With all the portable USB devices we carry around these days, from phones, to ereaders, to cameras, to tablets, have you ever thought about the extra electricity we use to charge them? A new startup called Changers aims to make this less of a burden with a solution that’s both environmentally friendly and an online, social experience.

The Berlin-based team has developed a small, portable solar panel that charges a battery in a small box. The fully-charged battery then connects to your USB devices to charge them without ever having to hook up to a mains power supply. What’s more, the CO2 you’re saving by generating your own electricity is tracked on the Changers website, and you can share how much you’re doing for the environment on Twitter and Facebook.

What’s more, the startup is looking to turn this into a ‘social energy marketplace’, where CO2 savings translate into money off for users. The Changers is launching with one partner in this respect, online designer goods outlet Holstee. ‘Changers Credits’ – earned with your CO2 savings, convert into discounts. More partners will follow.

changers Charge lots of USB devices? Changers solar panel makes it a green, social experience

The company was founded around 18 months ago, founded by the former CEO of a marketing agency and an employee of one of his clients, who shared a vision of mass-scale consumer solar energy. The Changers now has 25 staff, including ex-eBay and Google employees.

changers shot Charge lots of USB devices? Changers solar panel makes it a green, social experience

We look forward to trying out a Changers unit to see just how effective solar charging of USB devices with an online social element really is. It’s certainly an exciting proposition.

The kit is available for pre-order from today at Changers.com, at an initial price of $149. It ships mid-November in the US, with a European launch planned for the first quarter of 2012.

Earlier this week, our very own Hermione Way caught up with Hans Raffauf and Kushtrim Xhakli of Changers at the Web 2.0 Summit in San Francisco. Watch the video to find out more.