At 10x75x20mm and 236g, Sandberg’s PowerBank 12000 is a small power bank, given the capacity on offer. With 12,000mAh inside (expect no more than 70 percent to be available to your devices) the Sandberg can charge a Samsung Galaxy S6 three times or an iPhone 6 4.5 times, yet it’ll still slide into a pocket or bag. Made entirely from plastic, a simple grey strip runs around the edge, and is sandwiched in between a matt black front and back. The Sandberg has a solid build, which doesn’t look easy to break. Nevertheless, a generous five-year warranty is reassuring. Also see: How to improve smartphone battery life. At this price, though, we would have hoped the Sandberg PowerBank 12000 would feature passthrough charging, which allows you to charge both the power bank and an attached device simultaneously. Given that the Micro-USB input on this device is rated at just 5W, you could be waiting 13- to 14 hours to fill up the power bank, and then you’ll still need to charge your phone and/or tablet after (or find another plug socket). That’s quite inconvenient if you’re in a rush. Also see: How to charge your phone or tablet faster. Note that while a Micro-USB cable is supplied, as is standard for power banks there is no mains adaptor – you can use your phone- or tablet charger to fill it up. The output specification is better. There are two USB ports, one a standard 5W for phones and the other a fast-charging 10.5W port for phones and tablets. The Sandberg has a max total output of 3,100mAh, which means you can simultaneously charge two devices at full-speed. Also pleasing is the Sandberg’s auto-on and auto-off functionality, which means you don’t have to fiddle around with buttons to charge your device, nor watch for when it has finished charging to prevent power wastage. The display will also switch off a few seconds after charging has completed. Nevertheless, there is a power button on the PowerBank 12000. A double-press of this activates the built-in LED torch. Also see: Best desktop chargers 2015.
