Finding yourself far from a wall socket when your phone hits five percent is positively nervewracking. If you stash a portable battery in your bag, you can avoid that feeling altogether. But there are thousands of power banks out there and it can be tough to pick the right one for what you need. I’ve spent a few years testing dozens of batteries and found the best power banks for different scenarios. Whether you need a quick reup for your phone or a huge brick to keep your laptop alive, you’ll find something fitting here.
Best power banks for 2026
Photo by Amy Skorheim / Engadget
Capacity: 10,000mAh | Maximum Output: 15W (wireless) | Ports: One USB-C in/out | Included cable: USB-C to USB-C | Number of charges iPhone 15: 1.64 | Charge time iPhone: 4 to 100% in 2h 26m and 0 to 70% in 1h 8m | Weight: 8.82 oz | Dimensions: 4.22 x 2.71 x 0.78 in
Anker’s MagGo Power Bank was one of the first Qi2-certified products to come on the market, and the new standard has made the brand’s popular MagSafe/kickstand model much faster. It’s the most well-rounded best MagSafe battery I’ve tested, but if you’re looking for other options, we have an entire MagSafe power bank guide to peruse.
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It brought an iPhone 15 from near-dead to half-full in about 45 minutes. For reference, it took our former top pick in this category an hour and a half to do the same. It’s similarly faster than Anker’s previous generation of this model, the 633, as well. After that initial refill, the MagGo 10K had enough left over to get the phone up to 70 percent on a subsequent charge.
In addition to faster charging speeds, this wireless power bank adds a LCD display to indicate the battery percentage left in the bank, plus the approximate amount of time before it’s full (when it’s refilling) or empty (when it’s doing the charging). A strong MagSafe connection makes it easy to use the phone while it charges and the small kickstand creates a surprisingly sturdy base for watching videos and the like. If you twist the phone to landscape, StandBy mode kicks in.
The power bank did a fine job of charging our Galaxy S23 Ultra — though that model doesn’t have Qi2 support. New Pixel 10 phones do, so those handsets will charge at a faster rate with this battery — and benefit from zero-effort magnetic alignment. The MagGo also has a USB-C port, so if you need to fill up something without wireless capabilities, you can.
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Pros
Qi2 tech enables extra fast wireless charging
Sturdy kickstand props up iPhones as it charges
LED display for battery percentage
Cons
More expensive than other MagSafe packs
Photo by Amy Skorheim / Engadget
Capacity: 5,000 mAh | Maximum Output: 22.5W | Ports: One USB-C and one USB-C connector | Cable: USB-C to USB-C | Number of charges Galaxy S23 Ultra: 0.65 | Charge time: 0 to 65% in 1h 2m | Weight: 3.5 oz | Dimensions: 3.03 x 1.45 x 0.98 in
The Anker Nano power bank has impressive power delivery for its size. It’s the exact size and shape of the lipstick case my grandma used to carry and has a built-in USB-C connector that folds down when you’re not using it. That means that, in addition to being ultra-portable, you don’t need to remember to grab a charging cable when you toss it in your bag. There’s also a built-in USB-C port that can refill the battery or be used to fill up a different device with an adapter cable. Four indicator lights let you know how much charge remains in the battery.
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In my testing, the 5,000mAh battery provided enough charge to get a depleted Galaxy S23 Ultra back up to 65 percent in about an hour. That’s relatively quick, but the Nano is also small enough that, with its sturdy connection, you can use your phone while it’s charging without feeling too awkward. The charger’s small size also makes it a good pick for recharging earbuds.
For a little more juice and an equally clever design, Anker’s 30W Nano Power Bank is a good option for delivering a single charge. It’s bigger in size and capacity (10,000mAh) and includes a display indicating the remaining charge percentage. The built-in USB-C cable doubles as a carry handle, which is a nice touch. That cable is in/out and there’s another USB-C in-out port in addition to an out-only USB-A port.
Cons
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Small enough to get misplaced
Photo by Amy Skorheim / Engadget
Capacity: 10,000mAh | Maximum Output: 30W | Ports: One USB-C in/out port, one USB-C in/out cable, wall prongs | Cable: Built-in USB-C | Number of charges iPhone 15: 1.86 | Charge time iPhone: 5 to 100% 1h 53m and 5 to 91% 1h 5m | Number of charges Galaxy S23 Ultra: 1.45 | Charge time Galaxy: 5 to 100% 1h 2m, 5% to 50% 23m | Weight: 8.8 oz | Dimensions: 4.25 x 2.0 x 1.22 in
The toughest thing about using a power bank is remembering to bring it along. You also have to remember a cable and, if you want to refill the bank itself, a wall adapter. Anker’s 10K Fusion solves two of those problems with its attached USB-C cable for your gadget and foldable two-prong plug for charging the bank itself (yes, you still have to remember to bring the thing with you).
Despite the attachments, it’s compact, just a smidge wider than a stick of butter, yet still packs a 10,000 mAh capacity. The 30 watts of power enabled the “Super Fast Charging” message on a Galaxy S23 android phone and got it from five percent to full in just over an hour. In just 20 minutes, the 10K Fusion bumped a near-dead iPhone 15 to 45 percent. Though it slowed down towards the end of the Apple handset’s charge.
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There’s an additional USB-C port for charging devices that may require a different cable and both it and the built-in connector can be used to refill the power bank. The cable makes a neat loop that looks a lot like a handle. Even though I’m wary of carrying a device around by its cord, it felt sturdy enough.
The onboard display indicates the Fusion’s remaining charge in terms of a percentage and was one of the more accurate readouts I’ve tested. I also like the corduroy texture along the sides — very fidget-worthy.
Our previous pick in this low-capacity category, the BioLite Charge 40 PD, is still an excellent choice — it’s durable, delivers a quick charge and looks cool. I use it often myself. Plus BioLite has an admirable mission of bringing energy to places where it’s otherwise scarce. But Anker’s new release, the 10K Fusion simply delivers a faster charge and more features at a lower price.
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Pros
Has a built-in USB-C cable
Also has built-in wall prongs
Display is fairly accurate
Affordable
Cons
iPhone charging is slower than other banks in its range
Amy Skorheim for Engadget
Capacity: 20,000mAh | Maximumoutput: 30W | Ports: One built-in USB-C in/out cable, one USB-A port, one USB-C port | Cable: USB-C | Number of charges iPhone 15: 3 – 3.5 | Charge time iPhone: 5 to 100% in 2h 6m | Number of charges Galaxy S23 Ultra: 2.5 – 3 | Charge time S23 Ultra: 1h 15m | Weight: 14 oz | Dimensions: 6.06 x 3.0 x 0.99 in
An integrated cable seems to be the hot new feature in portable chargers — and I’m all for it. I can remember times when I’ve had a dead phone and power bank, but no way to connect the two. The Belkin Boost Charge 20K with Integrated Cable is one such bank I’ve tested and also one of the more affordable examples.
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It can output a maximum of 30 watts, which doesn’t make it the fastest charger around, but it wasn’t a slouch. It charged a Samsung Galaxy S24 Ultra from near-dead to full in an hour and 15 minutes and bumped an iPhone 15 from five to 87 percent in just over an hour. And the 20,000mAh capacity means it can achieve those numbers around three times over.
In addition to the built-in (and conveniently magnetized) USB-C cable, there are two other ports: an out-only USB-A and an in/out Type C. That means you can technically charge three devices at the same time, but just note that the amount of charge and the time it takes for things to refill will both take a hit.
There’s no digital screen to tell you how much charge remains in the battery, just four indicator LEDs. I’ve certainly found display readouts to be helpful in determining just how much more juice I can squeeze out of a battery, but the lighted pips here are accurate and still useful.
While color options probably won’t make or break your battery pack purchase, I appreciate that the BoostCharge 20K comes in something other than standard black. You can of course get it in that shade, but also in blue, pink or white. The pink of my tester unit was pale and pretty and the matte finish does a good job of staying clean — some black smudges from who-knows-what in my bag came off easily with some rubbing alcohol.
