EcoFlow PowerStream Review: The World's First "Balcony Solar Plant"

Don't have room for rooftop solar and battery installation? The PowerStream might be just what you need: a cost-effective and DIY installation.

If you have a big EcoFlow battery, you've probably been making great use of it during your travels. You've probably even have some EcoFlow solar panels to charge it with unlimited free energy—perhaps some flexible panels mounted to the roof of your RV. But the rest of the year, they sit idle. What a waste! If only there were some way to make use of these panels to feed your home electrical system in the day, store any excess in the battery, and discharge that to your home overnight, saving you hundreds of dollars a year on your power bill. That sort of system would pay for itself in a few years.

That's exactly what the EcoFlow PowerStream is. And they're pitching it under the moniker of a "balcony solar power plant".

The EcoFlow PowerStream provides a small-scale way for your home to benefit from solar energy and battery storage, integrating with smart plugs that measure required power. Despite a somewhat tedious setup, it offers a cost-effective way to benefit from solar even in a small space or rented buildings.However, it may not suit everyone with its limited configuration options, and if you have a larger space to mount rigid panels or don't want battery storage, you could get better value from a standard micro-inverter.

You’re going to see a few of these available this year from various companies, but this is the first, so it's worth exploring what the term Balcony Solar Plant even means. In short, it's a small-scale grid-tied solar and battery backup system.

Whole home batteries and rooftop solar systems are a big investment and of course, require a roof and a house. If you don't have $20k to spare, or you live in rented accommodation or an apartment, you might be wondering if there's anything a little less grandiose. That's a Balcony Solar Plant.

This will typically consist of:

A Balcony Solar Plant is unlikely to power your entire home (for most people, anyway). But it will lower your electric bills dramatically by storing solar at times when you have too much, and feeding it back when needed.

The other huge benefit of a Balcony Solar Plant is that it doesn't require planning permission, export consent from your energy provider, or any other oppressive certification (except in Germany, where it seems you still have to register to use this, and output is limited to 600W).

In theory, you won't be giving any power back to the grid, as it should all be used on-site. Or at least, you can set it up that way if needed. And of course, it’s completely DIY, so you don't need to pay an installer and ican be up and running in less than an hour of unboxing the device.

The EcoFlow PowerStream is compatible with most EcoFlow batteries which include an expansion port on the side, but you should check before purchase, or buy in a bundle that includes everything. We were sent a Delta 2 Max to test with this, which is 2kWh, but if you wanted even more capacity, a Delta Pro would be best with 3.6kWh.

Of course, the larger the battery, the better performing your system will be. The more power you'll be able to store overnight.

As for solar panels, of course, it'll work with EcoFlow portable, rigid, or flexible panels. We were sent a set of four flexible panels to test with this, but it'll also work with solar panels from any manufacturer that have an operating voltage in the range of 11-60V and a maximum of 13A. The EcoFlow PowerStream has two solar inputs, each of which is limited to 400W. So that's up to 800W combined.

Something else you might want to pair with the PowerStream is the EcoFlow Smart Plugs. These can detect the load of whatever you have plugged into them, and the PowerStream will automatically direct power to your home when needed to power those devices.

Measuring 242 x 169 x 33mm (9.53 x 6.65 x 1.3 inches) and weighing about 3kg (6.62lbs), the PowerStream is a very stylish flat metal box, and as far as I can tell, has no active cooling systems.

You can have a maximum of 800W of solar input, as well as 600W in or out to the connected battery. The AC output is up to 800W. It's not a massive amount of power, so it ultimately limits its use to relatively small-scale apartment living. I hope in future they'll release a larger rated one.

Physically setting up the EcoFlow PowerStream is trivial, with three large cables you'll need to plug in.

One of these goes to your solar system. This cable has two sets of MC4 tails, and you'll want to work out the best way to cable in your panels according to the output voltage and current, bearing in mind the 11-60V, 13A, 400W limit on each.

Another cable goes to your battery. In our case, that's a Delta 2 Max. This cable is not included unless you buy a set bundle, and there are a few different types of cable allowing it to work with different EcoFlow batteries, so you'll need to ensure you buy the right one if you're making a customized install.

Finally, the AC connection. This should go directly to a wall socket—not an extension lead, and definitely not to another battery.

Other than those cables and then mounting the box if needed (a rear mounting plate is supplied, as well as a protective cover), the rest of the setup is done in the EcoFlow app.

One option is to mount the PowerStream outside. It’s IP67 rated weatherproof, so if you have a covered AC power socket it can plug into, that's possible. However, if you're using a battery, the connector cable is too short, and the batteries aren't waterproof.

