Enough sunlight falls onto Britain in less than 45 minutes to supply the nation's energy needs for an entire year.

We're generations away from being able to tap into a significant part of that, so a little bit of free electricity always appeals.

The bad news sets in almost immediately. You can't charge devices directly - the solar panels can't deliver a charge fast enough, apparently - and so you first have to charge the Free Loader's internal battery, then dump that power to your device.

A struggle to charge

Next, charging times. You can charge it over USB - fast enough to be usable - but charging using the power of the sun takes much longer.

The manual says that a day in full sun is enough to charge the battery, but this triples when you keep it behind glass, whose UV filters cut down the potential energy, and you have to contend with cloudy days, too.

Unlike charging over USB, there's no way to know when the battery is charged. Three different LEDs light and change colour to inform you of charging status, but the system is rather clunky.

Use with your iPhone

A fully charged battery is able to supply a fair bit of power; it charged an iPhone halfway, giving 2 hours, 20 mins of talk time.

It includes charging adaptors for the iPod (up to 60GB), Nintendo DS Lite, LG Chocolate series, Nokia, Samsung and Sony Ericsson mobiles, the PSP, Tom Tom and digital cameras, and anything that charges over USB; extra connection tips are available.

After a full week of charging on a windowsill in early spring, it was only juiced up enough to provide 50 minutes of iPhone talk time. Remember, though, that the iPhone is a complex beast; a little entry-level Nokia would probably get more.

The Free Loader, then, is cheap enough for it to be a handy source of emergency power on your car's dashboard, but don't expect to sever your connection to the national grid.