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Pros
Built-in USB-C cable is handy
Comes in four color options
Affordable
Great capacity for the price
Cons
Charge isn’t as fast as other banks
Photo by Amy Skorheim / Engadget
Capacity: 20,000mAh | Maximum Output: 65W | Ports: Two USB-C in/out | Cable: USB-C to USB-C | Number of charges iPhone 11: 2.95 | Charge time iPhone: 5 to 100% in 1h 39m average | Number of charges Galaxy S22 Ultra: 2.99 | Charge time Galaxy: 5 to 100% in 59m average | Number of charges iPad Air: 1.83 | Charge time iPad: 5 to 100% in 1h 55m and 83% in 1h 21m | Weight: 12.9 oz | Dimensions: 5.92 x 2.48 x 1.00 in
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Nimble’s Champ Pro battery delivers a screaming fast charge and got a Galaxy S23 Ultra from five percent to full in under an hour. That’s faster than every other battery I tested except for Anker’s Laptop Power Bank, our premium pick — and that model costs $30 more. It lent nearly three full charges to both an iPhone and Galaxy device and has enough juice to refill an iPad more than once. The battery pack itself also re-ups from the wall noticeably faster than other models, so it’ll get you out the door quicker.
The company, Nimble, is a certified B-Corp, meaning they aim for higher environmental and social standards and verify their efforts through independent testing. The Champ Pro uses 90 percent post-consumer plastic and comes in packaging made from paper scrap with a bag for shipping back your old battery (or other tech) for recycling.
The unit itself feels sturdy and has a compact shape that’s a little narrower than a smartphone and about as long. The attached adjustable lanyard is cute, if a little superfluous, and the marbled effect from the recycled plastics give it a nice aesthetic. You can charge devices from both USB-C ports simultaneously, and both are input/output plugs.
My only qualm was with the four indicator lights. On a second testing round, it dropped down to just one remaining pip, yet went on to deliver a full fill-up plus an additional top off after that. That said, I’m glad the indicator lights under-estimated the remaining charge rather than the other way around, and the accuracy seemed to improve after subsequent depletions and refills.
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Pros
Super fast charging
Made from recycled materials
Sturdy and compact design
Cons
Indicator lights underestimate charge
Amy Skorheim for Engadget
Capacity: 25,000mAh | Maximum total output: 120W | Ports: Wireless pad (15W), two USB-C (100W), one USB-A (15W), one USB-C (15W) | Cable: USB-C to USB-C (100W) | Number of charges iPhone 15: 5 | Charge time iPhone: 5 to 100% in 1h 52m (wired) 2h 38m (wireless) | Number of charges Galaxy S23 Ultra: 4 | Charge time S23 Ultra: 1h 4m | Number of charges iPad Air: 2.2 | Charge time iPad: 5 to 100% in 2h 20m | Number of charges MacBook Pro: 0.75 | Charge time MacBook Pro: 57 m | Weight: 1.28 lbs | Dimensions: 5.5 x 4.4 x 1.38 in
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The compact and rounded design of the Biolite Charge 100 Max makes it more packable and conducive to travel than the Lion Eclipse Mag. It was also a touch faster in refilling most devices, but since the Charge 100W is $50 more expensive for slightly less capacity, it earns runner-up status.
In addition to four USB ports (three Type-C and one Type-A) It has a MagSafe-compatible wireless charging pad on one side, with a maximum output of 15 watts. The magnetic hold is enough to keep it in place as it charges, but it’s not as strong as you’ll find on smaller MagSafe batteries — I wouldn’t carry it around during a refill.
The 10 LED pips indicate the remaining charge and I found those to be pretty accurate, though the last pip doesn’t flash before it dies like other batteries. The rubberized texture and yellow accents are a welcome aesthetic change from the techy black look of most larger batteries — and it’s quite nice to hold. There’s also plenty to appreciate about the company itself: a climate neutral-certified B-Corporation that helps bring lights and cook stoves to energy impoverished areas around the world.
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Pros
Compact and colorful design
Delivers a quick charge to phones, tablets and laptops
Company is a climate neutral-certified
Cons
More expensive than similar-capacity batteries
Amy Skorheim for Engadget
Capacity: 25,000mAh | Maximumoutput: 165W | Ports: Two built-in USB-C in/out cables, one USB-A port, one USB-C port | Cable: USB-C to USB-C | Number of charges iPhone 15: 4 – 5 | Charge time iPhone: 5 to 100% in 1h 54m | Number of charges Galaxy S23 Ultra: 3.75 – 4 | Charge time S23 Ultra: 52m | Number of charges iPad Air: 1.75 – 2 | Charge time iPad: 5 to 100% in 1h 58m | Number of charges MacBook Pro: 0.68 | Charge time MacBook Pro: 53 m | Weight: 1.31 lbs | Dimensions: 6.18 x 2.12 x 1.93 in
The only thing worse than needing a power bank and not having one is having one but no way to connect it to your device. The Anker laptop power bank with built-in cable forgoes any clever naming scheme, but makes sure you’re never left without a way to charge your stuff.
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It has two attached USB-C cables: one attached to the side of the battery that acts as a carrying cable and another retractable cord that extends up to two feet. Both handle in/out functions so you can use them to refill a device or reup the battery itself.
The display tells you the amount of charge remaining in the battery pack as well as the output wattage that’s funneling towards your devices from each port. When refilling the battery, you can see an estimate of how long it will be until the unit is full. Calculating and displaying info like that takes up a bit of power but, in my testing, the unit outputs the same or a higher amount of charge compared with other 25,000 mAh batteries.
It’s an attractive, high-capacity bank, with matte silver exterior and a smaller display area than Anker’s Prime bank (our previous pick for this category). One of my concerns with that battery was the huge display area which was easily scratched. This newer unit feels more durable.
Two built-in USB-C cables so you’re never without a cord
Durable build
Display shows detailed charging information
Delivers a fast charge
Cons
Screen picks up smudges easily
Anker
Capacity: 26,250mAh | Maximum combined output: 300W | Ports: Two USB-C (140W), one USB-A (22.5W) | Cable: USB-C to USB-C (240W) | Number of charges iPhone 15: 5 – 5.5 | Charge time iPhone: 5 to 100% in 1h 41m | Number of charges Galaxy S23 Ultra: 4.3 | Charge time S23 Ultra: 1h 9m | Number of charges iPad Air: 2.5 | Charge time iPad: 5 to 100% in 1h 50m | Number of charges MacBook Pro: 0.83 | Charge time MacBook Pro: 1h 12m | Weight: 1.32 lbs | Dimensions: 6.3 x 1.5 x 2.5 in
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I knew it wouldn’t be long before I came across an app-connected power bank — the portable battery landscape is crowded and brands are no doubt looking for ways to stand out. Anker’s latest Prime Power Bank (26K, 300W) does stand out, but it’s not because of the app. Yes, it works, letting you see the remaining charge, how much power is going to a device and other bits of data on your phone. But I can’t imagine this info being important to most people. If it is, the same numbers are available on its built-in display anyway.
What’s actually impressive are the speeds the bank delivers, the large capacity and the extra simple recharging via the optional base. The three ports can be used all at once, with the two USB-C ports delivering up to 140 watts each. It’s tough to think of a scenario where that actually happens, as most devices recharge far below that wattage, but if you ever need to partially charge two high powered laptops at the same time, you can.
More commonly, the battery will simply give phones, tablets and laptops speedy refills. It got a near-dead iPhone 15 to 60 percent in a half hour and delivered more charge to my MacBook Pro than any other battery I’ve tested. The display not only tells you how much charge is left in the battery, it also has a temperature gauge — a wise thing to keep an eye on when it comes to lithium ion batteries.
The attractive and sleek design has a shiny black front where the display lives and a matte silver body. The bank is more compact than most 27,000mAh batteries out there. Anker made the battery a little wider and flatter than the last round of Prime devices, which makes it a bit easier to handle and somehow looks more elegant than the square brick did.
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The charging power base is a separate (and optional) purchase, but it makes recharging the battery extra convenient — you just plunk it down and walk away. It’s the same base used with the previous line of Anker Prime batteries, so if you have one already, you’re set. Unfortunately the base costs $110. Combined with the battery, that’s more than $300, but if you want a truly premium power bank, this is it.
