Phone batteries dying, spiderwebs of power cords — powering mobile technology can be pretty annoying for the average iPhone or iPad user.  But it’s ever more annoying — not to mention potentially dangerous — if you’re a soldier on patrol in Afghanistan losing juice on a critical gadget. Yes, troops in the field use their fair share of handheld gear, too. Now, the Pentagon is hoping to give them a power up with a wireless charging system.

Darpa, the Defense Department’s advanced research shop, announced Wednesday that they’re looking to build a short-range wireless power transmission system for troops in the field. The transmitter would allow troops to charge up things like GPS without having to stop and plug in. If the system works, a single GI could strap on a battery pack and allow other troops to draw power from it wirelessly at a distance of up to two meters.

The push for wireless power is a problem born of an increasingly technology-equipped military. GIs in the field lug a lot of handheld electronic gadgetry — about five to ten pounds of just battery weight, according to Darpa. On top of that, the Defense Department keeps coming up with ideas for yet more portable electronic gear, from Android-based smart phone to universal translators. All that gear needs juice to keep going on long missions. If troops are out on patrol, they can’t just find a convenient socket to stop and plug in. Darpa’s hoping its wireless power system can prove a solution to energy needs in the field without adding a tangled mess of charger cords.

Wireless power transmission may sound like Tesla-inspired science fiction, but the technology behind it isn’t that exotic. In fact, you may have brushed your teeth with it this morning. Electric toothbrushes use a form of wireless power transmission called inductive coupling. A coil in the plugged-in charging station creates a magnetic field that allows current to transfer when a coil in the toothbrush enters the field. Microwave power transmission, another method of wireless power transfer, uses microwave-beaming antennas to power devices across distances.

There’s already quite a few wireless systems available. Powercast (pdf) makes a transmitter that uses radio waves to transmit both data and power. If you’re in the market for a home-use system, microwave-based wireless extension cords are available on the Internet. For naval super users, Rensselaer Polytechnic Institute doctoral student Tristan Lawry has built a system that can shoot power through ship and submarine hulls with ultrasound.

Darpa, however, is looking for a wireless power transmitter that’s customized to the needs of troops in the field. If you plan on pitching the agency, your system needs to have an efficient distribution of power from end to end and work with a range of different portable electronic devices. Safety is key, too. Make sure your power transmitter doesn’t easily give up users’ position or have any lingering health effects from radiation.

Photo: The U.S. Army/Flickr

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