Duracell Portable Charger 1800

Duracell's five-hour charger is designed to provide a boost to mobile devices such as smartphones and cameras while their users are out and about.

About the size of a pack of cards, the Duracell Portable Charger 1800 MAH has a detachable adaptor for UK mains sockets so it's more comfortable to carry while travelling.

Charging the device took just over an hour (although it came pre-charged) and when we tested it on an iPhone that was down to five per cent of its battery reserve, a recharge to 100 per cent power took a little under two hours.

However, within 15 minutes we had enough juice to make calls or use the mobile internet for a short period.

A three-bar display on the front of the device shows how much charge remains. Left unused, it remained at a full charge level three weeks later, although we found it would not deliver any power to our phone when it was down to a single bar.

The recharger has two USB sockets so it can charge a pair of devices simultaneously, although only one USB cable is supplied, with an adaptor for mini- or micro-USB sockets.

We tried charging two Android phones simultaneously and while one of them drew a charge of about 90 per cent from zero in just over an hour, the other stalled at around 60 per cent of its battery capacity.

Duracell told us that the product will provide enough power for five hours of use from a smartphone, but it's not really possible to quantify this because the rate of depletion will depend on how the phone is used.

Accessing a wireless network or using the 3G mobile broadband services employed by most smartphones will significantly reduce battery life. However, with a full recharge for a power-hungry smartphone delivered in about an hour, Duracell's charger did its job well.

At £30, Duracell's product is a little more expensive than some portable chargers but the added reliability and speedy charging and recharging make it a worthwhile buy.