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How we test portable power stations at ZDNET in 2024

We've tested over 100 portable power stations in recent years. Here's how we make sure they're worth recommending to you.
Written by Adrian Kingsley-Hughes, Senior Contributing Editor
DJI Power 1000

Testing the DJI Power 1000 power station.

Adrian Kingsley-Hughes/ZDNET

Remember those bulky power banks that could barely keep your phone charged? Forget them! Power stations are the new rockstars of portable electricity. In just a few years, they've exploded in popularity, transforming from niche products to a dazzling array of options.

Now you can find everything from compact, grab-and-go systems perfect for camping adventures to heavy-duty units that can keep your entire house running for days during an outage. And the best part? The price range is incredibly versatile, with options for nearly any budget, from a few hundred bucks to several thousand dollars.

Also: Best portable power stations of 2024: Expert tested

But if you're dropping hundreds or even thousands of dollars on a system, you need to ensure you're getting the best possible value for your hard-earned cash. That's why, here at ZDNET, we go to great lengths to put each and every power station through a barrage of tests. 

How we test portable power stations in 2024

Over the past few years, I've tested well over 100 different portable power stations to find out which are the best of the best. To do this efficiently -- because it takes days to do properly -- I've developed a comprehensive testing structure. This not only ensures that manufacturers aren't playing fast and loose with their spec sheet data, but also checks whether the units are safe and reliable. Here's how we test portable power stations.

What makes a power station ZDNET Recommended?

There are many factors to consider when it comes to recommending a power station, and we believe readers deserve the best possible power station for their money.

First and foremost is safety. No matter how good something is, if it's not safe, it doesn't make the cut.

Next, it's vital that the power station delivers on its promises. If we can't trust manufacturers to be honest about the specs, we can't trust them on anything else.

After that, it's about balancing other factors like capacity, cost, and features. It's all about finding the right mix to ensure you're getting the best bang for your buck.

Unboxing and visual inspection

It all starts with a visual inspection. Even the smallest power stations are weighty bits of kit, and some of the bigger units can weigh 70 pounds or more. That's a heavy object to be bashed and banged about by couriers, so the packaging needs to protect the precious cargo. I start every test with a detailed visual inspection, checking for signs of physical damage, loose components, or more subtle issues like crushed cables. This might seem basic, but the last thing I want is to plug a box packed with lithium batteries into the mains and have it do something unpredictable.

Capacity tests

Next, I plug the unit into the main AC and conduct a first charge. Units normally ship with about a 50% charge, so this is a top-up. 

This is also a good time to check that all the LCD panels, buttons, and ports work and to download any associated app to link the power station to my smartphone. 

When the unit is charged, I use a few discharge/charge cycles to properly condition the batteries. I'll hook up a modest load to the system -- a 500W floodlight if the unit has AC outputs, or some of my bigger power banks if the unit only has USB-C -- to discharge the system completely between recharges. To find out the true capacity of a system, I use power meters to measure how much power the unit consumes to recharge. I'll conduct these tests a few times to ensure the results are consistent.

Load testing

It's important to test the outputs of all the ports. To see how much load the USB ports can handle, I use a combination of USB power meters connected to high-power USB devices (laptops, phones, power banks) to stress the ports. 

Overloading the Power 1000 with a toaster

Overloading the DJI Power 1000 by connecting it to a toaster.

Adrian Kingsley-Hughes/ZDNET

For AC power, I use a range of household appliances such as a light, kettle, toaster, and heater to keep things as real-world as possible. These loads help me ensure that the unit is capable of its rated power output for sustained periods and can handle being pushed beyond its rated surge load. I look for a graceful shutdown when overloaded.

UPS capability testing

If the manufacturer claims that the power station can be used as a UPS (Uninterruptible Power Supply), I'll test this feature by connecting a power-sensitive load (a desktop PC is good for this test), having the power station connected to AC mains, and then cutting the power. If the power station can handle the switchover, it passes the test.

Thermal tests

I use a thermal camera to scrutinize the whole power station, along with the cabling and any external power supplies, for any hot spots that might suggest a potential problem. Weather permitting (I am in the UK after all), I leave the power station to work out in the sun to see how it handles being exposed to, and working in, direct sunlight.

Safety tests

When dealing with what is essentially a box filed with rechargeable batteries, safety is my number one priority. I carry out a series of  visual inspections and electronic tests on every power station (and associated accessories) to make sure it conforms to electrical safety standards.  These range from checking the plugs, leads and sockets to injecting test signals into the cable and appliance to ensure their integrity.

Real-world usage

There's nothing like taking power stations outside to really test their robustness!

Adrian Kingsley-Hughes/ZDNET

While carrying out tests to make sure the numbers on the spec sheet match real-world performance is essential, nothing beats actual usage. It's here that we truly measure how these power stations perform. I replicate two kinds of usage scenarios. The first is home usage, where you leave the device plugged in and charging, ready for a power cut. Power cuts are rare where I live, but I can easily simulate one. It's kind of fun to run your whole life off a power station for a few hours, or, in some cases, a few days.

The second scenario is off-grid usage. This involves bundling the power station into the back of a car or truck, driving it across dirt roads, and carrying it through whatever Mother Nature throws at it. I then use it for a few days to charge things like cameras, drones, and laptops. You can learn a lot about a device doing this, and it's really helped me separate the wheat from the chaff. Some power stations seem great indoors, but once you take them into the great outdoors, they can start to get flaky and unreliable.

By combining these rigorous tests with real-world scenarios, I ensure that the power stations I recommend are truly the best of the best.

Solar charging

For solar generator systems, I like to try to test solar panels, to find out how well they work to charge the power stations. Now, as I've already mentioned, I live in the UK, so the sun isn't always going to cooperate. However I've found that even the weak UK sun is pretty effective when using modern solar panels, and I found that I can get decent outputs from March through to about October.

Other observations

As I use the power stations I'm testing, I look for a few things that can affect their usage. 

For example, is the LCD display readable in bright sunlight, are the handles comfortable to use, or are the port covers fiddly or delicate or fall off after a few uses? These can be deal breakers and worthy of note. Because if you're going to be using your power station outdoors or carrying it any significant distance, or need the port covers to protect the unit from dust and dirt, these things may matter to you.

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