RF battery chargers will be coming soon from Powercast. The chargers work by emitting an RF signal from an attachment to a powered source such as a lamp. There is a receiver that is placed with the battery which constantly charges the battery. The RF signal apparently does not have a very long range - the article does not make it clear if this is due to government regulations or a technological limitation. My mind is drawn to the works of Nikola Tesla who is said to have developed a similar technology 80 years ago (which may have been used to power an AC car).