EG4 18kPV Inverter Review – Is it Still Worth it in 2025?

Jan 14

The EG4 18kPV Hybrid Inverter was considered to be EG4’s most powerful and user-friendly inverter—until the FLEXBOSS 21 entered the scene. Even with its newer, flashier brother now on the market, the 18kPV remains a robust option for anyone in need of a reliable hybrid inverter.

But does the EG4 18kPV still hold up in 2025? Let’s dive into the specs, features, and real-world performance of this unit to see if it’s still worth your hard-earned money.

EG4 18kPV Hybrid Inverter Overview

Before we dive into what we like and dislike about it, it’s always a good idea to break down what this unit was designed for and what specs it offers.

The 18kPV is a 48V split-phase hybrid inverter that’s capable of running off-grid, in grid-assist hybrid mode, or even as a grid-connected unit that allows you to sell power back to the grid for net metering purposes.

Specs Breakdown

Here’s a quick look at its specifications and features according to EG4:

Weight: At roughly 111 lbs, this thing is a beast and just barely passes the Tiny Baby Lift Test. While we were able to mount it solo by using a sort of awkward squat lift, you’re probably going to want some help during installation.
Solar Input: As the name implies, it has a hugely impressive 18kW solar input, which was only recently bested by the FLEXBOSS 21’s 21kW PV input. The 18kPV’s three MPPT charge controllers also allow it to function as a split-phase inverter, meaning it supports 120V and 240V configurations.
Continuous Output: It can deliver a continuous 12kW output, with a surge capacity of 15kW for up to 5 minutes. Having the ability to withstand such lengthy surges is really useful for situations where you’re looking to supply power to appliances and power tools that have high start-up requirements.
Parallel Capability: You have the option to connect 10 units for a combined output of 120kW. This crazy level of scalability means it can grow with you as you expand your system. While ten of these things might only be necessary for large scale commercial and agricultural setups, having the option to double your input and output by picking up a second unit is really useful.
Efficiency: It’s rated to have an efficiency of 97.5% when converting solar to grid power, which is also really impressive. This is the type of thing that is really beneficial for those looking to sell power back into the grid.
AC Bypass Breaker: 200 amps, enabling rapid battery charging.
Weatherproof Design: NEMA 4X rating for outdoor use, so you don’t have to worry if you install it in a garage or shed with minimal weatherproofing.
Price: At $4,848 (with our discount code), it’s definitely not cheap, but as we’ll explain, we think even at that price point, it still offers plenty of value.

Real-World Performance Testing

While it doesn’t hold the title of “biggest” anymore (thanks to the EG4 FLEXBOSS 21), it’s still a powerhouse. We’ve had our hands on it for quite a while, so we’ve had plenty of opportunities to see how it performs in the real-world. So, let’s see how it has stood up to our extensive testing:

Testing the Output:

The EG4 18kPV effortlessly powers large appliances, including air conditioners, refrigerators, and power tools, without any hiccups. We have it installed in our garage, so we regularly use it to run space heaters, power tools, and more.

The fact it’s a 12,000W rated inverter and actually delivers that output shouldn’t be taken for granted, as we’ve come across plenty of pieces of solar equipment that haven’t delivered on their advertised specifications.

We’ve also noticed that it also comes through on that 5-minute 15.5kW surge rating EG4 advertises. When we’ve used it to supply power to appliances with really high start-up power requirements, like the massive 15kW Dyna-Glo heater we have in the garage, it always handles them with ease. It can even do this when it’s running purely on battery power—no grid power, no solar power, just purely what power it has available through stored battery power.

While we don’t have one of the huge 5-ton air conditioners some people use down in warmer states, so we can’t really test that, we’d have to guess that it would struggle if you weren’t running more than one unit in parallel.

Still, it still easily handles the basic air conditioner unit we have hooked up to the garage for when we’re working out here in the summer, as well as a wide range of more demanding items, like our heavy-duty compressor.

Another thing we have found after using this inverter on a regular basis is the fact that it does not seem phased when we are running multiple loads at the same time. This is really crucial for those planning to use it as a fully off-grid power source, as you could run multiple household appliances simultaneously.

Idle Consumption:

When you’re looking to invest in a new inverter, one of the more important factors you should consider is what the unit’s idle consumption looks like. Basically, idle consumption is how much power the inverter uses just to stay on, even if you’re not directly using it.

We found that the 18kPV uses about 60 to 70 watts and usually runs somewhere in the region of 1.2 amps while it is on the battery. This is actually really good, especially when you consider the fact that some of the much smaller units, like the little entry-level EG4 3,000W Inverter, use about the same when idling.

Still unsure what this means? In short, more of the power your system generates will be available to run your equipment, or sell back into the grid, rather than being wasted just to keep the inverter’s internal processes going. A good idle consumption is a really significant selling point, even if it is one that is rarely discussed.

Battery Charging and Solar Input:

Thanks to the 200-amp AC bypass breaker, battery charging was rapid and efficient, even under high load conditions. It’s rated to pass 12,000W from the inverter to your batteries, and when we’ve tested it, we got it right up to 11,400W, so all good there.

The solar input for this unit is crazy! We have a really solid solar array in the backyard, which generates more than enough power to charge up our EG4 Wall Mounted PowerPro Batteries. Despite this, we have nowhere near enough solar panels to come anywhere close to the 18kPV’s maximum solar input.

