Portable energy firm Moixa has launched an AA battery that can be charged from any USB port. 

The USBCell is the same size as a regular AA battery, but features a standard USB connector at the top covered by a cap. To recharge the unit, all the user needs to do is plug it into a powered USB port. 

USBCell is currently available in the AA format only, but a full range of standard battery types will be available in the new year. Batteries for popular phones and cameras are also in the pipeline.

The unit offers about 30-40 per cent less capacity than a standard rechargeable battery, according to Moixa, owing to the space required to accommodate the USB plug.

The batteries are rated for 500 recharge cycles and only exhibit a slight memory effect. According to Moixa, after a year's typical use capacity will only decrease by about five per cent due to partial recharging.

"There are several billion USB sockets in the world today on computers and many other devices that can provide a source of low-voltage power," said Simon Daniel, director of Moixa Energy.

"USB sockets are so accessible to consumers that you can recharge practically anywhere, whether travelling, at home or in the office.

"Most importantly, with the USBCell you don't need to worry about carrying additional mains chargers or adaptors."

A pack of two AA USBCells can be purchased online for £12.99. Moixa also promises to refund any units if customers find that their USB ports do not supply sufficient power to recharge the devices.