Where This Voltage Comparison Comes From

Every claim in this article comes from one source video — The Solar Lab’s Which is Best? - 12 vs 24 vs 48 Volt Solar Batteries Explained, which has been watched more than 380,000 times. The video walks through the difference between 12V, 24V and 48V battery systems, explains volts, amps and watts with a garden-hose analogy, and gives a clear recommendation for each size of solar build. If you would rather watch the explanation before reading the breakdown, the video is right here:

The Solar Lab — “Which is Best? - 12 vs 24 vs 48 Volt Solar Batteries Explained”
Watch on YouTube →
380K+ views. The Solar Lab breaks down 12V, 24V and 48V solar battery systems with a simple volts/amps/watts analogy, covering wire gauge, cost and exactly which voltage fits which size of system.

Volts, Amps and Watts: The 60-Second Lesson

Before comparing the three voltages, the video spends about a minute making sure everyone is working with the same three terms. The analogy it uses is a garden hose: the pressure waiting in the faucet is your volts, the thickness of the hose you attach is your amps, and the total amount of water that lands in the bucket is your watts. Thin hose, less water per minute; thick hose, more water. The one formula to remember is volts × amps = watts.

Apply that to wiring and the picture gets practical fast: drop the faucet pressure from 120V down to 48V and you need a much thicker hose — in real life, a much thicker gauge wire — to deliver the same number of watts to your inverter. That single relationship drives almost every trade-off in this comparison, so it is worth reading twice: at the same wattage, a lower-voltage system always needs more current, and more current means bigger, more expensive cable.

Where 12V Systems Make Sense

A 12V system is the most common thing you will find in a car, a small trailer or a compact RV, and it looks familiar because it has been around forever. The video points out that 12V batteries are generally used for low-wattage jobs: LED headlights, small fans, charging phones and devices. Because those loads are small, thin wire is fine, and a bundle of thin wires sits cleanly loomed inside an engine bay.

The trouble starts when you attach a small 12V battery to a solar setup. Solar users typically want higher wattage — a coffee maker, a fridge, lights and small appliances. The video is blunt about the ceiling: past roughly 1,500 watts, a 12V system needs thick cables carrying a lot of amps, and those cables cost real money and get bulky fast. Its verdict: a 12V system is best for a smaller application no larger than about 1,500W — a trolling motor, a small camper trailer or an extremely light off-grid setup.

24V: The Awkward Middle Step

The video credits the US Army in the Korean War for the existence of 24V vehicles, but notes that in the solar world, 24V probably started with people taking the two 12V batteries they already owned and wiring them in series so they could use smaller wire. You will often see 24V in a medium-size application — an RV, a small off-grid cabin — something that needs a bit more power than 12V but is not a huge system overall.

Here is where the video makes its strongest opinion: the jump from 12V to 24V is an awkward one, and for most builders it is worth skipping. It rates 24V as good for anything up to about 3,000W, but then says that if you are not building a tiny 12V system, you might as well go straight to 48V. The middle voltage exists, it works, but it is increasingly a solution looking for a problem in a market where 48V components are now the default.

Why 48V Is the Standard

If you are building any kind of solar kit right now, 48V is the standard — whether the system is small or quite large. The video’s reasoning is versatility: you can get a 48V inverter as small as 3,000W and as large as 18,000W, and batteries like the EG4 LL or the LifePower4 series come in 12V, 24V or 48V versions that are exactly the same cells wired differently. So the video asks the obvious question: why not jump straight to 48V?

The practical payoff is wiring. At 48V you run the same load you would run on 12V or 24V with a much smaller gauge wire, because you need far fewer amps — the higher voltage makes up for it. That means less money on cabling, a cleaner install, and the headroom to grow. The video also shows a 48V wall-mount battery, the EG4 wall mount, which is around a 14kW battery at 48V — a density you simply cannot reach with a 12V pack in the same footprint.

The Wire Gauge and Cost Trade-Off, With Numbers

The reason voltage matters so much in practice is the relationship between current and cable size. The video makes the point conceptually with the hose; a commenter on the video (see the Q&A section below) then puts real numbers on it. A 20A charge controller at 12.8V can handle up to about 256W of solar panels; that same controller at 51.2V can handle over 1,000W. At 48V, 2 AWG main battery and inverter wiring nets about 100A at 51.2V — roughly 5,000W of continuous power without the cable getting warm.

Those numbers explain the cost argument. Thick copper is the expensive part of any low-voltage install, and the thicker the cable, the more it costs and the harder it is to route. Because a 48V system moves the same power with a quarter of the current, the cable bill drops sharply — which is why the video says you spend a lot less on wiring and can run a bigger, beefier system more cleanly. The trade-offs are real but narrow: 48V components need a bit more electrical skill, fusing and breakers matter more, and solar-string topology needs more attention — the details a good charge controller selection guide covers.

