12V vs 24V: Which is Best for Your Battery System

When setting up solar power systems or off-grid energy solutions, the 12V vs 24V debate is a common dilemma. Whether outfitting a home, RV, boat, or backup system, the decision often hinges on understanding the nuances between these two voltage options.

Whether you're upgrading your power storage or designing a new setup from scratch, understanding the differences between 12V and 24V can help you make an informed decision. In this article, we will explore key comparisons between the two voltages, including performance, efficiency, and practical applications.

Basics of 12V vs 24V battery

When discussing 12V vs 24V systems, we're referring to the nominal voltage—the average voltage provided by a battery system under normal operating conditions.

For example, typically, LiFePO4 battery banks are made up of 3.2V battery cells, with a voltage range from 2.5V to 3.65V.

A 12V system consists of 6 cells, which will have a voltage range of 11.5V to 12.8V.

A 24V system consists of 12 cells, with a voltage range from 23V to 25.6V. A voltage chart can help visualize the voltage levels for different battery configurations.

Additionally, you can make a 24V system with 12V batteris by series connections. By linking the positive terminal of one 12V battery to the negative terminal of another, you effectively double the voltage while keeping the overall capacity the same.

However, this flexibility can sometimes lead to confusion when choosing between 12V vs 24V.

12v vs 24v, what's the difference

Which is more compatible with different electrical systems

12V systems are the most common choice for cars, RVs, boats, and small off-grid setups. One of the main reasons for this is the sheer availability of 12V loads on the market. Many household appliances, tools, and electronics are designed to run on 12V, making it easier to find compatible devices. From lights and fans to refrigerators and television sets, you’ll find a wider variety of off-the-shelf 12V devices compared to their 24V counterparts.

While less common, 24V systems are often used in larger setups, like large RVs, semi truck, and marine industry. They are particularly useful in systems where higher power demand is required, or where wiring needs to span a greater distance without excessive voltage drop. However, the market for 24V devices is more specialized, and you may find fewer options compared to 12V devices.

Which storage more power

The choice between 12V and 24V also affects the decision regarding the battery's Ah capacity. When comparing energy storage, the key factor is the voltage and amp-hour (Ah) rating. The energy capacity of a battery is measured in watt-hours (Wh), which is calculated as Voltage x Amp-hours.

For example, a 24V 100Ah battery stores 2.4 kWh of energy, while a 12V 100Ah battery stores 1.2 kWh, which is half of what a 24V setup would store. To achieve the same energy storage as a 24V 100Ah battery, you would need an additional 12V 100Ah battery. You have two options:

• Connect two 12V 100Ah batteries in series to create a 24V 100Ah system, storing 2.4 kWh of energy, matching the 24V 100Ah battery's capacity.
• Connect two 12V 100Ah batteries in parallel to create a 12V 200Ah system, storing 2.4 kWh, the same amount of energy as the 24V 100Ah battery.

Feel free to read our related article on battery connections to explore the differences, or check our guide for converting 12V batteries to 24V.

Which makes more power

Power output depends on the battery's voltage and the load connected to it. According to the power formula Power = Voltage × Current, for the same load (i.e., the same current), a higher voltage will result in more power output.

For example, using a 40A charge controller, we can see the difference clearly. For a 12V system, the power output is 480W (12V × 40A), while for a 24V system, it’s 960W (24V × 40A). This means the 24V system produces twice the power of the 12V system with the same current.

Which is more efficient

In realistic terms, power is what actually drives your devices, and both systems can meet the same power requirement by supplying the right combination of voltage and current.

For instance, to power a 1000W device, a 12V system needs about 84 amps, while a 24V system only requires 42 amps. And the amp flow determines the wire size, and since a 24V system uses lower current, it needs smaller, less expensive wiring, reducing costs and minimizing energy losses. A 12V system, with higher current, requires larger, more costly wires, leading to higher costs and less efficiency.

In summary, a 24V system delivers power more efficiently, making it the better choice for high-demand or extended-use applications.

Which is more space-saving

A 12V system might need more batteries to provide the same amount of energy (kWh) as a 24V system with the same amp-hour (Ah) capacity.

Plus, 12V systems typically need more current to produce the same power, which means you'll need thicker wires, and the setup could take up more space due to the extra connection. Overall, it might be bulkier, especially if you're using multiple batteries.

A 24V system requires less current to deliver the same power, which means you can use smaller wires. This can save you space and reduce costs on the wiring while improving system efficiency.

If space is a premium in your setup, a 24V system might be a better choice, especially for large setups or systems that require long wiring runs.

Which is easier to install

12v battery is easier to install for smaller setups, with straightforward wiring. However, if upgrading to 24V, you’ll need to create series connections by linking two 12V batteries, adding complexity.

Installing a 24V battery system simplifies the system by reducing the number of connections and minimizing energy loss. However, if you're recharging from a 12V alternator—common in smaller vehicles or older systems—you'll need a 24V to 12V DC-DC converter to step up the voltage. This adds installation complexity and can introduce energy losses, which depend on the quality of the converter.

As for comparing energy loss from a DC-DC converter versus series 12V battery wiring, there isn't a clear answer, as both the converter's efficiency and cable length affect the total loss. A high-quality converter typically operates at around 95% efficiency, but this can vary, while longer cables can increase loss due to resistance. Both factors depend on your system setup.

Pros and Cons of 12V vs 24V Battery Systems

To help you better understand the advantages and disadvantages of 12V and 24V systems, here’s a comparison table based on key factors discussed above:

Factor	12V System	24V System
Compatibility	Widely compatible with 12V devices.	Fewer 24V device options.
Battery kWh capacity (for the same Ah capacity)	Less power storage.	More power storage.
Power output (at the same amp current)	Provides lower power for the same current (e.g., 120W at 10A).	Delivers twice the power for the same current (e.g., 240W at 10A).
Efficiency (for same power output)	Less efficient due to higher current and larger wires.	Lower current and smaller wires make it more efficient.
Space-saving	Takes up more space for multiple battery systems.	More compact, saving space.
Installation complexity	Easier to install for smaller setups but requires series connections for 24V.	Straightforward installation for single 24V battery but may need a DC converter for 12V output.
Cost	Generally less expensive for smaller setups, widely available.	May be more expensive for higher-capacity batteries but more cost-effective for larger systems.
System scaling	Requires additional batteries or series connections for higher voltage.	Easier to scale, especially for larger systems, with fewer components.

Conclusion: 12v vs 24v, which is right for you

In summary, the key factors affecting your choice between 12V vs 24V systems are compatibility with the devices you plan to run, the total wattage of those devices, and future scalability.

Since load power determines the current required a electrical, this affects wiring size, energy loss, and overall efficiency.

To make the best decision for your needs, it’s wise to first plan the appliances you need to power and then select the battery voltage that fits your performance requirements.

General Guidelines:

• If you're running devices with a total load of below 3000W, a 12V system is usually sufficient.
• For systems needing 3000W to 4000W, a 24V system is recommended for better efficiency and reduced wiring costs.

If you’re using a 12V system but need to power higher-demand devices, you can upgrade to a 24V system by connecting additional 12V batteries in series. You may also require a DC-DC converter to match the system voltage with your charging source, such as a 12V alternator or solar panel. Upgrading to 24V can improve scalability, reduce current flow, and boost power efficiency, especially for larger systems. Additionally, having separate 12V and 24V solar systems can simplify setup and reduce complexity.