What’s best for a bus build – 12V, 24V, or 48V solar system? Each have their pros and cons, and choosing the right one isn’t a matter of preference. It’s a technical question with an objective answer, yet not without first accounting for a variety of factors such as bus size and usage, to name a few.

Let’s break it all down so you can make the smartest choice for your build.

What’s the Difference Between 12V, 24V, and 48V?

In simple terms, the number refers to the system’s voltage. The higher the voltage, the more power your bus can handle at a given time. It’s nice to be able to run your air conditioner, coffeemaker, and instant pot all at once without worrying about flipping a breaker.

While being able to push more power is a plus, there are costs to having more power than you need or what your bus can handle. A 48v system is impractical for a bus that can only store 1800w of solar power, for example. 

More volts can mean more efficiency, but only when everything else in the system is designed to benefit from that increase. In a holistic bus build—especially when factoring in things like cost, repairability, and compatibility—jumping to 48V often introduces more problems than it solves.

Why You Shouldn’t Use 48V

It’s easy to be lured by the promise of efficiency and cost-savings with 48V systems, but when you actually break it down, 48V is rarely ideal for bus conversions.

People are drawn to 48V systems for off-grid bus conversions because, on paper, they offer a few appealing technical advantages—especially for larger and more power-hungry setups. Here’s why 48V can seem like the smart choice (and in some rare cases, it actually is):

⚡ Efficiency Over Long Distances

Higher voltage = lower current for the same power output. Lower current means thinner wires and less energy lost as heat. For long cable runs (like from solar panels on a roof to batteries inside), this can seem like a win.

But the reality is that 12v and 24v cables are more than capable of handling the distance between the roof of your bus and your batteries. Even if you want to set up a solar array 50ft from your bus while parked for a season, 12v and 24v cables will give you nothing to worry about. 

🔋 Larger Inverter & Solar Compatibility

48V systems can handle bigger inverters and larger solar arrays. A 5,000W+ inverter runs more efficiently on 48V than 12V or 24V. This is ideal for setups running air conditioning, induction cooktops, or other high-draw appliances.

But unless you’re operating a welding facility out of your bus, this is overkill.

🔌 Single Conversion Path

48V DC to 120V/240V AC is a direct step, often simplifying system design. You don’t need to worry as much about running 12V DC appliances if you plan to run nearly everything off AC.

This is the only upside to 48V.

More Costly Than You Think

48V systems require specialized components that aren’t as readily available as their 12V and 24V counterparts. You can get 12v and 24v fuses and parts at any auto parts store. If an inverter fails, you can find 12v and 24v at a truck stop to get you by. This isn’t the case for 48v.

While 48V might sound like a modern, pro-level option, it’s actually an overbuilt system for most buses, especially under 30 feet.

The only time 48V really makes sense is if you’re running a sizable solar array (using more panels than you can fit on your bus roof) and need a high-wattage inverter (5,000W or more). And that’s typically for off-grid cabins or terribly inefficient, power-guzzling RVs—not buses.

Pros and Cons of 12V

12V is great for smaller buses, like shuttle buses or shorties under 30 feet. It keeps everything simple, compatible, and easy to maintain—especially if you’re not pushing 2000W of solar or running huge loads.

I’ve powered over 200 buses and have a 25’ Shuttle Bus. Years ago I did a 24hr system on it with a 2400w Inverter. This size bus shouldn’t need more than that and this size bus cannot hold more than 1800w or so of solar…if I did it again, I’d do 12v though at the time it was a bit less expensive to do 24v. Since then, Victron prices dropped and the way we do batteries have changed so the savings now is pretty trivial for that size system I had used.

Cons:

• Less efficient over long cable runs (higher current = thicker wire)
  

• Not ideal for high-power inverters or large solar setups

• Can lead to more bulk and wiring complexity in larger builds 

Pros and Cons of 24V

Once you’re in the 30’+ bus range, you have the space for 2000w+ of solar, and you start flirting with the need for larger Inverters in many cases. This is where 24v starts to make technical sense. Most buses I do are this size up to 40’ and they all get 24v Systems. With this, you get the best of both worlds with the only negative being the need for a 24-12v converter, which leaves your system with a single point failure for 12v items. With a 12v system, this isn’t the case. But there are solutions for this and it’s still worth going 24v.

24V hits the sweet spot for most bus builds in the 30–40 foot range. While it introduces the need for a converter, the efficiency gains and cleaner wiring layout are worth it. Most buses I’ve powered in this size range use 24V and perform exceptionally well.

Cons:

• Requires a 24-12V converter for common 12V items (lights, fans, etc.)
  

• That converter becomes a single point of failure for your 12V items

How to Determine If Your Bus Should Be 12V or 24V

So, what’s right for your bus? Loosely speaking, buses under 30 feet could do better with 12V, while buses over 30 feet could do better with 24V. While this is a good rule of thumb to start, it’s not a catchall and you could be overlooking some serious factors if you took this as a rule of law.

Determining 12V vs 24V isn’t a decision that can be made independent from your inverter size, battery storage, the number of solar panels you can fit on your roof, the amount of power you’ll be pulling and in which season… the list goes on. 

If you’re really looking to build the best long-term solution for your bus, book a consult with me. I’m regularly saving thousands for my clients, often from a single phone call.

You’ll save the most by booking a consult before you even start on your insulation. Do it right with a clear plan and you’ll avoid the disasters that take the fun out of the bus life.

I’m constantly having to fix solar installations made by people other than me who didn’t take all the data into consideration. It can take a lot more time and money to fix these issues. I would much prefer to help you now than after such an experience. 

Book a call here.