Pros
Delivers a super fast charge
Sleek and premium design
Display shows remaining charge and battery temperature
Cons
Pricey, especially with the optional base
Photo by Amy Skorheim / Engadget
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Capacity: 15,000mAh | Maximum Output: 32W | Ports: One USB-C in/out, one USB-C in, one USB-A | Cable: USB-A to USB-C | Number of charges iPhone 11: 2.99 | Charge time iPhone 11: 0 to 100% 2h average and 0 to 99% in 1h 45m | Number of charges iPad Air: 1.17 | Charge time iPad: 0 to 100% 2h 23m and 0 to 17% 15m | Weight: 12.8 oz | Dimensions: 5.0 x 1.25 x 3.0 in
Plenty of battery packs are built to withstand drops and other abuse, but very few are waterproof or even water resistance. It makes sense; water and electrical charges aren’t good companions. The Nestout Portable Charger battery has an IP67 rating, which means it can handle being submerged in water for a number of minutes, and Nestout claims a 30-minute dunk in a meter of water shouldn’t interfere with the battery’s operation. I couldn’t think of a likely scenario where a power bank would spend a half hour in three feet of water, but I could see a backpacker traversing a river and submerging their pack for a few minutes, or a sudden downpour drenching all of their gear. So I tested by dropping the battery in a five gallon bucket of water for five minutes. After drying it off, the unit performed as if it had never been wet.
The water resistance comes courtesy of screw-on caps with silicone gaskets that physically keep the water out, so you’ll need to make sure you tighten (but don’t over tighten) the caps whenever you think wetness is in your future. The company also claims the battery lives up to a military-standard shock/drop specification which sounds impressive, but it’s hard to pin down what exactly that means. I figured it should at minimum survive repeated drops from chest height onto a hard surface, and it did.
As for charging speeds, it wasn’t quite as quick as our recommendation for a mid-capacity bank. The Belkin charged an iPhone 15 to 80 percent in under an hour and the Nestout got the smaller iPhone 11 to 80 percent in a little more than that. Another thing to note is that the supplied cable is short, just seven inches total, so you’ll likely want to use your own cord.
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Nestout also makes accessories for its batteries, which I found delightful. A dimmable LED worklight snaps on to the top of the battery while a small tripod holds them both up. The portable solar panel reminded me of a baby version of Biolite’s camping panels. Nestout’s version refilled the 15,000mAh bank to 40 percent in under three hours, which sounds slow, but is actually fairly impressive considering the compact size of the panels. This is also a blazingly hot summer, so I’d expect better performance in more reasonable weather.
Pros
Waterproof with the caps secured
Clever accessories (sold separately)
Survived drop tests
Cons
Not the fastest charge times
Included cable is short
What to look for in a portable battery pack
Battery type
Nearly every rechargeable power bank you can buy (and most portable devices) contain a lithium-ion battery. These beat other current battery types in terms of size-to-charge capacity, and have even increased in energy density by eight fold in the past 14 years. They also don’t suffer from a memory effect (where a battery’s lifespan deteriorates due to partial charges).
Flying with portable batteries
You may have heard about lithium ion batteries overheating and catching fire — a recent Hong Kong flight was grounded after just such a thing happened in an overhead bin. Current restrictions implemented by the TSA still allow external batteries rated at 100Wh or less (which all of our recommendations are) to fly with you, but only in your carry-on luggage — they can’t be checked.
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Recently, Southwest Airlines was the first in the industry to take that rule one step further. Now, flyers on that airline must keep power banks in clear view when using them to recharge a device. If the portable charger isn’t actively in use, however, it can stay in your carry-on bag in the overhead bin.
Capacity
Power bank manufacturers almost always list a battery’s capacity in milliamp hours, or mAh. Smaller batteries with a 5,000mAh capacity make good phone chargers and can fill a smartphone to between 50 and 75 percent. Larger batteries that can recharge laptops and tablets, or give phones multiple charges, can exceed 25,000mAh and we have a separate guide that covers that entire category.
Unsurprisingly, the prices on most batteries goes up as mAh capacity increases, and since batteries are physical storage units, size and weight go up with capacity as well. If you want more power, be prepared to spend more and carry around a heavier brick.
You might think that a 10,000mAh power bank could charge a 5,000mAh phone to 100 percent twice, but that’s not the case. In addition to simple energy loss through heat dissipation, factors like voltage conversion also bring down the amount of juice that makes it into your phone. Most manufacturers list how many charges a battery can give a certain smartphone. In our tests, 10,000mAh of battery pack capacity translated to roughly 5,800mAh of device charge. 20,000mAh chargers delivered around 11,250mAh to a device, and 25,000mAh banks translated to about 16,200mAh of charge. That’s an average efficiency rate of around 60 percent.
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Wireless
Wireless charging, whether through a bank or a plugged-in charging pad, is less efficient than wired connections. But it is convenient — and in most cases, you can carry around and use your phone as it refills with a magnetically attached power bank.
Power banks with wireless charging are far better than they once were. Just a couple years ago, the ones I tested were too inefficient to recommend in this guide. When batteries adhering to the Qi2 wireless charging standard started arriving in 2023, performance markedly improved.
To gain Qi2-certification, a device has to support speeds of up to 15 watts and include magnetic attachment points. The MagSafe technology on iPhones were once the only handsets that were Qi2-compatible, but now Google’s Pixelsnap tech brings both the higher speed and magnetic grip to Pixel 10 phones. Samsung may follow up with its own version in future releases.
The latest wireless charging standard, Q12 25W, is supported by the new iPhone 17 phones as well as the Google Pixel 10 Pro XL. Battery packs that are Qi2 25W-enabled are starting to hit the market as well, and the Ugreen MagFlow was the first on the scene.
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Ports
USB-C ports can deliver faster charges than USB-A ports, and most of the portable chargers we recommend here have Type-C connections. But Type-A jacks are still handy if you need to use a specialized cable for a certain device (my camera’s USB-A to micro USB cable comes to mind).
There’s also variation among USB-C ports. Larger banks with more than one port will sometimes list different wattages for each. For example, a bank with three ports may have two 65W ports and one 100W port. There will also be at least one in/out port on the bank, which can be used to charge the battery itself or to deliver a charge to your device. Wattages and in/out labels are printed right next to the port — and always in the tiniest font possible (remember, your phone is an excellent magnifying glass if you ever have trouble reading them).
As with standard wall chargers, the port’s wattage will determine what you can charge. A phone will happily charge off a 100W connection, but a 15W plug won’t do much for your laptop. And remember, the cable has to match the maximum wattage. A cable rated for 60W won’t deliver 100W speeds.
Luckily, some of the best power banks include a built-in USB-C cable. That’ll not only ensure you have the right cord, it’s one less thing you have to remember to bring along.
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Design
Once, most rechargeable batteries were black with a squared-off, brick-like design, but now they come in different colors and shapes with attractive finishes and detailing. While that doesn’t affect how they perform, it’s a consideration for something you’ll interact with regularly. Some portable power banks include extra features like MagSafe compatibility, a built-in wall plug or even a kickstand. Nearly all have some sort of indicator to let you know how much available charge your power bank has left, usually expressed with lighted pips near the power button. Some of the newer banks take that a step further with an LED display indicating remaining battery percentage.
How we test best power banks
First, I considered brands Engadget reviewers and staff have tried over the years and checked out customer ratings on retail sites like Amazon and Best Buy. Then, I acquired the most promising candidates and tested them in my home office.
Amy Skorheim for Engadget
For testing, I used each battery to charge both an iPhone and an Android phone, as well as an iPad and a MacBook Pro for the larger portable chargers. I let the devices get down to between zero and five percent and charged them until the devices were full or the power bank died.
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For reference, here are the battery capacities of the device I’ve used for testing over the years:
*The iPhone 17 has a slightly larger battery at 3,692mAh
I continuously update this guide as companies release new products.
Other power banks we tested
Here are a few picks that didn’t quite make the cut, but are worth mentioning.
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Belkin Stage PowerGrip
If you’re into iPhonography, this clever accessory could be worth a look. Belkin’s Stage PowerGrip is a 9,300mAh power bank that has both a wireless charging pad and built-in cable. But it’s also a Bluetooth shutter with a quarter-inch tripod thread. The design resembles a standard digital camera and provides a sturdy grip once you magnetically attach your phone (make sure you’re either using a MagSafe case or no case to ensure a solid connection).
