KUXIU S2 review — the solid-state MagSafe battery you didn't know you needed

There are certain things that you just need to be simple.  It’s frustrating to buy a multi-monitor setup for your laptop only to end up with another power brick and another two to three cables wired into your laptop sides.  Similarly, it’s a pain to pick up a battery solution that’s meant to be compact, only to end up with a dangly cable that makes it easy to snag if you pocket it.  Yes, there are plenty of MagSafe batteries out there, but I’ve recently gotten my hands on one that not only solves the simplicity problem, but also solves a much more dangerous problem as well.

It seems like every other week there’s a report of a battery swelling up, or worse, exploding and catching fire.  It gets a little more scary when it happens at 30,000 feet in an airplane.  The problem with the vast majority of batteries is that they are made with Lithium-Ion, and over time they can become damaged through normal use.  Overcharging (charging too high),  over-discharging (discharging too close to zero), excessive heat, and just age and time can cause electrolytes to break down inside the battery.  These batteries are designed to have a separation between layers, but as these layers break down or the electrolytes degrade, it can turn into a blend of oxygen, carbon dioxide, and other gases.  These batteries are sealed, so those gasses have nowhere to go. The battery swells, and if ruptured, it can cause a fire or even violently explode.  Battery manufacturer Kuxiu has been researching a way to solve this issue, and with their magnetic solid-state power bank, they’ve actually done it. 

The S2 Magnetic Solid-State Power Bank may not be the most exciting product name, but I’m very excited for what it does and what lies underneath.  The exterior is a precision CNC-machined, sandblasted, and anodized aluminum case, wrapped with double-sided American Corning glass, and reinforced with an explosion-proof film to top it all off.  This heavily-reinforced case protects it from the most extreme conditions.  The team demonstrates this, rather violently, in the video below: 

As you can see, this device can be hammered, punctured, awl-punched, cut, stabbed, and even ripped at with a pair of wire cutters.  You can literally see the fibers exposed underneath and yet, it powers up and functions like nothing happened.  I don’t recommend doing any of this, but the point is that it can, and without any adverse effects like fire and explosion.  I can’t rightly tell you what the technology under the hood is – this is the first time we’ve seen this technology in a product and I imagine they want to keep that a secret, but you can’t deny that it is very, very impressive.  

The technology aside for a moment, the S2 has a 5,000 mAh battery, capable of recharging most flagship phones completely from zero to full on a single charge.  It charges via a USB-C port on the rear of the case, capable of pulling 5V⎓3A/9V⎓2.2A to charge itself. It can then push 20W via that USB-C port to an external device with the included cable.  It can also charge a device via the MagSafe connection, even through a case, which is likely the reason you might buy an S2. It also has a special low-power mode they call “Small Current Charging”, accessible by double clicking the power button.  This is for low-power devices like MagSafe smart watches, earbuds, and other low-voltage items, charging at roughly 5W.  Because they are low power, other chargers think they aren’t charging and often shut down, or worse, overcharge them – this prevents that, providing that trickle charge. It’s a nice surprise, and one that might save the batteries on your smaller devices.

In practice, the S2 is Qi2 certified, meaning it charges devices like my Google Pixel 8 Pro wirelessly at 15W – something I can confirm it did the second the magnet connected with the back of my case.  It also works as a passthrough, capable of MagSafe charging while also being itself charged via USB-C.  As a bonus, you can charge off the MagSafe and also charge a second device via that same USB-C. The device is very flexible, and it’s great when technology just works as designed.

The S2 is 5.04oz and measures 4.17” x 2.74” x 0.39”.  It matches the look and feel of my Pixel 8 Pro, as it’s slightly smaller on three sides, and stays roughly a half inch below the camera to ensure unobstructed operation.  A small set of four LEDs on the bottom edge indicate how much charge remains, with a special flash to indicates the aforementioned low-power charge mode.  Connected, it doesn’t overbalance the device, allowing it to rest on its back without tipping forward.  Yes, it does add a bit of weight to the overall package, but it’s stable. 

Back under the hood, the Kuxiu team claims the S2 can go over 1,000 charge / discharge cycles while maintaining more than 80% capacity.  This is in stark contrast to Lithium Ion batteries that can only handle roughly 400 cycles before they start losing capacity – provided they don’t swell anyway.  That’s a long-term value that is easy to see. 

Our last stop on any review is always the same – warranty and price.  The S2 has a 12 month battery, like any other battery on the market. As for price, at the time of writing, the Kuxiu S2 will set you back $47.01 (Amazon link), and is available in either white or black. That puts it a whopping 2 dollars more expensive than an Anker Lithium Ion battery with the same capacity.  Now that you know that this battery is built to last nearly three times longer, charges just as fast (if not faster!) and has a 0% chance of exploding, it’d be irresponsible of me to recommend anything else.  It may not have a fancy name, but the S2 Magnetic Solid-State Power Bank is the next step in battery evolution.