12V vs 24V vs 48V: Quick Parameter Comparison

The table below compiles the video’s guidance into one view. Wattage ranges and wiring advice follow The Solar Lab’s recommendations; the controller and cable math comes from the top technical comment on the video, which matches the channel’s own numbers.

Parameter 12V System 24V System 48V System
Typical max wattage (video) ~1,500W ~3,000W 3,000W – 18,000W+
Best-fit use Car, small trailer RV, trolling motor, lights and phone charging Medium RV, small off-grid cabin Any serious solar kit — the current standard
Current for 1,000W load ~78A (thick cable) ~39A (medium cable) ~19.5A (thin cable)
Same battery, different wiring Yes — identical cells Yes — identical cells Yes — identical cells (EG4 LL / LifePower4)
Video recommendation Small setups only, ≤1,500W Skip it — go straight to 48V Default for any new build

Same Cells, Different Voltage: What Actually Changes

One of the most useful points in the video is that the cells inside a 12V, 24V and 48V battery are frequently the exact same cells. A LifePower4 battery from EG4, for example, is sold in 12V, 24V and 48V versions — the difference is only how the cells are wired together. So choosing a voltage is not a quality choice; you are not getting a better or worse battery by picking 12V over 48V. You are choosing the output potential and, more importantly, the wiring economics of the whole system around it.

For a buyer, this reframes the decision. If you are replacing one 12V battery in an existing camper or boat, stay 12V — matching the system you already own. If you are building from scratch, the video’s advice is to design for 48V from day one, even if you only need a few kilowatts now, because the same pack can grow later and the wiring you install today will not need replacing when you double the system.

Common Misconceptions About Battery Voltage

The comments on the video surface two misconceptions worth clearing up. First, some viewers assume 48V is only for large systems — the video explicitly disagrees and recommends 48V even for small solar kits because of its versatility. Second, there is a persistent idea that 12V is always cheaper; in a small, truly minimal setup that can be true (a couple of 12V outlets and a small inverter), but once you size for a real load like a fridge plus lights plus a laptop, the thicker 12V cable cost quickly eats the difference, which is why the video and its top commenters steer medium builds to 48V.

There is also a fair caveat raised in the thread: if your build runs DC loads directly without an inverter, skipping 24V deserves a second thought, because some DC appliances are happy at 24V. And one commenter notes that on a 48V system almost nothing runs directly off the battery, so the inverter is in the circuit all the time — a real efficiency consideration for very small cabins where every watt counts. The balanced takeaway: 48V is the right default for most builds, but match the voltage to the loads you actually have, not to a marketing chart.

How We Apply This at Dajiu Energy

This is exactly the kind of decision we help customers make every day as a Chinese manufacturer of LiFePO4 batteries for RVs, homes, golf carts and portable applications. Our product range covers LiFePO4 drop-in replacement batteries, EV and golf cart batteries, wall-mounted home storage, portable power stations, commercial energy storage and battery swap cabinets — explore the full lineup in our product center, or browse more buying guides. Whether you need a 12V drop-in replacement for an existing RV bank or a 48V wall-mount system sized for a full home, tell us your voltage, capacity and compartment dimensions and we will engineer the pack around your real wiring plan — because the voltage choice is a system choice, and it should be made on the actual load math, not on habit.

What Viewers Are Asking (Top Comments on the Video)

These are the most useful of the video’s top comments, with our practical answers. The original creator did not reply to these threads, so the answers below are ours — written the way we’d answer a customer on the shop floor. Thanks-only comments were left out on purpose; these are the ones with actual information in them.

