12 Volt vs. 24 Volt RV Solar
You may have noticed that solar panels come in both 12V and 24V. If your existing electrical system is 12V, like in an RV, which already wired and equipped with 12V appliances, then you should stick with a 12V solar system.
Another thing to consider, the batteries typically available for use on a recreational vehicle are either 6V or 12V. It’s common for motorhomes to have two 6V batteries wired together to create a 12V system.
Solar systems that are 24V are for large-sized solar installs, such as 1Kw-5Kw. Recreational vehicles generally have small solar systems, generally from 175 watts to 750 watts. Thus, 24V panels and solar equipment may be more appropriate for a home solar system.
Advantages of the 24 Volt
The advantage of using a 24V battery bank is that it can save you money since you need less in the way of charge controllers and you can use smaller gauge wires for the same amount of energy. However, the amount of money you might save on wiring an RV would be nominal.
Another advantage of 24V is that it is more compatible with AC appliances. However, most RVs are already equipped with 12V appliances. But you could bring down the voltage from 24V to 12V using a charge controller.
Advantages of the 12 Volt
Using a 12V solar system is recommended when you need to run your appliances directly from batteries. Overall, 12V is safer for DC circuits as opposed to 24V. Most RV appliances operate on 12 volt systems making this the most compatible, and therefore, making 24 volt systems unnecessary, or even counterproductive for use on recreational vehicles. Of course, you could install a charge controller that reduces 24 volts to 12 volts.
24 Volt May Be Appropriate for Self-Built RVs
If you are planning on building out your own van, or, building your own trailer from scratch, then you might consider using a 24V solar system. Likewise, some large buses you might want to convert to use as an RV may already be wired for 24V. In this case, you can choose appliances that will work with 24 volts, or, you could use a charge controller to reduce it to 12 volts, so you could use typical RV appliances, such as an RV refrigerator and water pump.
The bottom line seems to be, there are few advantages to installing a 24V solar system in an RV over a 12V system unless you are going to install a very large solar system on your RV. While a 24V system does have some advantages over 12V, if you have to convert much of your power back down to 12V to run your appliances, it’s not logical to install a 24V solar system on an RV.