Alxum 100W 4 Ports GaN charger review: Fast 4-way power

Multi-device fast charging brick is a hit.

Alxum plug
(Image: © Gerald Lynch/ iMore)

iMore Verdict

With four ports of simultaneous charging and a 100w max output, the Alxum is a compact and speedy power brick for all your most important devices.


  • +

    4-charging ports

  • +

    100W fast-charging output

  • +

    GaN charging technology


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    Power distribution for multiple devices can be confusing

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    Fast-charging should be used sparingly

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Got more devices that need charging than you have wall sockets to power them from? Then you’re in need of a good multi-device charger. While wireless mats and stands are in vogue, it’s still handy to be able to tether your devices to a wall when at a desk or traveling.

The Alxum 100W 4 port USB-C charger is a superb option in that case — with three USB-C ports, 1 USB-A, and 100W of Gallium Nitride (GaN) fast-charging power, it’ll juice your devices super speedily, and leave you with wall outlets to spare.

Alxum 100W 4 Ports GaN charger: Price and availability


(Image credit: Gerald Lynch/ iMore)

The Alxum 100W 4 Ports GaN charger is available now, available from Amazon US and Amazon UK and direct from Alxum. Expect to pay around £60 (about $75) for it. That’s right in the middle of what we’d hope to pay for a 4-port 100W GaN charger, with options from competitor Ugreen similarly priced.

For comparison’s sake, a 96W single-port MacBook charger from Amazon costs $79 / £79.

Alxum 100W 4 Ports GaN charger: What’s good?

Let’s start with what makes Gallium Nitride (or GaN, its chemical formula, as you’ll more commonly see it written) important. The crystal-like semiconductor material is starting to replace silicon in some transistor systems, as GaN transistors can be made smaller than silicon ones, can switch faster and carry more power efficiently. In other words, they can charge at higher wattages, faster, without overheating, in overall smaller devices.

GaN chargers can charge at higher wattages, faster, without overheating.

The Alxum charger manages to do all of that, with a brick about the third of the size of Apple’s equivalent-powered charger, and weighing just about 300g in the process. Black with a textured wave finish that makes it easier to pull out of an outlet, it’ll protrude from a wall about 7cm when plugged in, is about 2.6mm wide and 5cm tall.

With four ports (three USB-C, one USB-A), the Alxum charger intelligently distributes power depending on what ports you’re using, and what’s plugged in, aiming to keep all your devices charging safely. It’s quite a complex list of combinations and power supplies that can be sent from the charger, and is best illustrated by this chart provided by Alxum itself:

Alxum plug

(Image credit: Alxum)

In short, using either or the top USB-C ports individually will give you a 100W power supply, while using all four ports will separate it out into 45W, 30W, 7.5W and 7.5W, working down through the ports respectively. There are plenty of other distributions when using two and three ports, too.

Across all of them, the Alxum 100W GaN charger worked speedily to power devices, and was always recognised by the devices being juiced up — though there was sometimes a delay when adding a new device to the chain. Charging speeds will vary depending on what you’re looking to power, but both the PD3.0 and QC3.0 fast charging protocols are supported, and there’s UKCA & CE certification, protecting against overcharging, over-heating, over-voltage, and short circuit issues. In our testing, we experienced no problems, with the plug staying relatively cool even under heavy loads.


(Image credit: Gerald Lynch/ iMore)

Alxum 100W 4 Ports GaN charger: What’s not so good?

It’s hard to find fault with the Alxum 100W 4 port charger — it charges multiple devices quickly and safely, and there’s not a lot to complain about with how it does so.

One thing that could be improved would be illustrating the power distribution option on the charger itself. Knowing what combination of ports was going to deliver what power supply is an exercise in trial and error until you memorize what each combo does. It’d be better to have a chart like the one above printed directly onto the side of the charger for future versions, for instance.

And while this isn’t a fault of the Alxum device itself, we’d still encourage readers to use fast-charging methods sparingly. While the standards are safe, their overuse can be known to affect the lifespan of batteries.

It’s worth noting to that if you have a 16-inch MacBook Pro, and are used to fast-charging it with Apple’s 140W USB-C power adapter, you’re not going to get the same result.


(Image credit: Gerald Lynch/ iMore)

Alxum 100W 4 Ports GaN charger: Competition

There’s a lot of competition starting to grow in the GaN charger space, but the Alxum model here is among the best. You can get similarly spec’d chargers from Spigen and Ugreen for a similar price, but for the most part you’re looking at just aesthetic differences when it comes to brands you trust.

Alxum 100W 4 Ports GaN charger: Should you buy it?

Buy the Alxum 100W 4 Ports GaN charger if…

  • You have multiple devices you want to charge at once
  • You need 100W of power
  • You want to reduce the number of power bricks you take with you when charging

Don’t buy the Alxum 100W 4 Ports GaN charger if…

  • You don’t have devices that benefit from 100W output
  • You don’t need to charge more than one device at once
  • You don’t have USB-C devices.

Alxum 100W 4 Ports GaN charger: Verdict

The Alxum 100W 4 Ports GaN charger is just the sort of no-nonsense charger we’re into. Affordable, fast, well spec’d and flexible enough to handle a menagerie of devices, it’ll safely keep all your gadgets, from iPhone to MacBook, topped up with power.

Gerald Lynch
Editor in Chief

Gerald Lynch is the Editor-in-Chief of iMore, keeping careful watch over the site's editorial output and commercial campaigns, ensuring iMore delivers the in-depth, accurate and timely Apple content its readership deservedly expects. You'll never see him without his iPad Pro, and he loves gaming sessions with his buddies via Apple Arcade on his iPhone 15 Pro, but don't expect him to play with you at home unless your Apple TV is hooked up to a 4K HDR screen and a 7.1 surround system. 

Living in London in the UK, Gerald was previously Editor of Gizmodo UK, and Executive Editor of TechRadar, and has covered international trade shows including Apple's WWDC, MWC, CES and IFA. If it has an acronym and an app, he's probably been there, on the front lines reporting on the latest tech innovations. Gerald is also a contributing tech pundit for BBC Radio and has written for various other publications, including T3 magazine, GamesRadar,, Real Homes, MacFormat, music bible DIY, Tech Digest, TopTenReviews,, Brandish, Kotaku, Shiny Shiny and Lifehacker. Gerald is also the author of 'Get Technology: Upgrade Your Future', published by Aurum Press, and also holds a Guinness world record on Tetris. For real.