downside to consider with the 12 volts is how large the batteries are going to be. Some RVs have limited space and if you can’t fit large 150 ah 12 volt batteries the 6 volts could possibly work better.
I personally use the 12 volt set up for the reasons you outline. If you’re deciding between the two kinds and you have the space for the 12 volts I would go with that set up.
In my case I found that two 6V batteries was a far better option. Two “True Deep Cycle” batteries gave me 235AH @ 20 hour rate. Two 100AH 12V batteries would not only be less total capacity but would also cost me more. Two 6V 235AH batteries set me back $133 each so a total of $266. I couldn’t find a 100AH battery for less than $175 each or $350. Size was the other reason. My RV was designed to house two group 24 12V batteries. The GC2 6V golf cart batteries were almost the same width, shorter in length and only an 1-1/4″ taller. They fit my compartment perfectly. There is no way my compartment could house two 100AH 12V batteries. I couldn’t even fit 2 group 27 batteries let alone a group 31 size battery.
AGM v/s flooded is the other debate. AGM is less maintenance but are a little more finicky about charge rate. They also cost a lot more for less capacity over flooded batteries.
In my case I went with a pair of very good quality Duracell 6V 235AH flooded batteries made by East Penn MFG. Same battery as the Deka. They can be picked up at any Battery Plus store. Any golf cart shop would carry something similar as well. Never “lost” a battery suddenly so not really worried about that. Added a battery watering system so maintenance is a piece of cake.
I agree that there are situations where 12V batteries make more sense. If my batteries were housed inside the living compartment, or in a larger compartment that could hold group 31 batteries, I may have gone the 12V route. If I was made of money and had a new motorhome I may go with LiFEPO4 for the reduced weight, deeper discharge and quicker recharge capability. My MH is a 1992 model Airstream and I’m not going to invest thousands of dollars into batteries.;)
Hey Julius,
Thanks for the insights. Your reasoning sounds perfect for your set up and I agree that if you have limited space, budget, and charging limitations 6 volt flooded lead acid batteries are a great option.
I did the same as you Julius for the same reasons and I’m very happy with my set up as well.
A 6 volt battery for RV is actually a golf cart battery because they have thicker plates inside than a 12 volt deep cycle battery. With a thicker battery plate, the 6 volt battery is able to deliver more long term energy and sustain deep discharging and recharging.
Cycle Life: 850
Amp Hours: 220 AH at 20 Hour Rate
Rate of Discharge: 492 min @ 25 Amps
Do these answers apply to engine batteries? Why 4/ 6volt in my diesel powered puller as opposed to 2/ 12 volt for the engine ? The 6 volts are connected in series and parallel which further confuses me.
Your system is still 12 volt. The only thing engine batteries do is crank the starter. Once the engine is running the alternator takes over. Two 12v batteries are connected in parallel- (+ to +) and (- to -). Same voltage, twice the amperage. If you have four 6v batteries, that’s 24 volts total, so you need to make them into two 12v batteries. So each pair is wired in series (- to ground, + to – of next battery, + of that battery to load) and then the 2 series are wired in parallel. So both – go to ground, both + go to load (the starter, etc).
I grew up in farming and logging country and back then anyone who had a diesel ran two 6 volts. I never knew why but they all seemed to feel it made a stronger system.
I went with Marine 12 volt primarily for cost. Group 29DC at walmart can be purchased for $100 each with 3 year warranty and the stores are everywhere should you have a failure. True that marine batteries aren’t 100% true deep cycle as they do have a cranking amp rating listed but I think this is a good thing in my case. My motorhome has separate house and chassis batteries and should I find my chassis batteries dead I can hit a boost button that cross feeds the two systems and allows it to become one for emergency starting of the engine or generator, so I dont mind the trade off.
Hi Jenni, I have a question regarding 6v battery installation in my RV. When doing 6s in series does it have to be in sets of two? My space is limited and I am wondering if I can put 3-6v batteries in series?
Hi Randy,
When it comes to 6 volt batteries being wired to create a 12 volt system you have to series wire them in pairs to get a 12 volt output that’s compatible with an RVs electrical system.
If you wire 3 6 volt batteries in series you end up with an 18 volt output.
If you have limited space you could get two high capacity 12 volt batteries instead like some of the ones in this review (click to view).
I’ve actually had other campers ask about this before, thanks for bringing it up in the comments, good luck with your RV battery installation.
Find a knowledgeable DEKA battery dealer ask for a true 12 v deep cycle battery GP 27 24 31 depending on your space and ah needs. I have been using East Penn products for years both in my personal stuff and in industrial battery backup systems. The dealer should be able to get you a 12v that will perform as well as the 6v system and be very cost effective and reliable. Weight will be more not only because of 12v but because East Penn plates seem to have more lead in them. Better than most in my opinion based on 30+ years experience.
Awesome advice Edward, thanks for the comment!
I have a different situation going on. Have a cabin near Mt St. Helen’s in Washington State and am using 14 ea. 6 volt deep cell batteries and inverter to run 120v. Just lights, TV’s , chargers and such. We run a generator to charge them and when new, a full charge would last a full weekend +. After 10 years (at about 6-8 weeks usage per year ) a full charge only lasts 3-4 hours now. Not complaining but I need to buy new batteries. I am wondering if I should stick to the 6V or go to something else. The batteries are constantly being run down and then charged up when in use. Space or weight is no problem. Would appreciate any opinions on this. I don’t know much about electricity and am always wondering if there is a newer system out there. Solar is not an option because we are in a heavily wooded area. Thanks!
Hi Jim,
It seems like most people are going with 12 volt lithium batteries when building large battery banks now. I would look into the 12 volt lithium options first.
You can check out this post on 12 volt lithium batteries for a few good recommendations.