3 best portable chargers

You’ve switched onto low battery mode, your phone brightness is turned down all the way and you’re praying to the smartphone gods that your ever-dwindling battery survives until you make it to within reach of a plug socket. But despite your best efforts, your phone gives up the ghost.

If this sounds like an all-too-familiar scenario, a portable charger (for example: SUNJACK HEAT BANK ) would be a wise investment. From lipstick-sized packs that can give your phone – or any USB-chargeable device, for that matter – an extra bit of juice to see you through the next few hours, to larger, but still portable options that will revive your device many times over, the range is huge.

Just how many times over a pack can recharge your device depends on its capacity, and the capacity of the device itself. This is measured in milliampere hours (mAh). An iPhone 7, for example, has a battery capacity of 1,960mAh, while the Samsung Galaxy S8 packs a 3,000mAh battery. Larger devices, unsurprisingly, have much larger batteries – the 12.9in iPad Pro’s battery is 10,307mAh. To work out how many times your charger will recharge the device, divide the charger’s mAh rating by that of the chosen device. (So, a 10,000mAh charger will fully revive your iPhone 7 around three and a half times, considering no charger is fully efficient. To be sure that your device will get at least one full charge from the charger, make sure the phone’s capacity is no more than 70 per cent of the charger’s capacity).

And remember, depending on what device you’re looking to charge, you may need to carry round a separate charging cable, as not every charger is compatible. Check your connections before you buy.

1. Aukey 20000mAh Power Bank: £19.99, Amazon
This has an excellent capacity of 20,000mAh, which should give your iPhone 7, for example, around seven full charges, bearing in mind efficiency. Two USB ports give 2.4A output individually, or can combine for a speedy 3.4A, so it’s good for charging multiple devices at once. The charger itself can also be powered up by a lightning cable, which means you may only have to carry one cable around with you, device-permitting. There’s a built-in flashlight – you never know when you might need it – and although it’s not the best looking device around, it’s still perfectly portable at 388g. The power button lights up different colours to indicate battery level.


2. AmazonBasics Portable External Battery Charger 10,000 mAh: £16.99, Amazon
This charger is available with a range of different capacities, going from 5,600mAh to 16,100mAh – the former giving most smartphones at least one full charge, while the latter will deal with a hefty tablet. We found a happy melium in the 10,000mAh model, which strikes a balance between power and portability (it weighs 215g). There are two USB ports so you can charge two devices at once, and the 3.4A output means your devices will be charged quickly. Four LED lights on the front clearly show how much juice is left in the pack.

3. Proporta Stripe TurboCharger 12000: £40, Proporta
With a 12,000mAh capacity, this charger from Proporta will give multiple charges to all smartphones, and has two USB ports. Thanks to the 2.1A output, your devices will be revived quickly – Porporta goes large on its TurboCharge technology, and it seemed to have an effect on our devices. It’s durable, too, having undergone multiple drop tests in production (when we dropped it a few times in the office, it was entirely unscathed).