Should you wire your RV’s batteries in series vs parallel? That’s a great question, and knowing the correct answer is really important. If we had a dollar for every time we’ve been asked, “Are RV batteries wired in series or parallel?” we’d have enough to fuel our GMC Sierra for quite a road trip! 😂 However, there isn’t a one-size-fits-all answer, as it depends on several different factors. There are situations in which you’ll want to wire your batteries in series, and there are other situations where wiring RV batteries in parallel is more effective. And, of course, the series-parallel configuration is also very common.
For example, if you were to ask us how to wire two 6-volt RV batteries, we’d give you one answer. However, if you were to ask us how to wire four 6-volt batteries for RV use, we’d give you a different answer. If you said you wanted to wire several 12-volt batteries together, we’d give you yet another answer. Three different answers for three different situations.
And to further complicate things, we’d need to know your goal in wiring your batteries together. Are you looking to increase the capacity or voltage of your battery bank? The answer to that question takes into consideration the devices and appliances you’re powering and is key to knowing how you want to connect your batteries.
In this post, we outline all the particulars so you have a guide to follow based on the type and number of batteries in your RV, as well as your intended purpose.
Wiring RV Batteries in Series vs Parallel: What’s the Difference?
Whether you’re working with flooded lead-acid (including gel or AGM) or lithium batteries, the following information will apply (see our RV battery guide for more on RV battery types):
The difference between connecting batteries in series vs parallel is that connecting in series will increase the voltage of your battery bank, and connecting the batteries in parallel will increase your battery bank’s capacity (amp hours).
Those are the two simplest ways to wire batteries together. But a third option exists for wiring sets of batteries together in a series-parallel connection, which would increase both the voltage and the capacity. Let’s examine how to wire batteries in each of these three ways and what the results would be.
Note: Whether you wire your batteries in series or parallel, all the batteries in the bank must be the same voltage and capacity rating. Mixing voltages and capacities can damage your batteries.
Wiring RV Batteries in Parallel
Connecting RV batteries in parallel is a straightforward process. A parallel connection connects the batteries’ terminals, positive (+) to positive (+) and negative (–) to negative (–). When you connect batteries in parallel, you increase your battery capacity (which means you increase the amp hours), but the voltage stays the same.
So, let’s say you have two 12-volt batteries, each with a capacity of 100 amp hours (Ah). To wire them together in parallel, you’ll connect the positive terminal (+) of the first battery to the positive terminal (+) of the second battery, and you’ll connect the negative terminal (–) of the first battery to the negative terminal (–) of the second battery.
This illustration shows two batteries wired in parallel: positive to positive and negative to negative.
In doing this, you’ve increased the total capacity of your battery bank to 200Ah, but the voltage will remain at 12 volts. If you were to add a third battery, you’d have 300Ah @ 12V. Adding a fourth battery would give you 400Ah @ 12V, and so on. Thus, wiring your RV batteries in parallel combines multiple batteries to increase the available power that can be stored, without increasing the output voltage.
Here’s an illustration of three batteries connected in parallel:
With three batteries connected in parallel, you’re tripling the capacity while the voltage remains the same.
Pros of Parallel Wiring
The benefit of wiring a battery bank in parallel is that you’re increasing the capacity of your system with each battery added to the bank. This means you’ll have more power available for longer, the more batteries you add to the configuration. Another benefit of connecting your batteries in parallel is that if one of the batteries dies, the other batteries can still provide power to your RV (so you won’t be stranded), but the lifespan of the remaining batteries will be significantly reduced if you don’t replace the dead unit.
Cons of Parallel Wiring
The primary disadvantage of wiring batteries in parallel is that the charging time increases. Without also increasing the capacity of your RV’s battery charger, it may become impractical to completely recharge your battery bank if it gets too large.
Wiring RV Batteries In Series
Connecting batteries in series accomplishes the opposite goal: a series connection increases the resulting voltage (you add the voltage of each battery in the series), but doesn’t increase the capacity. For example, this is often done with two 6-volt, deep-cycle (“golf cart”) batteries. You use this technique when you want to combine two lower-voltage batteries (of the same voltage) into one larger, double-voltage bank.
To wire batteries together in series, you’ll connect the first battery’s positive (+) terminal to the second battery’s negative (–) terminal.
When you wire two batteries together in series, you’re doubling the voltage while the capacity remains the same.
Wiring two 6V batteries in series creates a set that acts like a single, larger-capacity, 12V battery. Similarly, if you were to wire two 100Ah 12V batteries together in series, you’d end up with a 24V battery bank with a 100Ah capacity. You’ve doubled the voltage, but the reserve capacity remains the same.
Here’s an illustration of three batteries connected in series:
When you connect three batteries in series, you’re tripling the voltage while the capacity remains the same.
You might wonder why you’d want to connect your batteries in such a way that the amp hours wouldn’t be increased, but the voltage would.
Pros of Wiring in Series
Using a pair of 6V deep-cycle lead-acid batteries wired in series to create one larger 12V battery typically provides greater capacity than a single 12V battery. That’s because 6V batteries typically have greater amp-hour capacity than their same-size 12V counterparts due to thicker and more robust lead plates.