The shutter is conveniently placed and the remote speed was quick enough to capture the cute things my cat was doing. The accessory can even act as a stand while it charges in either landscape or portrait orientation. As a power bank, it’s slow, taking about two hours to get my iPhone 16 from three to 98 percent, but it has enough juice for a full refill plus a little more, which could help if you’re out taking pictures all day.
Anker MagGo for Apple Watch power bank
The Anker MagGo for Apple Watch power bank combines a 10K battery with a built-in USB-C cable and a pop-up Apple Watch charger. I didn’t formally test it as it’s a little too niche, but it deserves a mention for saving my keister on two occasions. Driving to a hike, my watch told me it was down to 10 percent. Thankfully, I had this and could refill the watch before I got to the trailhead. Later, on an interstate trip, I realized the travel charging station I’d brought was a dud. This kept my watch alive for the week I was away. It does a good job simply charging a phone via the handy on-board cable, too. But for those with an Apple Watch, it’s extra useful.
HyperJuice 245W
Hyper’s massive-but-sleek brick is one nice looking power bank. The HyperJuice 245W packs a hefty 27,000mAh capacity, enough to refill my tester phone about four times and get a MacBook Pro from near-dead to 75 percent. It only has USB-C ports, but you at least get four of them. USB-C only is probably fine for most situations, but a USB-A port would be nice for charging the occasional older peripheral. The 245 wattage is pretty high for a power bank and it was indeed speedy. It filled a Samsung Galaxy S24 Ultra in just over an hour. But it’s the same price and capacity as our Mophie Powerstation pick for laptop banks, and that one has a better variety of ports. Hyper’s battery is also comparable to Anker’s laptop battery, which is cheaper, has built-in cables and has nearly the same capacity. Plus, that bank is just as swanky looking.
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EcoFlow Rapid magnetic power bank
I was curious to try out the first power bank from EcoFlow, a company that primarily makes larger power stations and whole-home backup batteries. The first offering in the brand’s Rapid series is a Qi2-enabled magnetic charger with a 5,000mAh capacity. It looks quite nice with shiny silver accents and soft-touch grey plastic on the MagSafe-compatible front. There’s a little pull-out leg that sturdily displays your phone as it charges and the attached USB-C cable lets you refill devices directly, then tucks out of the way when it’s not in use. But it didn’t outperform our top pick in the MagSafe category, in terms of both charging speeds and the amount of charge delivered.
Mophie Snap+ Powerstation Mini
The Mophie snap+ Powerstation Mini is terribly well-built. It feels premium with a rubberized contact point for the MagSafe charging pad and a stand that runs the entire width of the bank itself, making it extra sturdy. It’s compact, too, but only carries a 5,000mAh capacity, which gets you a partial charge on most newer or larger phones. Our current MagSafe/iPhone pick has double the capacity, a stand and a digital display — for just $20 more than the Powerstation Mini.
Power bank FAQs
What’s the difference between a portable power bank and a portable charger?
A slew of terms are used to describe power banks, including portable batteries, portable chargers, external battery packs and even, somewhat confusingly, USB chargers, which is what wall chargers are often called. They all mean the same thing: a lithium ion battery that stores a charge so you can refill a smartphone, tablet, earbuds, console controller, ereader, laptop, or just about any other device with its own built-in, rechargeable battery.
There’s little difference between the terms, so the specs you’ll want to pay attention to are capacity (expressed in mAh), size and weight so you can find the right balance between recharging what you need and portability.
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Power stations, on the other hand, are distinct. These are bigger units (often around the size of a car battery) that can be used to charge multiple devices multiple times, but notably, they can’t be taken on airplanes.
Does fast charging actually ruin your battery?
Not exactly. The real enemy of a battery’s longevity is heat. The faster you charge a battery, the more heat is generated. Modern phones have features that keep the battery cool while charging, like physical heat shields and heat sinks, as well as software features that slow down processes that generate too much heat. Phone manufacturers are keen to promote a phone’s fast-charging abilities, so they had to figure out ways to make faster charging work.
While there aren’t long-term studies on what fast charging does to a phone, a study on EV batteries (which use the same general concept of charged lithium ions flowing from one side of the battery to the other, absorbing or releasing a usable charge) showed a very slight decrease in capacity over time with only fast charging — though what actually made a larger difference was how hot the battery itself was, due to ambient temperatures, when it was charged.
In short, fast charging could be slightly harder on your battery than normal charging. But the safeguards most smartphones have make that difference fairly negligible. To really ensure you’re optimizing charging capabilities, limit your phone’s heat exposure overall.
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Can you use a power bank for all your devices?
That depends on the size of the bank and the size of your device’s battery. A small 5,000mAh battery isn’t strong enough to charge laptops, but a portable charger with a 20,000mAh capacity will give your computer a partial refill. You also have to consider port compatibility. If your device has a USB port, you’ll be able to easily find a cable to connect it to a battery. If your device has a more unique port, such as a DC port, you won’t be able to use a battery. Devices with an AC cable and plug can be charged, and sometimes powered (such as in the case of a printer or speaker), by larger laptop batteries with AC ports.
An events company whose associates helped stage the January 6, 2021 rally has signed contracts worth over $26 million with the United States government, according to documents reviewed by WIRED. Since President Donald Trump’s return to the White House, Event Strategies, a Virginia-based firm with deep ties to Trumpworld, has negotiated a contract with the General Services Administration that could be worth up to $100 million over the next 15 years.
It’s a remarkable rise for the 26-year-old firm, which until the recent windfall had received what appeared to be around $50,000 dollars in government contracts over the past decade. It also appears that Event Strategies won these new contracts with very little competition. According to HigherGov, a tool used by contractors to track federal and state contracts, Event Strategies was the only company to bid on eight of the 11 contracts tracked by the site.
Many of the recent contracts are related to America 250, an 18-month-long commemoration of the 250th anniversary of the signing of the Declaration of Independence.
In early 2025, the US Semiquincentennial Commission, a bipartisan group established in 2016 to coordinate the celebrations, cut ties with Precision Strategies, an event planning group founded by Obama-era staffers. Soon after, the commission hired Event Strategies to replace them.
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Contracts reviewed by WIRED in the System for Award Management database show that by September 2025, the company had signed its first contract related to the celebrations: a $5 million contract for work related to Titans of the Sea, an event designed to celebrate the Navy’s 250th anniversary. Weeks later, the company signed another contract for a $2.1 million deal for “AMERICA 250 – EVENTS.”
More recently, Event Strategies signed a contract valued at $333,084 with the General Services Administration at the beginning of February for “FREEDOM 250 DESIGN AND CONTENT SUPPORT SERVICES.” Freedom 250 is, according to the White House, a “public-private partnership” related to America 250.
The tenor of the America 250 celebrations have already proven controversial. Over the last few months, large banners ostensibly tied to the project were seen hanging from federal buildings all over Washington, DC. One banner, which was hung outside the Department of Justice, features the tagline: “Make America Safe Again” alongside a massive image of Trump’s face. The DOJ said the banner was hung to “celebrate 250 years of our great country.” To many, the tagline was an indication that the Justice Department has failed to maintain its independence during Trump’s second term. California Governor Gavin Newsom said the banner was “beyond parody,” writing on Facebook: “How many dictatorship-style monuments, building name changes, and fake awards do Americans have to endure?”
In early March, banners featuring Charlie Kirk, Booker T. Washington, and Catharine Beecher were hung outside the Department of Education near Capitol Hill, alongside two large banners featuring the America 250 logo. Critics were alarmed to see Kirk’s likeness on the banner, as the deceased Turning Point USA cofounder and conservative commentator had previously called to “abolish” the Department of Education and was known for numerous racist and homophobic comments.
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WIRED could not confirm whether these specific banners, or the banners hanging at the DOJ, were designed and implemented by Event Strategies. The DOJ and the Education Department did not respond to a request for comment about the company responsible for the banners.
“There is a proper federal competitive bidding process, and the White House expects all agencies to comply with it,” White House spokesman Davis Ingle tells WIRED. When asked for further comment about Event Strategies, Ingle referred WIRED to the General Service Administration. GSA did not respond to a request for comment.
