Building on the success of short-range induction charging, such as is used in the MobileWise wire-free electric power technology, Posicharge, Inc. has introduced the latest advance to wireless networking technology: the Tes-La passive energy charging system. When a Wi-Fi hotspot adds Tes-La coils to their wireless gateways, your laptop pulls voltage from the air using a system similar to that which allows drivers to debit charge accounts as they zip through special toll gates.
<http://www.mobilewise.com/>
<http://www.tes-la.us/>
A laptop requires a special antenna-like adaptor that replaces the power adapter that comes with the machine. Although power can be transmitted over thousands of feet, its strength dissipates as you move away from the Tes-La coils. It's highly recommended that you wear a grounding strap or constantly touch metal while using the Tes-La system to avoid static discharge (Posicharge offers a pair of grounding straps designed to look like fashionable wrist apparel instead of cheap Velcro straps).
What's fascinating about Tes-La is that it's not a dumb system: it uses a power delivery protocol called TCP/EP, or TCP over Electrical Power. TCP/EP can be metered by measuring the outgoing amperage contained in each packet. A laptop negotiates its power needs through the protocol. For example, when you first connect the battery is quick-charged to about 70 percent of capacity; then the amperage is throttled back to a slow trickle to top off the remaining capacity. Another advantage to this approach is area-wide power consumption: the system doles out power based on the number of users in the vicinity, averaging the outgoing power among multiple users.
<http://www.tes-la.us/technology/>
However, the Tes-La system is not without its flaws. Sending power through the air has been a dream of the modern age since the 1920s, but the dangers associated with it can't be understated. One of Posicharge's competitors, Noside Connections, alleges that if one were to place a dog in the direct path of a Tes-La transmitter, the animal would be fried in a manner of minutes (Noside assured us that the example is theoretical, and that no animals have been tested in this manner).
Posicharge, in response, notes that the Tes-La system is designed to step down its power when it senses interruptions, and that dogs are rarely found in the cafes and other public establishments in which Wi-Fi is traditionally offered.
Tes-La should be available in the United States once the FCC, FDA, FAA, USDA, NSA, DHS, and other governmental agencies provide their approval.