Another benefit to wiring your battery bank in series is that you’ll be able to use lighter, thinner, more flexible, and less expensive wire. There will also be less voltage drop in your system when it’s under load.
Cons of Wiring in Series
When you wire a battery bank in series, you can’t obtain lower voltages from that system without a converter (i.e., if you wired two 12V batteries in series to create a 24V bank). Therefore, either all of your devices and appliances must be able to operate at the higher voltage, or you’ll be required to use a converter to supply the lower-voltage appliances.
Wiring RV Batteries in Series-Parallel
Wiring sets of batteries in series-parallel sounds a bit more complicated. Still, once you understand that you’re dealing with connecting (in parallel) sets of batteries that are then wired in series, it becomes clearer.
For example, this is where you can combine four 6V batteries to create a single large 12V battery bank. To do this, you’d wire two pairs of 6V batteries together in series (making each pair 12V), and then wire those two sets together in parallel, to combine their capacity.
When you wire four batteries together in series-parallel, you wire two batteries together in series (+ to –), creating a set. You then wire the other two batteries together in series (+ to –), creating a second set. Finally, you wire the two series sets of batteries to each other in parallel. (See a video demonstrating this on YouTube)
Likewise, you could wire two 12V batteries together in series, resulting in 24V, and then wire that first set in parallel with another set of 24V batteries.
The important thing here is to consider each set of series-wired batteries as one battery. Then, you bring together a second set of batteries with the same voltage as the first and wire the two sets together in parallel.
The advantage of wiring in series-parallel is that you’re increasing both the voltage and the battery bank’s capacity.
RV Batteries in Series vs Parallel: Which is Better?
Generally, the choice between connecting your RV batteries in series vs parallel depends primarily on the devices and appliances you’ll be powering. As you’ve seen above, wiring your RV batteries in parallel involves the simplest wiring while maintaining the same voltage. However, for systems that require more power and for larger solar systems, using series connections to provide more voltage is usually the best approach.
If you want to wire your battery bank to increase both voltage and capacity, you’ll want to opt for a series-parallel wiring system.
Remember that it’s always best to use batteries of the same chemistry, age, voltage, and capacity ratings when you’re creating a battery bank. And if you’re considering doing any work on your RV’s battery bank, you may need a couple of tools like the following:
- Backlight/Large screen LCD display/NCV/Live wire test
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- 【What You Get:】 10 Pcs per pack of 2/0 Guage (AWG) 3/8" ring terminals, copper lugs closed end termination ring terminals with 10 Pcs 3:1 Dual...
- 【Quality Material:】 The TKDMR bare copper battery cable ends are made from 100% annealed copper with special treatment surface for corrosion...
And if you’re re-doing your battery bank, consider upgrading your RV’s batteries to lithium with Battle Born Batteries:
For more on matters related to your RV batteries, check out our posts entitled “Should I Disconnect My RV Battery When Plugged Into Shore Power?“, “What is an RV Battery Disconnect Switch?“, or RV Battery Guide: House, Chassis, Lithium & More.
And if your RV’s electrical system often leaves you scratching your head, confused? Check out our article, “RV Wiring For Dummies: Don’t Be Shocked By What You Don’t Know” to learn more.
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Jay
Monday 30th of June 2025
Look closely at the pictures and note that the positive and negative cables do not come off of the same battery. If you put the negative and positive cables on the same battery, unlike what's shown in the pictures, you will be pulling out from or be charging mostly to and from that battery and not both equally because the flow of electrons will be along the shortest path.
It gets worse. In a daisy chain of MORE THAN 2 batteries, let's say lined up one next to each other, the positive would come from the battery on one end and the negative from the battery on the other end. Furthermore, the positive and negative cables interconnecting more than 2 batteries all need to be the same length in order for the path to each battery to be the same. If you only have 2 batteries, none of this applies. Let me explain.
For example, I had 4 Battleborn 12V lithium batteries but I could only fit 3 in the original battery compartment. The 4th battery was placed in an adjacent compartment right next to the inverter. The first 3 batteries were right next to each other, but the 4th was not and its distance from battery 3 required 48" of battery cables. That meant that 48" long cables were required from batteries 1 to 2, 2 to 3 and 3 to 4. What do you do with 48" of battery cables when batteries are right next to each other? You have to curl them up even though it looks silly. Getting all of those cables to fit with the batteries in the battery compartment was a challenge! What about the main positive and negative cables in that situation? Let's say that you connect the main negative cable from that bank from battery 1 and the main positive from battery 4 (or vice versa). They do not need to be the same lengths. For convenience, you could also use strategically placed positive and negative bus bars. You would have a positive cable from battery 4 going to the positive bus bar and a negative cable from battery 1 going to the negative bus bar so that you don't need to have the various positive and negative appliance cables going the 1st and 4th batteries.
Mark Robbins
Tuesday 4th of July 2023
Do you need to use a trickle charger if you keep your RV plugged in all the time?
Jay
Monday 30th of June 2025
@Mark Robbins, Yes and no. If the RV is plugged in, then the built-in charger should be keeping the coach batteries fully charged. If you have a motorhome, you have separate engine batteries that are not usually charged except by the alternator, when the engine is running. Therefore, you should use a trickle charger for the engine batteries unless you absolutely know that they're being charged.