The Contracts
When Trump lost the 2020 election, Event Strategies was on hand: Cofounder Tim Unes was listed as a stage manager for the January 6 rally at the Ellipse in 2021, according to the paperwork submitted to secure a permit. Megan Powers Small, who is now the chief of staff at Event Strategies, was tagged on rally permit paperwork as the event’s “Operations Manager for Scheduling and Guidance.” Justin Caporale was listed as a project manager of the event. Though Caporale was later described as the Event Strategies CEO and the company’s managing partner, he had previously worked as director of operations for Melania Trump in 2018 and on the Trump campaign in 2020.
While out of office, Trump continued working with Event Strategies. The company produced many of Trump’s campaign rallies during the 2024 presidential campaign; filings from that year show Event Strategies received $31 million from the Trump 47 Committee PAC over a seven-month period. Caporale’s Instagram account also shows him associating with Trump and administration officials, including at some of those same rallies.
GeekWire co-founder John Cook, left, with Korell, his hair stylist at Amazon Salon in London. (GeekWire Photo)
Strolling among the food vendors and independent pop-up shops of London’s historic Spitalfields Market, I stumbled upon a modern slice of American retail.
There, just a stone’s throw from merchants selling Mick Jagger portraits and piping hot dumplings, was a curiosity I did not expect: Amazon’s iconic curved arrow logo attached to a retail storefront called Amazon Salon.
Really? Amazon was in the hair coloring and neck massage industry?
We all know Amazon as a master of book sales, cloud computing and Prime Video — but I certainly had to determine how a Seattle-based tech juggernaut fared at cutting hair.
Amazon opened its first-ever — and to this day only — hair salon in the east London neighborhood five years ago. At the time, an Amazon executive said it would “bring us one step closer to customers, and it will be a place where we can collaborate with industry and test new technologies.”
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Frankly, I had completely forgotten about GeekWire’s coverage of Amazon Salon — after all, it was one of many experiments that the so-called “everything store” was rolling out at the time.
I wasn’t really in need of a haircut. But I couldn’t resist this once-in-a-lifetime opportunity to get my locks trimmed by Amazon.
Stepping into a salon operated by a $2.3 trillion company didn’t look or feel much different than a slightly upscale Great Clips. It was clean, well-organized and the staff were overly pleasant — even with a curious American tourist asking a lot of questions.
Amazon Salon stylist Korell goes to work on GeekWire co-founder John Cook’s hair in London. (GeekWire Photo / John Cook)
Luckily, it was a slow Monday afternoon, so the staff were able to accommodate me as a walk-in. I was introduced to Korell, a gregarious stylist with a big laugh who has worked at the shop since its opening.
I informed Korell of the “experiment” I was undertaking, and he was happy to play along with a nice “tidy-up.”
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“I kind of get your vibe,” he told me.
Beyond the “Amazon Salon”-branded barber’s gown and the logo on the wall, there was nothing particularly Amazon-y about the experience.
No robotic scissor cuts, frictionless check-out or AI-generated imagery showing what I’d look like with purple hair.
You are able to purchase beauty products on the wall with ease and have those shipped directly to your residence via Amazon, of course.
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One thing Amazon Salon absolutely nails, however, is the haircut itself. Korell spent more than an hour sculpting, crafting, washing and styling my hair in a way I’ve never experienced.
(GeekWire staffers know I am not really a salon kind of guy. I previously took advantage of a promotion at Great Clips that allowed for free haircuts if the Seattle Sounders scored three goals in a game. Frustratingly, this promotion no longer exists.)
GeekWire’s John Cook before his haircut, left, and after at Amazon Salon in London. (GeekWire Photos)
You can judge for yourself, but I’ve never had a better trim (or salon experience). I joked with Korell that I’d look pretty darn good for that night’s football match at London Stadium. (West Ham United knocked off Brentford in penalties to advance in the FA Cup.) No wonder Korell told me that they’ve experienced a steady stream of business over the years, with a number of repeat customers.
Upon check-out, I wondered if I’d be able to somehow link to an Amazon account for payment or perhaps “just walk out” — but neither service was available. I was told that the salon discontinued the Amazon account tie-in functionality, in part because they were drawing a number of out-of-country customers (like me) and they needed an Amazon UK account. It was just easier to pay, like any other salon.
A few hours after the $60 haircut I received an auto-generated email: “It was great to see you at Amazon Salon today, we hope you love your new hair!”
Apple’s MacBook lines will not be badly affected by the extreme memory, processor, and SSD price increases, that are forcing the rest of the industry to hike retail prices more than 40%.
A Samsung LPDDR5X memory chip – Image Credit: Samsung
The tech industry is currently being squeezed by demand for chips used for memory and SSD storage. It’s a situation worsened by shortages in CPU supplies, which will only apply more pressure on manufacturers to charge consumers more. While most of the computer manufacturing industry will be affected, Apple’s supply chain has insulated itself enough that it won’t be an issue. Continue Reading on AppleInsider | Discuss on our Forums
Ford’s 7.3-liter “Godzilla” V8 earned a lot of attention when it debuted under the hood of F-Series Super Duty trucks for the 2020 model year. It wasn’t just from heavy-duty pickup truck buyers, either, but also from fans of the American V8 engine in general — and rightfully so. The Godzilla’s 430 hp and 485 lb-ft of torque are impressive figures, but that was just part of the story. What really makes the Godzilla special is the way it stands out from other modern V8s on the market.
Despite being an all-new engine design from Ford, the Godzilla forgoes modern tech like overhead cams and forced induction. Instead, it’s a classic pushrod V8 that delivers its power with old-school, big-displacement simplicity. But how does this brute of an engine stack up against other modern V8s in terms of output? We’ve rounded up five different V8s that outdo that mighty Godzilla when it comes to horsepower — albeit with some significant asterisks when it comes to both price and purpose.
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For this grouping, we’ve limited our selections to naturally aspirated gasoline V8s currently available in new vehicles, excluding V8s with superchargers or turbochargers, as well as turbodiesel engines. While all of these V8s indeed outdo the Godzilla in peak horsepower, many of them are built for entirely different types of vehicles, and comparing their specs truly helps bolster the Godzilla’s reputation as one of the more unique V8 engines of the modern era.
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Ford 5.0 Coyote V8 – 500 hp
One smaller V8 engine that outpowers the Godzilla comes from right within the Ford family. That engine would be the tried-and-true Ford 5.0 V8, often known as the Coyote. Ford currently offers a few different variants of its DOHC 5.0, with the more yeoman F-150 pickup version already making 400 hp. It’s in the modern Mustang, though, where the Coyote leaps ahead of the Godzilla in peak horsepower.
In the standard Mustang GT, the 5.0 makes 480 hp, and that number jumps to 500 hp in the fast and highly-entertaining Mustang Dark Horse. However, being a big-displacement truck motor, the Godzilla’s 485 lb-ft of torque easily outpulls the 418 lb-ft of the smaller, higher-revving 5.0. And as you’d expect from a truck engine, the larger 7.3 makes its peak torque and power at significantly lower revs than the Coyote — 5,000 and 4,400 rpm, respectively, versus the Dark Horse’s 7,250 and 4,900 rpm.
Comparing these two engines is very fascinating. Both are modern, naturally aspirated, mass-produced V8 engines from Ford, but that’s about where their similarities end. In that sense, it’s a lot like the old days when American carmakers offered both high-winding small-block V8s for performance cars and larger, more utilitarian big-block V8s for their heavy-duty trucks.
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Chevrolet Corvette 6.2 V8 – 490 hp
JustPhotos22/Shutterstock
When Ford released the Godzilla engine, the most notable thing about it wasn’t just it’s size, it was the fact that it used the old school, overhead-valve pushrod design, which Ford had moved away from when it began introducing its modular, overhead cam V8s in the 1990s. Chevrolet, on the other hand, has stuck with pushrods and has plenty of V8-powered models in its lineup.
In terms of truck engines, Chevy currently does not have any naturally-aspirated V8s that outpower the Godzilla, though its 6.6-liter V8 HD truck engine puts up a decent fight in both horsepower and torque. And with the Camaro now out of the picture, you need to move over to the Corvette lineup to find a naturally aspirated Chevy V8 that outpowers the Ford 7.3.
