At first glance, German-based start-up Changers is offering nothing new with its solar powered battery charger. Solar powered chargers have been on the market before but Changers offers more than a green way to charge up your electronic devices. It wants you and your friends to join the greenest social network on the internet to date.

Changers, backed by German solar-tech company Centrotherm, unveiled their new device in San Francisco on Thursday a small charger powered by solar energy. The module, called Maroshi, can be charged by clipping it to any window or sunny surface. The energy is collected in a solar battery, called Kalhouhfummi, and can power up any electronic device as quickly as any wall socket will.

However Changers, founded last year by Markus Schulz, Daniela Schiffer, Dirk Gamboa and Hans Raffauf is more than solar powered batteries, it's also about changing people's attitude towards green energy by making it a social network.

"We are launching the first social energy marketplace with the aim to allow everyone to produce their own energy and measure the amount of energy they save," said Hans Raffauf, co-founder and director of communications at Changers.

"We want to enable every single person to produce their own energy, and in doing so, think more consciously about it."

Kalhouhfummi, the Changers battery can also track how much power it generates. The data is uploaded to an energy marketplace at the company's website, Changers.com which also serves as a social hub for Changers users. They can compare and compete based on their energy savings via other social networks like Facebook or Twitter.

"People like to compete, and here they can compete in something sustainable," said Kushtrim Xhakli, who oversees digital media for Changers.

Changers is hoping that a few popular users on the social networks can spread the word about the green device and convince their friends to also participate.

"If you really want to have an impact on global warming, you've got to start with the end customer and change their behavior," Raffauf said.

And if beating your friends at being green isn't enough incentive, how about getting paid to save the planet? Changers is also offering monetary rewards for those who use their solar battery and charger.

"We will give people credits each time they charge a mobile phone; these credits can then be used to buy something online from the Web site Holstee.com," Raffauf said. "People will be given a credit of $1 for each watt hour of energy they save."

Credits that users earn thru Changers can exchange those credits for compensation in popular online games like Farmville.

Changers is now taking pre-orders of its Changers starter kit for $149. The starter kit will come with the solar battery and module as well as eight adapters. The product can connect to more than a thousand devices.