What We Like About the EG4 18kPV Inverter

Now that we’ve gone over the basics, let’s explain all the reasons why we’d still recommend picking this unit up. After we’ve covered that, we’ll also highlight a few of the minor gripes we’ve encountered.

The Oversized Solar Input:

The 18kW solar input that gives the 18kPV its name is a major advantage. With its 12kW output, you can power your loads at full capacity while still charging your batteries with the remaining 6kW of solar coming into the unit. This setup ensures you’re maximizing your solar production, even when running your system at “full tilt.” If your

batteries are fully charged, you can also sell excess power back to the grid.

Having such a massive solar input also means that you can continue to expand your solar array in the future, without needing to upgrade your inverter. We’re always fans of equipment that can grow with you as you invest more money into your system, so the crazy high solar input is a huge advantage.

The User-Friendly Touchscreen:

Compared to older models like the EG4 6000XP, which featured clunky interfaces, the 18kPV’s touchscreen is a breath of fresh air. Honestly, it’s one of the best display screens we have ever come across on any piece of solar equipment. The display is intuitive, easy to navigate, and even includes a built-in FAQ section and setup instructions.

In fact, the display made setting up and configuring the unit so straightforward that we didn’t even need to crack open the instruction manual!

Clean Wiring Options and Easy Installation:

The inverter features numerous punch-outs for wiring on both the bottom and back of the unit, making it easy to achieve a tidy installation. Whether you’re using a combiner box or running wires out the back for a minimalist look, this unit’s design accommodates your preferences.

We already mentioned how straightforward the setup was thanks to the user-friendly display, which walked us through everything step-by-step. As for mounting this heavy-weight, we’d have to say it’s a job for two people, but it wasn’t overly difficult.

On top of all that, its weatherproof rating ensures it’s even ready for outdoor setups. We have our unit inside a garage, but it’s always nice knowing your equipment isn’t going to fry if there’s a leak or something like that.

Built-in Disconnects and Breakers:

All necessary breakers and disconnects are integrated into the inverter, including a solar disconnect. This convenience eliminates the need for external components, which is a hassle you have to deal with when you look into some of the competing models. This simplicity is another huge plus for those looking for a clean setup inside their home.

Separate Grid and Generator Inputs:

Unlike the FLEXBOSS 21, which requires you to use a GRIDBOSS accessory for separate grid and generator inputs, the 18kPV includes these connections as standard. This feature makes it a simplified and versatile choice for hybrid or off-grid applications.

Low Idle Consumption:

Despite its size, the 18kPV’s idle power consumption is comparable to much smaller inverters like the above-mentioned EG4 3000W Inverter. This efficiency minimizes energy waste both when the inverter is under a load or just sitting dormant. In other words, more of the power you pull from your solar panels or the grid is usable.

What We Didn’t Like

Of course, no product is perfect, and the 18kPV has its quirks.

The Fan Noise:

The fans are a bit loud, creating a sort of weird grumble when the unit is running. It might sound strange, but it’s actually kind of reminiscent of the sound the Dementors make from the Harry Potter movies.

While this isn’t a dealbreaker, it’s something to consider if you’re installing the unit in a living area. We have ours mounted in the garage, so it really isn’t a big deal, but we’d probably grow tired of it if we had it in a confined space, like an off-grid cabin or something.

The Useless Handles:

The side handles look functional but they’re brutal if you’re using them to lift the unit. Save yourself the trouble—and some pinched fingers—by just supporting the unit from beneath when you are lifting it.

Again, it’s a minor gripe, but it’s worth mentioning, especially given how easy it would have been for EG4 to just equip it with more legit handles.

The Price Hasn’t Come Down:

At nearly $5,000 (even with our discount code), this inverter isn’t cheap. We were hoping the price would come down with the release of the FLEXBOSS 21, but that doesn’t really seem to be the case so far. It’s cheaper, but not by much.

With that said, it’s a really capable inverter that would work really well for a lot of people, so it’s not like it’s a rip-off. From our perspective, its features and impressive performance help justify the cost.

How It Compares to the EG4 FLEXBOSS 21

The FLEXBOSS 21, EG4’s newer hybrid inverter, boasts a higher power capacity and additional features, but it also comes with a steeper price tag. While the EG4 FLEXBOSS 21 is undoubtedly impressive, the 18kPV still holds its own for those who don’t need the absolute latest and greatest. For those looking for a smaller and cleaner-looking inverter, the 18kPV might even be the better option.

If you’re unsure which unit is right for you, we’d probably just recommend giving Signature Solar a call. We’ve mystery shopped them in the past and were really impressed with how helpful their support line is.

Our Final Verdict: Is the EG4 18kPV Still Worth It?

From our perspective, the EG4 18kPV Hybrid Inverter remains a strong contender in 2025, especially for users who value its oversized solar input, intuitive interface, and built-in convenience features. While the FLEXBOSS 21 may have stolen the spotlight, the 18kPV offers a compelling balance of performance and value.

With any luck, EG4 might even drop the price a bit now that they have a bigger unit available, so we’d recommend keeping an eye on that.

If you’re considering this unit, make sure to check out our reviews of other EG4 inverters, like the EG4 6000XP and the EG4 FLEXBOSS 21, as it will help you decide which of these units best fits the needs of your setup. If you’re still feeling confused, just give Signature Solar a call—they’ll help you make the right choice.

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