The entry-level C8 Corvette Stingray, which is not “entry-level” at all when it comes to performance, is powered by the LT2, a naturally-aspirated 6.2-liter pushrod V8 that makes 490 hp as standard or 495 hp with the performance exhaust option. What about torque? At 470 lb-ft, the Corvette comes close to the Godzilla’s torque output. Since it’s a smaller performance car engine, though, the LT2 only hits that number at 5,150 rpm, a few hundred more revs than the Godzilla.
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Toyota 5.0 V8 – 471 hp
With naturally aspirated V8s going out of favor around the global industry, Toyota is one of the only non-American manufacturers to offer a naturally aspirated V8 of any type, let alone one that outpowers the Ford Godzilla. That engine is the 5.0-liter DOHC 2UR-GSE V8, which ranks among the most powerful engines that Toyota has ever built, V8 or otherwise.
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Offered in the Lexus LC 500 Coupe as well as the IS 500 sedan, which it discontinued in 2025, the 2UR-GSE makes 471 naturally aspirated horsepower. As you’d imagine from a significantly smaller, DOHC engine used in a luxury performance car, the 2UR’s advantage over the Godzilla does not carry over to the torque department. Rated at 398 lb-ft of torque, the Lexus engine is down nearly 100 lb-ft from the workhorse Ford 7.3 — totally expected considering the very different types of vehicles these engines power.
A closer Toyota V8 to the Godzilla, at least in terms of vehicle, would have to be the now-discontinued 5.7-liter from the second-generation Tundra and Sequoia. While Toyota has never offered a true heavy-duty pickup that would need an engine as large as the 7.3-liter Godzilla, the 5.7’s 381 hp and 401 lb-ft were — and still are — impressive numbers for a naturally aspirated V8 of its size.
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Ram/Jeep 6.4 HEMI V8 – 470 hp
Of all the naturally aspirated V8 engines currently on the market, the one that comes closest to the Ford Godzilla in displacement, design, and output might be the 6.4-liter HEMI engine. Although this version of the HEMI isn’t currently available in as many vehicles as it once was, you can still find it under the hood of the Jeep Wrangler 392 and the Ram HD pickup.
In the Ram HD, which competes directly against the Ford Super Duty, the more utilitarian version of the 6.4 HEMI makes 405 hp and 429 lb-ft of torque, both lower than the Godzilla. In the Jeep Wrangler 392, though, the 6.4 HEMI makes a more potent 470 hp and 470 lb of torque, outdoing the Godzilla by 40 horsepower but with 15 lb-ft less torque.
Of course, you can find HEMI V8s that significantly outgun the Godzilla and both horsepower and torque — you’ll just need to add a supercharger and some Hellcat badges to do it. We shouldn’t bring Hellcats into this conversation, though, as Ford has its own supercharged V8s in offerings like the Raptor R and Mustang Dark Horse SC that go head-to-head with the Hellcat. That’s a comparison for a different time.
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Chevy Corvette Z06 5.5 V8 – 670 hp
Dragos Asaftei/Shutterstock
The Chevrolet LT6 V8 from the C8 Corvette Z06 is an engine that, beyond being a naturally aspirated American V8, could not be more different from the Ford Super Duty’s Godzilla 7.3. The Godzilla is a huge, pushrod V8 designed for pickup trucks, while the LT6 is a race-bred DOHC V8 with an exotic flat plate crankshaft designed to take on some of the world’s fastest supercars.
So in the real world, the groundbreaking LT6 powering a mid-engined American supercar should have no business being compared to a workhorse Ford pickup V8. And in terms of power, the LT6 absolutely destroys the Godzilla with its 670 hp, about 240 hp more than the Godzilla. But while the LT6’s 460 lb-ft of torque is absolutely incredible for a naturally aspirated, 5.5-liter engine, the Godzilla’s 485 pound-feet still gives it the win there.
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In fact, the DOHC V8 in the Z06 actually has slightly less torque than the pushrod V8 in the base Corvette C8. Such is the nature of small-displacement, overhead cam V8s compared to larger pushrod engines. And as for comparing the exotic Chevy LT6 to the more blue-collar Ford 7.3, the fact that one can even mention these two engines in the same sentence shows just how strong and varied America’s current V8 offerings are. While there was a time when it seemed widespread engine downsizing could spell the end of the naturally aspirated V8, both the throwback Godzilla and all of these other options show that the V8 is alive and well.
In one case, an AI checker pre-installed on a school-issued Chromebook flagged a student’s essay on Harrison Bergeron by Kurt Vonnegut as “18% AI-written” simply because it contained the word “devoid.” Read Entire Article Source link
At the centre of the system is Intel’s Core i5-13450HX processor, a 13th Gen chip built on the Raptor Lake architecture. It’s paired with 24GB DDR5 memory, which gives the laptop plenty of breathing room when running multiple applications or heavier projects.
Storage comes in the form of a 1TB PCIe SSD, providing fast load times and plenty of space for files, software, and media.
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Graphics are handled by Nvidia’s GeForce RTX 5050 with 8GB GDDR7 memory. That hardware supports modern features like ray tracing and DLSS, helping deliver smoother performance in graphics-heavy applications.
The laptop has a 15.6in IPS display with a Full HD resolution of 1920 x 1080 and a 144Hz refresh rate. The panel also covers 100% of the sRGB colour space. Nvidia G-Sync support helps keep frame pacing consistent.
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Lenovo also includes its AI Engine+ system, which automatically adjusts performance settings by balancing CPU, GPU, and thermal behaviour depending on what you’re doing.
The chassis comes in a Luna Grey finish and weighs around 2.4kg. The build uses aerospace-grade materials, while a white backlit keyboard and full numeric keypad make it practical for both work and play.
There’s also a 5MP webcam with an eShutter privacy switch, so you can physically disable the camera when not in use.
Connectivity includes Wi-Fi 6, Bluetooth 5.1, HDMI, Ethernet, and multiple USB ports for connecting external displays, storage, and accessories.
It takes around 30 hours to experience everything Resident Evil Requiem has to offer. If you’ve already enjoyed all the thrills and spills and you’re itching for more, there’s some positive news. Capcom has some updates on the way. The biggest of those is a story expansion, which is now in development. Just don’t expect it to arrive imminently.
“In this story, we will delve deeper into the world of Requiem,” game director Koshi Nakanishi said in a short video message. “We’re hard at work on it now. It will take some time, so we ask for your patience and hope you’ll look forward to it.”
Nakanishi noted that on top of the story expansion and fixing bugs and performance issues, the development team is cooking up some other features. A photo mode is on the way to help you capture all the horrors that Grace and Leon encounter. There’s also a “surprise coming around May,” Nakanishi said. “We’re planning to add a mini-game.”
With DJI’s Mini 4K now nearly 30% cheaper, it’s suddenly a perfect time to level up your travel shots and weekend adventures.
The DJI Mini 4K drops from £268 to £189 in the Amazon sale, a saving of £79 on a drone that weighs less than a tin of beans but shoots stabilised 4K footage from a three-axis gimbal.
DJI’s Mini 4K is almost 30% cheaper in the latest deal
A fresh deal has made DJI’s Mini 4K almost 30% cheaper, offering a standout saving on a beginner‑friendly drone.
The DJI Mini 4K sits among the most capable lightweight options in a category where the best drones of 2025 have raised the bar considerably for sub-250g flight.
That three-axis gimbal actively compensates for wind and movement to keep footage smooth in conditions where a fixed-mount camera would produce shaky, unusable clips, regardless of how carefully you fly.
The DJI Mini 4K is rated to hold stable flight in Level 5 winds of up to 38kph, with brushless motors maintaining control at altitudes up to 4,000 metres without struggling.
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Its video transmission reaches up to 10km, which is far enough that the limiting factor on any flight will be battery life or local regulations rather than signal quality, and the anti-interference capabilities keep the connection clean even in areas with competing wireless signals nearby.
Intelligent QuickShots handle the complex flight paths that produce cinematic results automatically, with Helix, Dronie, Rocket, Circle, and Boomerang modes each executing a pre-programmed sequence at the tap of a button, so the DJI Mini 4K does the flying while you focus on framing.
Anther good feature is the GPS Return to Home, which brings the drone back to its takeoff point automatically if the signal drops or the battery runs low, and one-tap takeoff and landing removes the manual coordination that puts beginners off their first few flights entirely.