@M.A.D.I.ANALYTICS · 65 likes
"Ok... I want to say he does a pretty fair job explaining with his analogy. The fundamental rule of thumb for picking your voltage is the following: think as of this system is 100% off grid. If you are aiming to keep minimal 120v 15amp circuits limited to approximately x3 in full use and near full demand. Go with 12v If you are planning the same but also need 30amp devices go with 24v If you are planning on full scale 100% home use which includes 50/60amp demands. Then go 48v. The concept is this. Your inverters "work" to provide power for potential use is rated by its internal components. The wider the range of amp potential the higher the voltage that is needed. Higher voltage supply means less internal wear & tear on the PCB and its soldered connections. Think of it like this. You have unleaded gas 87oct. You have a straight 4 tractor engine = 12v You have V6 = 24v You have V8 = 48v each engine will perform work but the higher the demand the lesser engines work harder in order to provide or even stall/burn out."
Our take: This rule of thumb is genuinely useful and matches how we size customer systems. In practice we use a slightly simpler version: if the system only feeds a few 120V/15A circuits and stays under ~1,500W, 12V is fine; once you need 30A-class appliances, move to 24V; and once you are planning full home loads (50–60A demand), go 48V. The car-engine analogy in the comment is right — higher supply voltage means less strain on the inverter's internals — and the one thing we would add is that inverter longevity is another quiet benefit of going 48V.
@Kennephone · 58 likes
"The only problem with 48v is that there's basically nothing that can run directly on it, so you have to use the inverter all the time which decreaces efficiency. 24v is a happy medium between 12 and 48 as it allows more power, but most things that run on 12 will also run on 24, so it's good for an off grid cabin where the system is still small enough where every watt counts, but you need more power than 12v."
Our take: This is a legitimate and honest caveat, and it is why we always ask about DC loads before recommending a voltage. On a 48V system the inverter typically stays in the path for AC loads, and inverter idle consumption is a real efficiency cost on a tiny cabin. 24V does sit in a sweet spot when you need more than 12V but every watt of conversion loss matters. Our rule: if your cabin is genuinely small and DC-friendly, 24V is defensible — but if you expect to grow, the 48V default still wins on wire cost and headroom.
@thewowzach32 · 43 likes
"The hose analogy for volts, amps, and watts just cleared up something I haven't made sense of in 30 years lol"
Our take: Glad the analogy landed — it is the same one we use with customers who are new to solar. The pressure/thickness/volume picture makes volts-amps-watts stick far better than the textbook definitions, and once that clicks, the wiring trade-offs (higher voltage = thinner wire for the same power) follow naturally. For anyone who still finds it fuzzy, the practical test is simple: compare the cable needed for a 1,000W load at 12V vs 48V and the difference is immediately visible.
@Scott-ig1zd · 37 likes
"I built my system back in 2020 48v components were hard to find and expensive. Back at that time Will Prowse was recommending 24v system for medium system like my 250 square ft cabin. I bought a Big Battery 24v 170ah lifepo4 ,2000w inverter and 1000 watts of panels. I use it about it about 120-150 days a year and I'm using the exact system I started with and no down time."
Our take: Your 2020 build is a great real-world data point, and it also shows how fast the market moved. Three years ago 48V components were pricier and harder to find, which is why reputable voices recommended 24V for medium cabins; today 48V inverters, batteries and charge controllers are the volume products and the price gap mostly disappeared. If we were advising you now with the same 250 sq ft cabin and 2,000W inverter, we would spec 48V from the start — but there is nothing wrong with a 24V system that is already running reliably for years with zero downtime.
@junkerzn7312 · 24 likes
"Also charge controllers are far more effective at 48V than at 12V. A 20A charge controller at 12.8V can handle up to 256W worth of solar panels. That SAME controller at 51.2V can handle over 1000W (assuming a controller that does 12/24/36/48V of course, but many do these days). Just as an example. Convenient kitchen appliances... Microwave, induction tea kettle, toaster oven, induction "burner", well pump.... the list goes on. Best to just go straight to 48V (51.2V LiFePO4) in most situations. In fact, I would only consider 12V at far lower wattages than the channel recommends. If its less than 500W then 12V is an option. If its more, or you might scale higher than 500W, then I'd go straight to 48V. At 48V, 2 AWG main battery and inverter wiring nets you 100A @ 51.2V = 5000W of continuous power without anything even getting warm to the touch, let alone hot. And all the solar panel string and charge controller output wiring can be 10 AWG. The only real gotchas with 48V is that (A) You need to be a bit more up on your electronics skills. (B) Getting any fusing and breakers right is more important. And (C) you need to pay more attention the solar panel topology. The best charge controllers are buck controllers (Victron's for example) which means that to work properly with a 48V system the solar strings have to generate roughly 65VDC or higher "operating voltage". --- For string voltages I shoot for at least 70V. Higher if partial shading might be an issue. My go-to charge controller is thus something like a Victron 150/35 for the voltage range it supports rather than a Victron 100/20. A single 150/35 can handle 1800W worth of generation all by its lonesome. You can do this with any solar panel wattage but you need to figure out how many in series you need to get decent results, plus one more to help deal with partial shading situations. Even 25W panels would work, but you would need 4 x 25W in series to develop a decent voltage for a 48V system. Similarly for other small panels. When you get to more serious panels... 100W you typically need 3 x 100W in series (but if they are low-voltage 100W panels you'd still need 4). 200W panels you would also typically want 3 in series. Higher than that the voltages are higher so typically residential panels would need only 2 in series. My go-to is always 48V. I only consider 12V for very very small systems and only consider 24V in very special cases. My default is 48V these days. -Matt"
