Understanding Solar Battery Voltage: 12V vs. 24V vs. 48V Systems - Which One is Right for You?

Nov 25

Choosing the right voltage for your solar battery setup can make a huge difference in your system's overall performance and cost. Basically, you have three main choices—12 volts, 24 volts, or 48 volts. So, which one is right for your power requirements and the needs of your solar power system?

If you're new to solar, this question can seem a bit confusing and maybe even a little overwhelming. But don’t worry, we’re here to help! This straightforward guide will break down the main voltage options, helping you understand the best choice for your needs, while also helping you avoid frustrating and costly mistakes early on in your solar journey.

So, let’s dive into the details of what each voltage actually means, what they’re useful for, their pros and cons, and how you can choose the right option for your specific setup.

Understanding the Basics: Voltage, Amperage, and Wattage

Before diving into what each battery voltage means, let’s make things easier by quickly reviewing three of the key terms used when discussing solar power: volts, amps, and watts.

We covered solar basics and terminology previously, but for the purposes of this quick refresher, we’re going to use a simple analogy.

Imagine you’re filling a bucket with a garden hose:

The Voltage (Volts) would be the pressure pushing the water through the hose. While the Amperage (Amps) would be the thickness of the hose itself—thicker hoses allow more water to flow. Finally, Wattage (Watts) would be the total amount of water collected in the bucket.

While these terms can seem a little bit confusing at first, the basics are actually pretty simple when you imagine electricity acting like water being collected in a bucket.

Another key equation that is important when you’re dealing with solar power systems is how Watts are calculated:

Volts x Amps = Watts

So, lowering the voltage while keeping wattage the same requires thicker wires (higher amps). In real life, this means that with lower-voltage systems that have higher wattages, you’ll need thicker, more expensive cables to handle the current.

If you’re still feeling a little bit confused, don’t worry, that’s perfectly normal. You can circle back and watch our LEARN Video Series where we provide a beginner-friendly Introduction to Solar.

If you’re still with us, it’s time to dive into a quick overview of the three main solar battery voltages, starting with 12V systems.

12 Volt Systems: Ideal for Small Solar Setups

12V batteries tend to be the most common option for small, low-wattage applications. Most people associate this lower voltage with car batteries, as well as the type of batteries used for some RV and camper van applications. For solar power systems, they’re typically used for small systems that are designed to power small-scale devices and appliances.

Here’s a quick breakdown of where these batteries are typically used, as well as some of the advantages and disadvantages of using them:

Common Uses for 12V Systems: Powering low-wattage items, like LED lights, small fans, phone chargers, or other handheld devices that have low power demands.

Pros: 12V systems are relatively affordable and work with thinner gauge cables if you have a low wattage setup.
Cons: For anything requiring more power, basically anything over 1,500 watts, like a coffee maker or a refrigerator, a 12V system would require thicker gauge and more expensive cables to handle the current safely.

For a small, lightweight setup with very limited power demands—like a few panels and a battery for a RV, small camper trailer, or very, very basic off-grid setup—12V setups can work well.

However, the power restrictions and wiring requirements can be really limiting, so for anything more substantial, you may want to go up to the next voltage level, which brings us to 24V systems.

24 Volt Systems: The Middle Ground

The mainstream adoption of 24V systems originated out of the US Military’s need for more power than 12V batteries could reliably supply to their radios and other electronics when they were fighting in remote areas during the Korean War. In the world of solar, 24V batteries are typically just used for medium-sized systems where a 12V setup wouldn’t quite cut it.

Here’s a quick overview of popular uses and the pros and cons of these setups:

Common Uses for 24V Systems: Powering basic electronics and appliances, like a coffee machine or mini-fridge. In many cases, 24V batteries can be used for medium-sized RV setups, small off-grid cabins, or basic backyard solar panel setups.

Pros: More efficient than 12V for medium power needs and requires less wiring bulk than a 12V setup at equivalent wattage.