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The single-battery configuration included in this version of the DJI Mini 4K gives a maximum flight time of 31 minutes, and upgrading to the two or three-battery sets extends that to 62 or 93 minutes, respectively.
And If you plan longer sessions, this £189 entry point is a sensible starting place before committing to additional accessories.
That fireball was LZ37. Nobody wanted to see repeats post-war. Image: “The great exploit of lieutenant Warnefort 1916 England” by Gordon Crosby, public domain.
After all the crashing and burning of Imperial Germany’s Zeppelins in the later part of WWI – once the Brits managed to build interceptors that could hit their lofty altitude, and figured out the trick of using incendiary rounds to set off the hydrogen lift gas – there was a certain desire in airship circles to avoid fires. In the USA, that mostly took the form of substituting hydrogen for helium. Sure, it didn’t lift quite as well, but it also didn’t explode.
Still, supplies of helium were– and are– very much limited, and at least on a rigid Zeppelin, the hydrogen wasn’t even the most flammable part. As has become widely known, thanks in large part to the Mythbusters episode about the Hindenburg disaster, the doped cotton skin in use in those days was more flammable than some firestarters you can buy these days.
That’s a problem, because, as came up in the comments of our last airship article, rigid airships beat blimps largely on Rule of Cool. Who invented the blimp? Well, arguably it was Henri Griffard with his steam-driven balloon in 1857, but not many people have ever heard his name. Who invented the rigid airship? You know his name: Ferdinand Adolf Heinrich August Graf von Zeppelin. No relation. Probably. Well, admittedly most people don’t know the full name, but Count Zeppelin is still practically a household name over a century after his death. His invention was just that much cooler.
That unavoidable draw of coolness led to the Detroit Airship Company and their amazing tin blimp. The idea was the brainchild of a man named Ralph Upton, and is startling in its simplicity: why not take the all-metal, monocoque design that was just then being so successfully applied to heavier-than-air flight, and use it to build an airship?
Of course everyone’s initial reaction to the idea is that it’s absurd: metal is too heavy to fly! They said that about airplanes once, too, but airships are surely a different matter. Airships must be lighter than air. Could a skin of aluminum really hold enough lift gas to keep itself in the air? Upton convinced no lesser lights than Henry Ford to back him, and the Detroit Aircraft Company ultimately found a customer for the design in the US Navy.
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Schwartz’s unsuccessful airship, shortly before its crash. Image credit: unknown, public domain.
It helped that Upton wasn’t exactly the first to come up with this idea: David Schwarz had tried to build a metal airship at the end of the 19th century. Arguably it is he who invented the rigid airship, not my aura farming not-ancestor. His design had metal skin over an internal framework, rather than the lighter monocoque construction Upton was exploring. While it was by no means a success, being destroyed on its maiden flight, the fact that it had a maiden flight at all at least proved that metal structures could be made light enough to get off the ground.
The Detroit Airship Company’s first– and only, as it turned out– prototype was much more successful, as we will see. It was immediately nicknamed the “tin blimp” by the press after it was unveiled in 1929, that name was incorrect in every particular. It wasn’t tin, and it wasn’t a blimp. Well, not exactly, anyway. More on that later.
How To Make a Metal Balloon
Compared to the various frames, longitudinal girders, bracing wires and fabric-backed gas bags of a Zeppelin-type airship, the ZMC-2’s balloon was simplicity itself. The balloon–if you can call it that–was a hollow spheroid built up of strips of 0.0095” (0.24 mm) Alclad sheeting. Alclad is a sort of metallic composite material: a sheet of duraluminum coated with a very thin protective layer of pure aluminum to provide corrosion resistance. The ZMC-2 was actually the first major use of Alclad, but hardly the last. At least for skins, most aircraft aluminum is actually alclad, as alloys with the desired strength-to-weight ratio are generally too vulnerable to corrosion to be exposed to the elements.
The cavernous interior of the ZPG-2’s gas ‘bag’, looking forwards. The ballonets have not yet been installed. Image credit unknown, via Aviation Rapture
So, contrary to popular belief, no tin was involved. And the sturdy aluminum spheroid was not at all flexible, so the ZMC-2 was not really any kind of blimp. It also was not, technically, a Zeppelin. It was a whole new beast: a metalclad airship.
There is a film of the ship being built, and it’s rather fascinating. The strips of alclad are rolled into conical sections and riveted together, with a bituminous material serving as sealant. Even today, you would not want to weld this material, so instead three and a half million 0.035” (0.89 mm) rivets hold the plates together. A special automated riveting machine was invented for the construction of the metalclad airship, which “sewed” three rows simultaneously at a rate of five thousand rivets per hour.
Just like most monocoque airplanes, then and now, the skin doesn’t hold the entire load: there were five circular frames, flanged and full of lightening holes just like the ribs of an aeroplane fuselage, of various diameters to help the ‘gas bag’ hold shape. The gondola would attach to two of these.
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Amazingly, with all of those rivets and the low-tech sealant, the metalclad held helium much better than its rivals. Yes, helium. While more expensive than hydrogen, the US Navy had already transitioned away from that more volatile gas and had no interest in going back. All of their groundside infrastructure was centered around helium. If that meant that the fireproof metalclad would not be able to lift quite so much as it otherwise might, well, too bad.
By the time the ZMC-2 got to Lakehurst as pictured here, only helium was on tap. Image: Navy History and Heritage Command
OK, It’s a Bit Like a Blimp
Aside from outward appearance, the metalclad airship is similar to a blimp in some respects. For one, like the blimps that would go on to serve into and well past WWII, and unlike every Zeppelin ever built, the metalclad design had no internal subdivisions. The great metal balloon, 52 ‘8 ” in diameter (16 m) and 149’ 5” (45.5m) long, held two air bladders, one fore, and one aft, but was otherwise cavernously empty.
Just like the blimps, those air bladders were used for trim: by pressurizing the fore bladder, the nose becomes heavy and trims the blimp down; likewise pressurizing the rear bladder trims the nose upwards. With both under pressure, the overall excess lift of the gasbag is reduced slightly, though the hull was not designed to withstand enough pressure for that to be notably useful at affecting overall buoyancy. The maximum the ZMC-2’s hull could take was said to be about two inches of water, or 0.07 PSIg (0.5 kPa).
Also like a blimp, that pressure was required to resist the force of aerodynamic drag, at least at high speeds. The aluminum skin could hold its own shape, obviously, and even at low speeds it was safe to fly at atmospheric pressure, but at speeds above about half velocity never exceed (VNE) there was a risk of buckling the nose. So, like a blimp–or the balloon tanks on the much later Atlas rockets–gas pressure was used as reinforcement. For that reason, there was much consternation at the time–and since–whether to count the metalclad as a rigid or non-rigid airship. Ultimately the US Navy, whose code was “Z” for airship and “R” for rigid or “S” for non-rigid, called it ZMC– z-airship, metal clad. That dodged the issue well enough.
A larger ship might have been able to afford the weight of stronger aluminum to take the buffeting of high-speed flight, thanks to the square-cube law, but the comparatively tiny ZMC-2 lacked that lift capacity. Even larger ships were always intended to use pressure-reinforcement; it’s a key part of the metalclad concept. Why waste lift capacity on metal when the gas can do it for you? As it was, the useful load of the prototype ZMC-2 was only 750 lbs (340 kg). The ZMC-2 wasn’t designed for useful load, though; it was only ever meant as a testbed.
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Flying the Tin Blimp
As a testbed, the ZMC-2 was reasonably successful, and also a complete failure. It was reasonably successful in that its logbooks recorded 2,265 incident-free hours over 725 flights between its debut in August 1929 and its grounding in August 1939. In those ten years, it was found to fly well, in spite of its oddities.
The control car, with its crew of two or three–plus four passengers–and a pair of 220 HP Wright Whirlwind engines, would not have looked out of place on a blimp of similar size. Its overall size was not unlike blimps Goodyear was flying. Nor was the ZMC-2 particularly speedy, or unusually slow with a top speed of 70 mph (113 km/h). Aside from the metal-clad construction, two things made the ZMC-2 stand out amongst its contemporaries. The empennage — the “tail” — was perhaps unique in airship history– as near as I can tell, the Detroit Airship Company was the only one to ever fit eight equally-spaced fins to the rear of an airship. All had control surfaces, and in practice, there was no control mixing: four acted as elevators, and four as rudders. It worked well enough, as the ship was apparently quite maneuverable.