Our take: Matt's numbers are exactly right and worth underlining: the same 20A charge controller handles about 256W of panels at 12.8V but over 1,000W at 51.2V, and 2 AWG at 48V carries ~5,000W continuously without getting warm. His gotchas are the practical ones — more electrical skill, fusing/breaker discipline, and solar-string voltage planning (roughly 70V+ string voltage for buck charge controllers on a 48V system). We would add one simplification: if you are below ~500W, 12V is a fine choice; above that, go straight to 48V and avoid the 24V middle step entirely.
@paultech9385 · 23 likes
"One caveat to your skip 24V statement is if your setup is running DC load components w/o an inverter."
Our take: Good catch, and it is the one place the video's 'skip 24V' advice needs a footnote. If your build powers DC loads directly — 12V or 24V lighting, pumps, fans, USB-C hubs — with no inverter in the path, then 24V lets you run those loads natively and avoids conversion losses entirely. So the practical rule is: pure AC loads, go 48V; significant native DC loads at 24V, the middle voltage earns its place. Most builds are mixed, which is why we ask about the load list before recommending a system voltage.
@JRao · 20 likes
"Why does no one make a 120v battery?"
Our take: The short answer is that 120V DC is dangerous and impractical at the voltages batteries actually deliver. A 120V 'battery' would need ~32 prismatic cells in series, and any shock hazard above ~60V DC is a serious safety issue in a home. That is exactly why inverters exist: keep the DC side at a safe, efficient 48V and convert to 120V AC only where the wiring standards and breakers expect it. The industry settled on 48V as the high-voltage sweet spot — safe to work on with care, thin cable, and standard components everywhere.
@JeffPowers6995 · 17 likes
"What about safety considerations for the beginners that this video seems aimed at? Is it much easier to get yourself in trouble/danger handling 48V stuff? What are the most important safety cautions for the beginner? If that kind of info isn't in that playlist you mentioned, perhaps it would be a good candidate for another video."
Our take: Legitimate question, and the honest answer is: 48V is still safe for beginners, but it demands more care than 12V. The three cautions we repeat to every customer are: (1) always use insulated tools and remove jewelry — 48V won't kill you, but a short across a 51.2V pack can dump hundreds of amps and start a fire; (2) get the fusing and breaker sizing right on every branch; and (3) respect the solar-string voltage — if you are using a buck charge controller on 48V, the panel string needs to be around 70V+, which is a step beginners often miss. 12V is more forgiving for a first build; 48V rewards a slightly more careful builder with a much better system.
@FocusedHomested · 16 likes
"At $3600 each for only 280ah’s, those are some rather expensive batteries! Wiring for a 12v system may be a little more expensive but it’s also a 1 time purchase. For a little less money, you can get 4 of the 12v 280 ah batteries and a 5000w inverter and be running most of your house. Spend the money on a good solar or propane fridge and deep freezer, and move the heavy loads like washer and dryer over to a generator. It’s your money so spend it how you want, but if you’re on a smaller budget, 12v is way cheaper and will get you running and enjoying life"
Our take: Your cost logic is fair for a budget-first build, and plenty of off-gridders run happily on four 12V 280Ah batteries with a 5,000W inverter. We would only add the scale argument: if you already plan four 12V batteries in parallel, the same cells in a 48V pack use thinner, cheaper interconnect wiring and one 48V inverter, which usually closes most of the gap you are describing — and leaves room to grow. The fridge/freezer-plus-generator strategy for heavy loads is sound advice regardless of voltage, and matches how we size hybrid systems.
@ArizonaRegime · 9 likes
"I ran a 12V in my semi-live in van, If I did it again I'd likely run a 24V system, I wanted to run 12V due to the ease of running 12v outlets/lights internally, but most of these are available in 24V now and the wiring is much easier to deal with. Not to mention doubling my MPPTs output with 24V would be ideal. Overall I'm happy, I have the dometic 12v RTX2000 AC system, 1000W of solar, and 620Ah of battery bank, but the 24V system would allow me to do that much more easily, with a smaller MPPT and less wiring. The MPPT I am usiing cost about 380$ with 24V I could get away with cheaper wires and a ~100$ MPPT."
Our take: Your van build is a textbook example of the 12V vs 24V trade-off in the real world. The reason 12V felt easier — 12V outlets and lights everywhere — is exactly the reason it costs more: 12V needs fat cable for any real load. Today 24V lighting, USB and appliance options are much more common than they were, so the pain point you hit is largely gone. Your numbers (a ~$380 MPPT on 12V versus a ~$100 MPPT plus thinner wire on 24V) are the clearest illustration in the thread of why medium systems are drifting to higher voltage.

Source video: The Solar Lab — “Which is Best? - 12 vs 24 vs 48 Volt Solar Batteries Explained” (youtube.com/watch?v=0vq9JnA_-cI). Comment excerpts are quoted verbatim from the video’s top comments; creator replies are quoted where they exist, and unanswered threads carry Dajiu Energy’s own answers. 380K+ views. The Solar Lab breaks down 12V, 24V and 48V solar battery systems with a simple volts/amps/watts analogy, covering wire gauge, cost and exactly which voltage fits which size of system.