The trouble with laptops is that if you use them for any length of time while you are out they always run out of battery and then they are just a dead weight to carry around.

One company however is hoping to change that will a little help from the sun.

The Voltaic Generator laptop bag is the first solar bag powerful enough to charge a laptop claim its makers.

According to the blurb it uses high efficiency solar cells to generate maximum power in the limited space available.

It includes a battery pack custom designed to efficiently store and convert the electricity generated. It can also charge cell phones and most other hand held electronics.

All you need is to leave the bag in the sun for a day and the solar panels will generate enough power to fully charge a laptop.

The bag will ship with common adaptors and you can charge other devices such as laptops, phones and other handheld electronics if you want.

The bag is big enough to hold a 17-inch laptop.