When assembling an electrical system for your camper van, you will have the option to build either a 12V or a 24V system. But how do you know which voltage to choose?
If you have been reading online forums or have friends with campers, you might be receiving a lot of different advice about which system is best. We have certainly come across these different forums and read the advice of others, but have found that the information is often incomplete and/or inaccurate.
In this post, we discuss the major differences between 12V and 24V systems, especially as they pertain to camper vans, trailers, and RVs. We will go over the pros and cons of each system and, in the end, give our recommendation as to which voltage is best for you.
If you’re ready, let’s get to it.
What Is A Volt? A (Very) Basic Introduction
In simplified terms, voltage is the pressure that pushes electrical current (amps) through electrical wires. If you can think of water flowing through a pipe, voltage is the water pressure that is pushing water through the pipe. The higher the voltage, the faster the water is being pushed.
When comparing 12V and 24V systems, electrical current in a 24V system is being pushed twice as fast than in a 12V system. Does this make 24V better than 12V power? Not necessarily. A more nuanced answer depends on the specifications of your electrical system.
When we talk about 12V and 24V electrical systems, what we really mean is what the ‘operating voltage’ is of the battery bank. Based on the individual battery specs and/or how multiple batteries are wired together, the total battery bank can emit power at either 12V or 24V.
You just need to decide which voltage you want your battery bank to operate at.
12V System For Camper Vans (Pros & Cons)
The vast majority of camper vans utilize 12V electrical systems. This is because this system is generally simpler to build. However, there are important drawbacks that you should be aware of. Below, we cover the pros and cons of 12V systems, especially as they pertain to camper vans, trailers, and RVs.
Benefits Of 12V Systems
Simplicity and ease of installation is the primary benefit for installing a 12V electrical system. Let’s look at the four ways choosing 12V makes for an easier installation process.
1. More 12V Device Selection
Do a simple DC-power product search on Amazon (e.g. LED DC lights) and you will notice immediately that there is a much larger selection of 12V products than 24V products. This will be true for every DC electrical device (water pumps, fridges, diesel heaters, etc). The popular Maxxair and FantasticFan vent fans do not even sell 24V models.
2. No Need For A Voltage Converter
24V systems can still use 12V devices, but you will need to install a voltage converter to step-down the voltage from 24V to 12V. This is a relatively simple solution, but does require additional costs and installation steps.
If using a voltage converter, we recommend the Victron Orion converter. This powerful unit handles up to 70A of power and is installed in-line just before the 12V distribution panel.
Great for people with 24V systems who want to use 12V devices. Install in-line before the 12V fuse panel.
3. Fewer Voltages To Take Into Account In The System
Another reason why 12V systems are simpler is because you will likely only have to deal with two voltages in your electrical system; 12V DC and 110V AC. The 12V batteries feed the 12V devices, and the batteries can also be connected to an inverter to power 110V appliances.
24V systems have to deal with more voltages and voltage conversions, which we cover in the 24V section further below in this article.
Drawbacks Of 12V Systems
There are several cons of 12V systems that you should know before moving forward.
1. Thicker Battery & Inverter Wires
Since there is less voltage in a 12V system (compared to 24V), the amount of current (amps) is increased (assuming wattage is consistent).
This is because watts = volts x amps.
As volts go down, amps must go up if wattage is to be equal.
Since amps (electrical current) is the ultimate factor in wire size, a 24V system is able to use thinner electrical wires than a 12V system. The immediate consequence is that the cost to purchase electrical wire for a 12V system is often more than for a 24V system because thicker wires contain more copper metal and, thus, are more expensive.
2. Max Inverter Rating Of 3000W
For most general consumers, 4/0 AWG wire gauge is the thickest wire you will be able to buy. It is for this reason that the largest inverter you will be able to use with 4/0 wires, in a 12V system, is a 3000W inverter.
If you are looking to use a larger inverter, like 5000W, you will almost certainly need to switch to a 24V system.
3. Larger Solar Charge Controller
Because the flow of amps through a 12V system is higher than in a 24V system, you will need a larger solar charge controller, if you plan to install solar panels. A larger charge controller will also cost you more money.
Download our FREE PDF to help build your van's electrical system; from batteries, to solar, to inverter, and more. 38+ pages of detailed diagrams, product recommendations, and links to additional resources.
