When assembling an electrical system for your camper van, you can build 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 receive different advice about which voltage system is best. We have come across these various forums ourselves and read the advice of others but have found that the information is often incomplete and inaccurate.
This post discusses the significant differences between 12V vs. 24V systems, especially regarding camper vans, trailers, and RVs. We will go over the pros and cons of each method 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 pressure pushing water through the pipe. The higher the pressure, the faster the water is being pushed. Therefore, the higher the voltage, the quicker the electrical current travels through the wire.
Which Voltage Is Best For Your Camper Van?
When comparing 12V and 24V systems, the electrical current in a 24V system is being pushed twice as fast as 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, we mean the ‘operating voltage’ of the battery bank. Based on the individual battery specs and how multiple batteries are wired together, the total battery bank can emit power at either 12V or 24V.
You must decide which voltage you want your battery bank to operate at.
Pros & Cons of 12V System For Camper Vans
The vast majority of camper vans utilize 12V electrical systems. This is because this system is generally more straightforward 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.
Pros Of 12V Systems
Simplicity and ease of installation are the primary benefits of installing a 12V electrical system. Let’s look at the four ways choosing 12V makes for a more straightforward installation process.
1. More 12V Device Selection
Do a simple DC-power product search on Amazon (e.g., LED DC lights), and you’ll immediately notice a much more extensive selection of 12V products than 24V ones. 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 must install a voltage converter to decrease 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 before the 12V distribution 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 further in the 24V section below in this article.
Cons 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 vs. 24V system, the 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 can use thinner electrical wires than a 12V system since there are fewer amps. 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, a 4/0 AWG wire gauge is the thickest wire you can buy. For this reason, the largest inverter you can use with 4/0 wires in a 12V system is a 3000W inverter.
If you want 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 install solar panels. A larger charge controller will also cost you more money.
Example: A 400W solar array requires a Victron 100/30 charge controller when hooked to a 12V system. But the same solar array only needs a Victron 75/15 controller in a 24V system, which is ~$60 cheaper.
Pros & Cons of 24V System For Camper Vans
For some, 24V battery systems offer genuine advantages. This section reviews the pros and cons of 24V systems, specifically camper vans, trailers, and RVs.
Pros Of 24V Systems
1. Thinner Electrical Wires
As mentioned earlier, 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, which are generally cheaper to purchase.
How much can you save by using thinner wire? The shorter the wire run, the less money you would save by getting a smaller wire. So, savings are only achieved if you make long wire runs (20+ feet) throughout the camper.
Example: If using the Victron 2000W inverter/charger, Victron recommends 2/0AWG wire (70mm²) for a 12V system but only 2AWG wire (35mm²) for a 24V system.
2. Smaller Solar Charge Controller
Fewer amps flowing through an electrical system also means you can purchase a smaller solar charge controller if you install 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 savings achieved 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. However, if you switch to a 24V system, 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.
Cons Of 24V Systems
The only real drawback of a 24V system is that they are generally more complex to build. You must factor in more operating voltages and voltage conversions than in a 12V system. This includes:
- 24V battery bank
- 12V devices
- 110V devices
Additionally, there are significantly fewer options for standalone 24V batteries. You will likely need to build a 24V battery bank from two 12V batteries or four 6V batteries (wired in series), an additional voltage conversion, and installation complexity.
Are 24V Systems Cheaper?
One of the most popular arguments favoring 24V systems is that they cost less than 12V. This is mainly because 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 used in both systems and only focus on the differences.
The above table shows that in some circumstances, a 24V system can cost you more money. This is because even though you might save money with thinner wires and a smaller solar charge controller, the savings are offset by buying 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 item-by-item product comparison for your unique build.
Our Opinion: Is A 24V System Better?
By now, you should understand the essential differences between 12V vs. 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 genuinely 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
Suppose you convert a small to medium-sized camper van with a modest electrical system. In that case, 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. You may even spend more money if you buy a voltage converter to power your 12V devices.
Review our 12V vs 24V comparison chart below for a summary.
We use a 12V system in our camper van, which has served us well over the last 4+ years.
We hope you learned the significant differences between 12V vs. 24V electrical systems in your camper van conversion. While there are several 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 plan to build a much larger electrical system, consider using 24V.
Please let us know in the comments section below if you have any questions.
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