Also see:  Best Power Bank Deals For a device of this capacity it’s small and sturdy, thus highly portable, and features a premium design with a high-gloss finish. A tapered top section combines with a single finger groove on each side to improve grip on its slippery surface, and there’s a soft carry case in the box to keep everything together (including the cables) when you’re out and about. We’re especially impressed by the LCD screen, which tells you the exact battery capacity remaining. In theory you’ll never get caught short, finding yourself away from home with a flailing smartphone battery and no way of refilling it. There is one LED on this power bank, but it isn’t used to tell you how much power remains. Rather, a double-tap of the button on the front and it lights up to become an emergency flashlight. The Magnum Opus Mini is not the brightest torch, and this LED does cheapen the overall design somewhat, but it could get you out of a fix as you’re struggling to find your way in the pitch black of night. Probably better to have it than not, just in case. Despite its small size there are two USB outputs, and Micro-USB for refilling the power bank. CHJGD has been rather secretive about the exact specifications of the Magnum Opus Mini, but confirms that it supports Quick Charge 3.0 to help charge your compatible phone or tablet faster. Also see:  How to charge your phone’s battery faster  We’ll assume it has the same setup as its bigger brother, with the input but only one of the two outputs supporting the fast-charging technology (the other a still fast 10W port). CHJGD says you can refill the Magnum Opus Mini in around five hours. One thing we can’t tell from the specifications provided is the maximum total output power of the bank and whether it can simultaneously support both those outputs at full-speed. Even if this isn’t possible, though, the ability to charge two devices from one bank could prove very useful away from mains power. See all  power bank reviews Another thing CHJGD neglects to mention is the efficiency of the LG battery inside. Most power banks settle between 60- and 70 percent, so you can work out how many full charges that translates to for your specific model of phone. A 10,000mAh charger such as this will typically offer an Android phone two full charges, and an iPhone three. Charging is automatic, so just plug in your device and off it goes. The Magnum Opus Mini does not support passthrough charging, which is the ability to recharge its own battery while recharging connected devices. That’s a shame, since you’re likely to want to charge both the bank and your phone overnight and will therefore need two mains adaptors (and two spare sockets) or a USB hub powerful enough to handle both. Read next:  How to improve smartphone battery life 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.