This rugged power bank is unlikely to come into any harm from bumps and scrapes on the road, but it’s reassuring to see Anker offers an 18-month warranty with the Astro Mini. The Astro Mini’s closest rival is perhaps the Intocircuit PowerMini 3000. That power bank is a few pounds cheaper, but there are several reasons why this Anker is the superior product – and not just its more favourable design. First is its extremely high energy-efficiency. All portable chargers lose power through heat generated and voltage conversion during charging, so the advertised capacity will never be available to your mobile device. However, while the cheapest power banks average 65- to 70 percent efficiency, and some of the better models around 80 percent, this Anker Astro Mini manages a superb 90 percent energy efficiency thanks to Samsung Grade A cells and premium chips. This means that of the Anker’s 3200mAh capacity you can expect 2880mAh of usable power. That’s enough to charge pretty much any smartphone once, some handsets possibly twice. While the Intocircuit is only 200mAh lower in capacity, its lower energy-efficiency increases this gap. While the Astro Mini doesn’t support auto-on/-off (you tap the button to begin charging, and unplug your device to stop), in a device designed to charge your phone just the once it’s unlikely that there will be much remaining power to waste. The Anker also supports the company’s PowerIQ technology, which intelligently identifies a connected device and adapts to its recharge rate. Perhaps more useful in Anker’s larger-capacity power banks with higher-rated outputs (this Astro Mini has a maximum output of 1A or 5W), it’s an undeniably cool feature that meant the Anker was able to charge even our iPad mini, and iPads are notorious for being fussy about the devices from which they charge. Also see: how to charge your smartphone or tablet faster. In reality, of course, most smartphones you plug in will charge at the Anker’s full 5W, and in this respect it matches the Intocircuit. And when it comes time to refill the power bank, the PowerMini 3000 gets the upper hand with a 5W input – not that you’ll notice much difference when compared to the 4W of this device. Note that neither device supports passthrough charging. That’s to be expected at this price; just don’t try to charge the power bank and your phone at the same time. Another key difference between the Anker and Intocircuit is the Anker’s inability to tell you how much power remains, although the LED will flash when you hit 2 percent remaining. As is the case with the Veho Pebble Smartstick+, its LED is used to show only that it is charging your device or refilling its own battery. At this capacity that’s not a particular problem – you’ll likely need to recharge the Astro Mini each time you use it. Read next: How to improve smartphone battery life. Follow Marie Brewis on Twitter. Marie is Editor in Chief of Tech Advisor and Macworld. A Journalism graduate from the London College of Printing, she’s worked in tech media for more than 17 years, managing our English language, French and Spanish consumer editorial teams and leading on content strategy through Foundry’s transition from print, to digital, to online - and beyond.