If you live in rented accommodation, you might be wondering how to connect your balcony solar panels to this without needing to drill holes or leave the window open. EcoFlow has thought about this too: you can purchase optional flat MC4 solar cables, which will happily mold around your window frame and still allow the window to close. I used this to pull another line through the window—it’s a standard uPVC double-glazed window, and it still locks fine.

As mentioned, the PowerStream is compatible with a wide range of solar panels, and we were sent a set of four flexible panels to try. These can be split across both input chains in pairs, or connected to only one of the MC4 tail sets from the power stream box—but due to the voltages they produce ([email protected]), you must be careful to do this in two parallel sets of two panels in series. You'll need some Y-adaptors to do so, which are sold separately.

I mounted these as I thought the average apartment dweller might, by cable tying or screwing them onto the decking here. The angle isn't ideal, but I wanted to see how they would perform in less-than-ideal conditions, as you may not have a huge amount of space to work with. In full sun, they peaked at just over 200W total.

If you have more space to work with, it's worth getting larger rigid panels instead. The super value bundle that EcoFlow offers comes with two rigid 400W panels. I have a couple of 550W Canadian panels, so I hooked up one of the solar input channels to one of these. The voltage is within specification, and our weather means they would rarely exceed 400W, so this was a good chance to test the PowerStream box to its limit.

Once you're plugged in with things mounted, you'll have to initially add all the individual parts to your EcoFlow account in the app. Each smart plug, the PowerStream, and the battery will all need to be added one by one, and you'll likely need to upgrade the firmware. It's quite tedious, especially if you don't have an account already and need to do that first, but it's not a difficult process. Be sure to have your home Wi-Fi details on hand too, as all the EcoFlow devices use Wi-Fi for remote control and access.

Once all that's done, jump over to the PowerStream device page. Here you can see an overview of the power flow around your home.

There are two operating modes for the PowerStream, called prioritize power supply and prioritize battery charging. If you choose to prioritize power supply then it's going to try to supply what you ask for, both from the smart power plugs and the base load you set, even if that means depleting the battery during the daytime. In prioritize battery charging mode, the PowerStream will make sure it charges your battery first before feeding excess back to your home.

Those two options are not ideal all the time, which is where the next key part of the equation comes in: scheduling. From this screen, you can tell it to enable particular modes at a particular time, most likely to prioritize power supply and use the battery at night, but prioritize the battery charge during the day. This is ideal for me, as I have drastically different power rates for a few hours at night (12 cents vs 50 cents). I don't want to discharge from the battery during these hours, as it's more financially sensible to use the grid power. It would be nice if I could top up the EcoFlow battery during these hours, too, but that's not an option on the PowerStream currently.

The other important thing to configure is the base load of your home, which the EcoFlow refers to as "power demand from other loads". This is how much power your home uses all the time when demand loads are turned off. Things like your router, or refrigerator. These sorts of things all contribute to a base load; they’re not things you would usually turn off and on, so there’s no need to measure the usage with a smart plug. You can also leave this as zero if you only want to power devices you can actually measure the usage of with the EcoFlow smart plugs, but this means there may be times when you could be generating power, but aren't because it has nowhere to go.

Hopefully, your base load is fairly low because this is only a small-scale system. If you're using too much base load then the benefits are going to be much less.

Whatever you set here as the base load is going to be constantly fed into the AC from this PowerStream when you have it set as supply priority. And that applies at daytime with excess solar or from the battery at night. It will always feed that much into your home when that setting is on.

On top of that, you’ll have demand loads, and these are short spikes of power usage that you can measure using the optional smart Wi-Fi plugs. So if you plug your big gaming PC into this which draws 500W when you switch it on, your PowerStream will immediately divert 500W of power from solar and the connected battery to your home to counteract the usage from the device you just plugged in. You could, of course, also use plenty of Wi-Fi plugs to measure the baseload of your home, but if it's a constant value then you may as well set it as a base load, and use the plug elsewhere. The smart plugs can also have their own scheduled time on and off settings, but there's no way to turn them only when excess solar is generated.

You don't have to be too precise or worry if you're not generating enough, or if the battery is empty. As a grid-connected system, it's going to work on a best-effort basis, meaning if it can provide power for your base load and measured appliances, it will. If not, your household sockets will continue to work as they always have, drawing from the power grid.

Right now, there aren’t a lot of Balcony Power Systems released yet. In fact, EcoFlow is calling this the world's first, though I have been approached by other companies letting me know they’ll have ones later in the year too.