The only thing normal in this photo is the gondola. Note the four visible tail surfaces– there are four more on the other side. Image: Screenshot from “Tin Balloon” (Silent) by zrsmovie.com
The other oddity helped with this maneuverability: the airship’s fineness ratio. It was oddly squat, at only 2.83. Like much in the world of airships, the concept of a fineness ratio is borrowed from the naval world– there, it is the ratio between a ship’s length and its beam, or width. For a flying ship, it’s the length to diameter of the gas bag, but the effect is the same. Picture a racing skiff vs a coracle, or a whitewater kayak. The racing skiff has a very high fineness ratio, which gives it high speed and low maneuverability as it cuts through the water. A coracle or whitewater kayak, on the other hand, has a low fineness ratio, often less than two, so that they can turn on a dime. They’re also incredibly difficult to keep going in a straight line. The ZMC-2 wasn’t quite that squat, but from the boating analogy I can only imagine it was a handful to keep on a straight course at times.
ZMC-2 looks positively squat at top-right, compared to ZR-3 Los Angeles at center and the J-2 blimp on the left. That has pros and cons but was not an inherent characteristic of the metalclad concept. Image: Naval History and Heritage Command
The only reason I dare call the fabulous tin blimp a failure is because there was no ZMC-3, or -4, or N≠2. It was indeed the only metalclad to ever fly.
One of a Kind
It wasn’t the cute little prototype’s fault; it was the timing. The Detroit Aircraft Company launched the ZMC-2 with big plans– Upton’s first design was for a larger express passenger/cargo airship of 1,600,000 cu.ft. (45,307 m³) gas volume, compared to the meager 200,000 cu.ft. (5,663 m³) of the prototype. There was interest in the bigger designs, but the ZMC-2 would need to prove the concept– which it did, in August 1929. Then in October, the stock market crashed, the Great Depression hit, and there was a lot less money available for pie-in-the-sky ideas like metalclad airships.
The interest was there, mind you. The U.S. Army liked what they saw, and went hat-in-hand in 1931 to Congress asking for 4.5 million to buy a 20-ton-lift model that would have been larger than the Graf Zeppelin. At that point, Congress felt there were other priorities. Later on, Detroit’s metalclad design was The Navy’s preferred choice to replace the ill-fated Akron and Macon, but there were problems with funding and the Detroit Aircraft Company didn’t have a hangar big enough to build the thing in anyway.
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The Army’s large metalclad might have looked like this, according to Popular Mechanics Image: Popular Mechanics April 1931, via lynceans.org
That was the end of it. Though there was no notable metal fatigue or corrosion, the ZMC-2 flew less and less as the odds of a successor dropped. Some accounts claim it was grounded completely in 1939; others imply a handful of flights until US entry into WWII. With the war on, aluminum was in short supply and the ZMC-2 was broken up for scrap in 1941. It was simply too small for the antisubmarine duty the Navy’s blimps were being put to, and too weird to use as a training ship. Though the gondola was kept for a time as a learning aide for ground school, it was not preserved. It is likely that no physical trace of the fabulous tin blimp remains.
Legacy
Ultimately, the ZMC-2 was successful in proving that a metalclad airship could fly. During the various aborted attempts at an ‘airship renaissance’, various proposals for metalclads or similarly-built composite ships have been put forth, but as with Ralph Upton’s larger designs, no capital sufficient for construction ever materialized.
In spite of my praise of the non-rigid airship’s ability to shift with the winds– going so far as to say “Blimps win” in my last article, based on the historical record, I for one would love to see a metalclad fly again. Maybe it’s just the Rule of Cool– rigids are cooler, and metalclads are cooler yet. Maybe the image of the doughty ZMC-2 buzzing about like a giant, clumsy bumble bee has made me sentimental for the design. Maybe it’s just that there’s potential there. Thanks to the great Nan ships, we’ve got a pretty idea of what non-rigid airships are capable of. ZMC-2 only scratches the surface of what a metalclad could do; perhaps someday we’ll find out. With modern lithium-aluminum alloys being that much lighter, or the ‘black’ aluminum of carbon composites, we could probably build something exceeding Ralph Upton’s wildest dreams… if there was money to pay for it.
12 years was a good run for a prototype. So long, and thanks for all the AvGas. Image: Naval History and Heritage Command
When comparing engine specs for nearly any combustion engine automobile, we see a number of variations available with differing outputs of horsepower and torque. We often have a choice of gasoline or diesel engines with a range of cylinder counts, arranged in inline or V formations.
If we really dig into the minutia of engine specifications, we’ll find a figure for compression ratio that looks something like 9.5:1. The compression ratio relates to the engine cylinder’s maximum volume with the piston at the bottom of its stroke compared to the volume at the top of the stroke where the combustion chamber is at its smallest.
Increasing the gasoline engine’s compression ratio, say from 9.5:1 to 10.5:1 means that the air-fuel mixture inside the cylinder gets compacted into a tighter package at the top of the stroke before ignition. For example, a 5.0-liter V8 engine contains about 0.625 liters per cylinder. At a 9.5:1 compression ratio, the cylinder’s 625 cc volume is squished into a 65.8 cc space, while at 10.5:1 that space shrinks to 59.5 cc.
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YouTuber Engineering Explained tells us that increasing an engine’s compression ratio increases its thermal efficiency. Their calculations show the mathematical differences between 9.2:1 and 14.0:1 compression ratios give the higher compression engine a 6% power advantage. Hot Rod doesn’t share the math, but claims, in simple terms, that increasing the ratio by 1.0 within the range of common automotive compression ratios could deliver power gains between 2% and 4%. The magazine also points out that the published compression ratios relay theoretical static compression values, while dynamic compression ratios found in the real world are affected by factors such as valve timing.
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Higher compression diesel engines are more efficient than gas
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Diesel engines are more efficient than gas engines, thanks, in part, to their relatively high compression ratio. It also helps that diesel contains 15% more energy density than gasoline, but that’s a story for another time.
Diesel engines typically operate with compression ratios ranging from 14:1, which is the upper end of high performance gasoline engines, all the way up to 25:1. One way that diesel engines benefit from higher compression ratios is the heat generated by compressing air beyond 16:1. While a gasoline engine uses a spark to ignite the compressed gasoline mixture, a diesel engine relies on glow plugs for cold starts and high compression ratios to create temperatures up to 1,000 degrees Fahrenheit, more than enough to trigger combustion of its precisely-timed diesel fuel injections.
Generating such high compression ratios takes away some internal combustion engine efficiency. However, the increased cylinder pressure at the time of combustion translates into more power, primarily the torque for which diesel engines are known. In addition, the smaller combustion area of high compression engines (up to 16:1) allows the fuel load to burn quicker and more thoroughly, reducing ignition delay, reducing emissions, and increasing fuel economy.
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Why don’t all engines use higher compression ratios?
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If diesel engine efficiency and performance benefit from increasing compression ratios, why not use the same formula for gas engines? While it’s true that diesel engines exhibit greater efficiency and better performance with higher compression ratios than those typically found in gas engines, there is a point of diminishing returns, and like most mechanical things, there are tradeoffs.
Among the leading factors limiting compression ratios in gasoline engines are detonation and pre-ignition of the fuel load inside the cylinder. While internal combustion engines rely on the combustion of the fuel load during the engine’s power stroke to drive rotation of the crankshaft, the process must be controlled and precisely timed for optimum efficiency.
In a gasoline engine, combustion timing is ultimately controlled by the spark plug. If a gas engine develops excessive dynamic compression, whether from designed static compression ratios, forced air induction, or valve timing, higher internal cylinder temperatures could cause the air-fuel mixture to spontaneously combust sooner than designed, resulting in pre-ignition.
Detonation inside the cylinders is also caused by excessive heat and pressure. However, it occurs after the spark. Instead of a controlled fuel burn radiating through the combustion chamber from the spark plug located near the center, the fuel explodes, or detonates, violently.