Cons: Fairly limited scalability and slightly awkward for larger applications. They can handle around 3,000 watts effectively, but may struggle beyond that. Most solar power systems would be better off jumping up to 48V batteries, rather than being limited by 24V batteries.

If you’re building an off-grid system that requires a little more power than you can achieve with 12V batteries, but not an overly huge output, a 24V system could fit the bill.

However, if you’re serious about expanding your system in the future, or you plan on running high-wattage appliances, you might want to consider just jumping directly to a 48V setup. Basically, 24V setups can work, but they’re somewhat restricting, so why not just go all the way and go right to a 48 Volt System?

48 Volt Systems: The Ideal Solar Powerhouse

For anyone considering a substantial solar setup, a 48V system is generally the way to go. It’s the current standard for medium to large solar power systems due to its versatility, efficiency, and scalability.

Again, here are some common uses, as well as the benefits and drawbacks:

Common Uses for 48V Systems: Larger RVs, residential homes, commercial setups, or fully off-grid residential solar systems with high power demands. While 48V batteries are the go-to option for those with larger power needs, they’re also popular with smaller setups, as they can be upgraded in the future without the same limitations.

Pros: Allows for smaller gauge wires at higher wattages, reducing wiring costs and making installations tidier. They also handle larger loads with ease and they can support inverters with 3,000W up to 18,000W ratings.
Cons: Slightly higher upfront costs, but often worth the investment given the system’s power output, efficiency, and potential for expandability.

Put simply, why limit what you can do in the future by going with a lower voltage, especially given that you don’t really save that much money on the upfront cost of the batteries? Unless you know for a fact that you only need a small setup, say to power a few LED lights around your backyard swimming pool, you should just give yourself the option to expand your system in the future.

Most batteries that are suitable for solar applications, like EG4’s LifePower4 Batteries, are available in 12V, 24V, and 48V versions, yet their internal build remains pretty much the same across each model, so they the smaller voltage batteries aren’t any easier to use or anything like that.

By choosing the 48 Volt version, you can power everything from a small fridge to heavy-duty appliances with fewer wires, making the setup cleaner and more cost-effective in the long run.

For example, EG4’s 48V PowerPro Wall Mount Battery, with its 14.3kWh capacity, is one of the many efficient, all-in-one options out there that can be used for medium-sized systems, but still allows you to upgrade to a larger system in the future by adding more solar panels to your array.

Why We Recommend 48 Volts

In most cases, a 48V system is going to be a more streamlined, cost-efficient option than either a 12V or 24V system, even for smaller setups. From our perspective, the wiring requirements alone make 48V a clear winner, as you’ll need less of the thick, inflexible wiring due to the higher voltage, leading to reduced installation costs and just a much cleaner setup. Plus, 48V systems can power a broader range of devices without hitting their limits nearly as fast, so you have a lot more flexibility in what you use your batteries for.

Which System is Right for You?

While we recommend just going the 48V route, each person’s needs are going to be a little bit different, so here’s a quick overview:

12V System: Perfect for very lightweight, low-power setups with minimal wattage requirements, like a portable solar setup for camping, small RVs, or really basic off-grid uses, like charging phones during a blackout.

24V System: Better suited for medium-sized setups, though a bit of a gray area since it doesn’t scale nearly as well as a 48V setup. Basically, they can be appropriate for some requirements, but they kind of suffer from just being the middle ground. Chances are you either need a very tiny setup or one that can supply some meaningful power, so why would you limit your potential to scale up your system by going with the middle-ground batteries?
48V System: Best for any system that has higher power requirements, whether that’s a large RV, a remote cabin, or a full off-grid setup for a home.

Our Final Words

While it can seem more intimidating than it needs to be, we can’t deny that choosing the right voltage for your solar system is going to help you get the most out of your investment.

And, if you’re ready to make a decision, or you’re still feeling a little bit confused about what you need, reputable retailers, like Shop Solar and Signature Solar, can help you make an informed choice. Whether you're building a new system or upgrading an old one, it’s always a good idea to ask the experts if you’re unsure about your needs.

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