When we first took the Xiaomi power bank out of its box we were confused. As is standard with Xiaomi products, all the writing on the box and in the supplied quick setup guide was in Chinese. We thought we were getting a 10,000mAh power bank, yet this thing is closer in size to the 6,000mAh Zendure A2 that previously topped our best power banks group test.  And, indeed, the specs mentioned something about 6250mAh. But we hadn’t been duped. Unlike many other power bank manufacturers we’ve encountered, Xiaomi is completely transparent with the fact that the entire 10,000mAh capacity will not be available to power your phone or tablet. Most power banks will lose between 30- and 35 percent of their battery capacity through heat generated and voltage conversion, so we wouldn’t expect to get any more than 7,000mAh from a 10,000mAh bank.

We think Xiaomi has been somewhat over-cautious with this 6250mAh rating in any case. The hardware inside has been optimised for increased efficiency and durability, which Xiaomi claims is up to 93 percent. We saw two full charges for our Samsung Galaxy S6 (2550mAh battery), and were still able to get a Ulefone BeTouch (also 2550mAh battery) to 75 percent. Also see:  How to improve smartphone battery life.  This isn’t the only thing Xiaomi has taken extra care over in designing its Xiaomi power bank. The fact that it has managed to squeeze so much power into such a compact 91x60x22mm design (725Wh/L) means this is the first 10,000mAh power bank we’ve seen that we’d happily slip into a pocket rather than a bag. No power bank makes a better compromise between portability and capacity.  We can’t fault the design and build quality either, and if it weren’t for the Micro-USB- rather than Lightning input and supplied flat white cable, the Xiaomi would look right at home in an Apple factory. Also see: Xiaomi Mi Band review and Xiaomi Wireless GamePad review.  

The safeguards extends to the Texas Instruments/MPS-designed circuitry inside, and the smart-control chips feature nine layers of protection, covering everything from temperature resistance and short-circuit protection to input- and output overvoltage. The indented power button at one end can also act as a reset button when required, for the power bank itself will automatically begin charging when you attach a phone or tablet.  Also see: Best MiFi 2016. With a single USB output you’ll be able to charge your phone or tablet, rather than both at once, but this helps to keep down size. Plus we like the fact the Xiaomi supports passthrough charging, which means you can charge both it and an attached device at once. Also see:  How to charge your phone or tablet faster.  

With a 10W Micro-USB input, using a similarly specified mains adaptor you should be able to refill the Xiaomi in roughly 5.5 hours. The USB output is also well specified, fast at 10.5W and offering automatic power adjustment to suit the attached device.  (Other Xiaomi products aren’t as easy to get hold of in the UK – see How to buy Xiaomi products in the UK.)  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.

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