Charging Bluetti EP500 Energy Storage System With Solar Panels & Grid – CleanTechnica

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A couple of months ago, I wrote a review of the Bluetti EP500 Pro energy storage system. As a Floridian, it hit me after a particularly bad hurricane in 2022 that I should have a backup power source for when the next bad hurricane hits and we lose electricity for an extended period of time again. Bluetti was kind enough to send over the EP500 Pro (a $3,999 retail value) for extended review. Bluetti also sent over the complementary solar panels later on. Here’s my take on the solar panel portion of the package after a couple of trials.

I was particularly excited about the solar panel package ($1,498 retail value right now — $749 per solar array with a $100 discount) since I wanted to power the energy storage system with 100% clean, renewable, solar energy. Unfortunately, I discovered that’s a little harder than expected.

Starting with opening and connecting the solar panels themselves, that was actually quite easy. The cords provided are super clear and easy to connect. The panels themselves are truly portable and manageable. But there was one challenge.

As you can see in the picture above, there are little fold-out backstops on the back of the solar panels. Pulling one of them out is easy enough, but they don’t then lock into place there. They hold fine once they are all standing, but to open all four panels out, it’s challenging to get them each to stay standing as you pull the stand out for the next one and the next one and the next one. The ones you pulled out first very easily slip back against the back of the solar panel as you’re trying to open the next ones.  It’s clunky. Naturally, this is not the end of the world and it’s manageable, but it’s certainly not ideal. Doing the job with two people makes it much easier, but it’s still not perfectly smooth and simple even with two people wrestling with the PV350 solar panels.

Once you do get all of the stands open and the panel array standing, it works well. It is stable and strong. Again, though, if you need to move the array a bit, it is a little challenging since lifting it even a tiny bit can lead to the backstops snapping back into their original positions flat against the back of the panels. I am surprised there’s not some locking option.

What I will say is that I love the easy and elegant way in which the solar panels fold up and then get wrapped up in their own backings without any extra cover. They end up looking like art portfolios or special travel cases. They are surprisingly heavy compared to how they appear in this state, but I’d say they are fine — not too heavy. They are probably a pretty ideal balance between solar capacity and weight.

That said, charging up the EP500 Pro with these solar PV panels is a different kind of challenge. I first tried doing so one afternoon on our back patio — with sunlight coming in but through a typical Florida pool/mosquito screen (we don’t have a pool, but we do have mosquitoes). It just wasn’t working. The sun wasn’t steady enough or strong enough through the screen, and the energy storage system was actually gradually losing electricity simply from being on outside and needing to cool itself, and not getting more electricity from sunlight to surpass those needs.

So, I took them out another day and put them in our driveway, where the screens wouldn’t interfere. Unfortunately, while it is indeed the Sunshine State, it wasn’t the sunniest day. It was a bit overcast, and I ran into the same problem as before. They did charge up the energy storage system for a little bit, but after a few percent of added charge, the system just stalled at around 20%. I moved the panels around to try to keep them in as much sun as possible, but there was just a bit too much cloud cover and too much extra shading from a couple of small trees. After about two and a half hours and no progress for most of that, I gave up.

As you can see in the following picture, I wasn’t getting anything close to the 700-watt max I should be able to get from the two arrays (350 W each). At the moment I took the picture, I was actually pulling in more power than I was most of the time — 194 W versus something around 100 W. Overall, though, the efforts just didn’t cut it. I was stuck at about 20%.

Now, if we were in a genuine after-hurricane situation, I do think these would still be useful. There are two types of weather you get after a hurricane passes over. You can still get bands of rain at times, but much of the time, you get super clear skies — the hurricane has sucked the clouds into it and leaves sunshine behind. So, I imagine I’d have great conditions for recharging the EP500 Pro with the PV350 solar panel arrays right after a hurricane, when I’d need the solar energy the most. (Stay tuned — maybe I’ll get to test this out for real next year!)

You can also charge the EP500 Pro with a simple electricity plug via the grid — via a normal 120V electricity outlet. That works really fast. You can charge the whole 5120 Wh energy storage system in just a few hours. For comparison, you can see two pictures below from me charging the system this way. The first picture shows the system at 7% state of charge, and the second picture shows the system 43 minutes later at 30% state of charge. So, charging a quarter of the battery takes around 45 minutes.

Naturally, this is not for everyday use. It’s for emergency backup power. (Though, if the solar panels collected sunlight and turned it into electricity a bit better, I’d probably use the energy storage system to power my computer and phone on a regular basis.) I think it’s a pretty ideal system in terms of size, including weight (it shouldn’t be any heavier) and energy storage capacity. I definitely wouldn’t want it to be any heavier since you already have to be super careful with any lifting to not put your back out, and I think there’s ample electricity supply in the system. Similarly, while it would be nice to have more and better solar panels, in an emergency after-hurricane situation, I think these will work well and are the perfect balance of weight and size (I don’t have unlimited storage space) and power capacity. Naturally, if Bluetti can offer solar panels that are twice as efficient or work better in low-light conditions, that would be even better, but this should do for now.

If we ever get hit with a severe hurricane and extended power outage, or I just have a free very sunny day, I’ll review the system again and let you know how it goes. In the meantime, the EP500 Pro is resting in the air conditioning inside the home and the solar panels are neatly tucked away in the garage between a lot of tennis gear, some beach stuff, and a level 2 EV charger I need to test one day.

Also see: This Bluetti Energy Storage Backup System Is Smooth & Superb — I’m Ready For Hurricane Idalia!