My quick off-the-cuff response as I’ve worked with several RV’s:
Unless you’re installing a huge battery bank with 800+ amp hours, stick with a 12-volt configuration.
The majority of RVs are equipped with 12-volt DC (battery-powered) and 120-volt AC (household power) devices. If you change your battery voltage you will either need to change all your 12-volt devices to the proper voltage (24-volt devices exist) or add an extra component, a DC-to-DC converter, AKA Buck Converter, AKA Step-Down converter, to bring your battery voltage back down to 12-volts.
So if you’re working with 6-volt batteries, wire those into a 12-volt series or series-parallel configuration, and if they are 12-volt batteries keep them in a parallel configuration. Learn more: How to Wire RV Batteries
Series vs Parallel: Basics
Wiring in series increases the voltage while keeping the amp-hour capacity the same. This means two 6V batteries can become a single 12V power source when connected in series.
Parallel wiring keeps the voltage the same but increases the capacity. So, wiring two 12V batteries in parallel means you’ll get more amp-hours but still output 12V.
You can have both series and parallel wiring when you use 4, 6, or more 6-volt batteries. Two 6-volt batteries get wired in series for 12-volts, and then those two batteries get connected to another 2 with a parallel connection. This keeps the entire bank at 12 volts.
Both setups have distinct uses depending on your power needs.
Voltage and Amp-Hours
Voltage refers to the electrical potential of the battery. For most RV applications, you need a consistent 12V supply.
Amp-hours indicate how much power the battery can deliver over time.
If a battery has 100 amp-hours, it means it can deliver 1 amp for 100 hours or 10 amps for 10 hours. Balancing voltage and amp hours ensures your setup meets your energy demands.
When TO Use Higher Voltage
For most RV owners, a 12-volt system is sufficient and straightforward. However, there are situations where using a higher voltage system might be beneficial:
Large Battery Banks
If you’re planning to install a large battery bank, say 800 amp hours or more, a higher voltage system can be more efficient. Large battery banks at 12 volts require very thick and expensive wiring to handle the high current. By increasing the voltage, you can reduce the current, allowing you to use thinner, more manageable, and less expensive wires.
High-Power Appliances
If you have high-power appliances or plan to run multiple devices simultaneously, a higher voltage system can provide more stable power. This is particularly useful for off-grid setups where power demands are high.
Long Cable Runs
In setups where the distance between the batteries and the devices they power is significant, higher voltage systems can reduce power loss. Higher voltage means lower current for the same power output, which minimizes voltage drop over long cable runs.
Advanced Solar Systems
For those with advanced solar setups, higher voltage systems can be more efficient. Many high-capacity solar panels and inverters are designed to work with higher-voltage systems. This can make your solar setup more efficient and easier to manage.
Final Thought on Wiring Your Battery
If you’re not planning a massive solar and battery system just stick with the basics and make really good connections. You can find how to wire different battery setups on my How to Wire RV Batteries page. If you are planning a large battery and solar system you should do a full comparison of the efficiency and cost associated with going with a higher voltage system.