24V System For Camper Vans (Pros & Cons)
For some, 24V battery systems offer very real advantages. In this section, we review the pros and cons of 24V systems as they specifically pertain to camper vans, trailers, and RVs.
Benefits Of 24V Systems
Below are three clear advantages of a 24V system.
1. Thinner Electrical Wires
As previously mentioned, fewer amps flow through the electrical wires in a 24V system than in a 12V system. This means you can use thinner gauge wires throughout your electrical system. And in general, the thinner the wire, the cheaper they cost.
How much can you save by using thinner wire? The shorter the wire, the less money you would be saving by getting a smaller wire. So real savings is only achieved if you are making extremely long wire runs (20’+) throughout the camper.
2. Smaller Solar Charge Controller
Fewer amps flowing through an electrical system also means you can purchase a smaller solar charge controller, if you will be installing solar panels on your camper van. In general, the smaller the charge controller, the cheaper the cost.
How much money can you save by using a smaller solar charge controller? The amount of savings by using a smaller charge controller depends on the total wattage size of the solar array. If you only have a 200W solar array, your charge controller savings by switching to a 24V system is smaller than if you have a 1400W solar array.
3. Larger Max Inverter
Due to the limitation of conventional wire sizes (up to 4/0 AWG), the largest inverter you could use in a 12V system would be 3000W. If you were to switch to a 24V system, however, you can use up to a 5000W-rated inverter. This may be important if you want to run an air-conditioner and other high-powered AC devices simultaneously from your batteries.
Drawbacks Of 24V Systems
The only real drawback of a 24V system is that they are generally more complex to build. This is because you will need to factor in a greater number of operating voltages and voltage conversions than in a 12V system. This includes:
- 24V batteries
- 12V devices
- 110V devices
Additionally, there are significantly fewer options for standalone 24V batteries. This means you will likely need to build a 24V battery bank from two 12V batteries or four 6V batteries (wired in series), which is an additional voltage conversion and installation complexity.
Are 24V Systems Cheaper?
One of the most popular arguments in favor of 24V systems is that they cost less than 12V systems. This is mostly due to the fact that 24V systems use thinner gauge wires and smaller solar charge controllers.
But is a 24V system guaranteed to be cheaper? Not always.
Below we put together a table comparing the different wiring components needed to build a 12V and 24V system for a camper electric system. This comparison assumes a 400W solar array and a 2000W inverter/charger.
For simplicity, we eliminate all components that are used in both systems and only focus on the differences.
In the above table, we show that in some circumstances, a 24V system can actually cost you more money. This is because even though you might save money with thinner wires and a smaller solar charge controller, the savings is offset with having to buy a voltage converter to step down the 24V to power the 12V devices.
But if you are building a system for a much larger camper (RV or trailer), the differences in cost may be more substantial. You will need to do your own item-by-item product comparison for your own unique build.
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Our Opinion: Is A 24V System Better?
By now, you should have a strong understanding on the important differences between 12V and 24V electrical systems, especially as they pertain to camper vans and mobile living. So then which of the two do we prefer?
In our opinion, the advantages of a 24V system are only truly realized if you plan to:
- Build a solar system larger than 700W: Saves money with smaller charge controller and wire costs
- Convert a large RV or trailer: Saves money on wiring costs for long wire runs
- Require an inverter larger than 3000W: 3000W max for 12V systems due to 4/0 AWG max wire size
If you are converting a small to medium sized camper van with a modest electrical system, we do not see the benefit of building a 24V system since you likely would not be using enough electrical wire or a large enough solar charge controller to see any meaningful cost savings. In fact, you may even end up spending more money if you buy a voltage converter to power your 12V devices.
Review our 12V vs 24V comparison chart below for a summary.
12V | 24V |
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We use a 12V system in our camper van and it has absolutely served us well over the last 4+ years.
Enjoyed reading? Check out our “DIY Camper Electrical System” category page for more similar content.
Conclusion
We hope you learned about the major differences between having a 12V and a 24V electrical system in your camper van conversion. While there are a number of different factors to consider, we still believe that if you are building a modest-sized camper van, then a 12V is best for you. If you are planning to build a much larger electrical system, consider going with 24V.
If you have any questions, please let us know in the comments section below.
Happy building!
Go Back: DIY Camper Van Conversion Guide
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