But as for how the EcoFlow PowerStream compares to other inverter systems—it sits somewhere between the incredible smarts of the Tesla PowerWall, and the basic dumb micro-inverter systems that you can find on AliExpress. I have all of these installed at home, and they can happily operate together along with the EcoFlow PowerStream, so I can confidently speak to how they compare.

The Tesla PowerWall doesn't just do energy storage and solar, but will also intelligently charge from the grid overnight if it predicts cloudy weather or if it would be cheaper because you have overnight tariffs. It will also deliberately charge fully if it knows a storm is on the way. A Tesla PowerWall also knows the exact load your home uses at any time because it's wired directly to your home circuits.

On EcoFlow PowerStream, you have to manually set a base load of how much you want fed in at all times, then add intelligence to the system via smart plugs. This is great for a small apartment, allowing you to effectively make perhaps gaming PC or TV completely solar-powered. But it's impossible to link the PowerStream into your home circuits entirely with a power clamp to measure whole home usage—it has to all be done with a dumb manual input setting or with the smart plugs.

You'll also battery-less micro-inverters relatively cheaply, such as the model pictured above from AliExpress. Aside from a local Wi-Fi connection that you can download generation data from, it doesn't have any smart features. You can, however, attach a current measuring clamp to your home circuit, and the box will ensure you don't export any excess—only as much as your home is using. A current clamp is a very low-tech solution, but it works, and it's curious that EcoFlow doesn't offer the option for the PowerStream, instead forcing you to use smart plugs.

In my experience, the PowerStream is a fine balancing act. It has its use cases, but I can't help thinking it needs a few more smart features to avoid wasting solar power—at least for me.

For instance, when you have plenty of solar, the battery charges. Great. But when the battery is full, and your smart plugs aren't registering a demand load, and your base load is set low, there's no option to dump all the excess into your home AC socket. This wouldn't be legal in some places as you'd need an export license. But there's no option to do it, regardless.

One way around this is to increase the base load setting. That works—until there's no more excess solar, and at power supply priority times, that high base load will continue to be fed in coming from the battery instead of solar, depleting it in a couple of hours.

So the base load setting should be optional, with the alternative being to dump any and all excess into your home. The smart power plugs would still be used to draw from the battery when demand is created at any time of day, but that would alone would be a big improvement for me.

Also, we experienced one critical bug with the EcoFlow PowerStream. On one particular sunny morning when it should have been generating, I found the PowerStream to be functionally dead. It was all plugged in and accessible over Wi-Fi, but the battery was drained and solar was registering as no input. I had to unplug and replug the solar to kick it back into action; had I not have been reviewing the device, I wouldn't have even noticed.

When I emailed support I was told that you shouldn’t leave the panels plugged in overnight because it will potentially drain the battery and enter this dead state until restarted. This is absurd. It might be a micro-inverter, but that doesn't mean you should be micro-managing everything. Any other micro-inverter will draw a little from the grid overnight to keep its circuitry going. It's such a small amount that it's covered many times over once solar starts generating. Hopefully, our support representative misspoke, but we were promised a technical fix that still hasn't materialized.

If you already have a battery and solar panels, the PowerStream box alone will set you back around £350, which is about twice what I'd expect to pay for a superficially similar basic micro-inverter box on AliExpress. Admittedly, that wouldn't have the EcoFlow app's smart plug integration or battery charging capabilities, so it's not an entirely fair comparison. I think the price difference is therefore justified, and it's good value for money for the features offered. Considering my extortionate power rates, the box would pay for itself within a year or two, even if it only saved 2.5kWh of power a day, which it would easily do with 800W of panels connected.

In fact, you can get even better value if you buy it as a full set. The recommended 2kWh Delta 2 Max battery storage, two rigid 400W panels, the PowerStream, the correct battery cable, and two smart plugs, costs £2367 at the time of review. This elevates it from a reasonable price to a bargain. It may take 3-5 years to get that sort of return, but of course, after that period, you're getting free power.

If you don't already have an EcoFlow battery and weren't planning to get one, then you might want to look at a generic micro-inverter box instead and pair it with whatever panels you already own. Alternatively, you could buy some cheap rigid panels if you have the space. It won't be nearly as smart and you won't have the energy storage, but it will mean you pay back your investment quicker without that smart premium. The 800W total solar input on the EcoFlow PowerStream is on the lower end, so if you have a little more space to mount some larger panels, you could double your potential generation for the same price as the smaller EcoFlow system.

James has a BSc in Artificial Intelligence and is CompTIA A+ and Network+ certified. When he's not busy as Hardware Reviews Editor, he enjoys LEGO, VR, and board games. Before joining MakeUseOf, he was a lighting technician, English teacher, and data center engineer.