Whilst batteries are getting more efficient with each new release, forgetting to charge your mobile over night can still result in a dead battery by lunchtime. And whilst on the move, charging that device back up is a real problem.

Sony has come up with a solution. But you had best load up with elbow grease.

The wind up USB charger is the latest in the portable power charging market. The CycleEnergy USB charger has a built in hand crank which turns human power into smartphone power.

Due in Japan on the 20th of June this year, the unit will cost around $60, or 8,000 yen.

The unit has dual ports with is capable of charging two USB chargeable device. The modular charger also features a 4,000mAh battery, which is chargeable via AC power, for when you run out of elbow grease.

According to Sony the inbuilt battery has enough power to charge a smartphone two times. It also noted that it would take around two hours to fully charge a Xperia Acro HD smartphone.

The wind up equation gives you one minute of call time for every three minutes of cranking, and one minute of Web browsing in exchange for five minutes of work.

Source: CNET