HYmini

The HYmini offers the best of both worlds: it will charge via the optional external solar panel when it's sunny, but should the weather take a turn for the worse the wind turbine will continue topping up its internal battery.

It supports an impressive range of gadgets: a standard powered-USB port and a range of power adapters mean that almost all popular devices are compatible.

Our favourite way to use it was with the optional bike adapter. This lets you bolt it to the handlebars of your bike, collecting wind power as you ride.

We found that a six-mile commute was enough to charge a Nokia E65 to half capacity. Of course, if you're not feeling that energetic, placing it on a window ledge will let you harness the power of any passing breeze.

The plastic body is able to stand up to the scrapes of life spent between the handlebar and windowsill. Just steer clear of the green-coloured model: it's a cliché.

Author: Matthew Sparkes