Power-hungry devices challenge army researchers.

• Author: Magnuson, Stew

* Dismounted troops know that they will always have an adequate supply of food and water in any operation. The Army spends billions of dollars to ensure that's the case.

"The assumption now by soldiers is that they are always going to have power," said John P. Howell, project director of soldier systems integration at the Army's project manager soldier warrior. "We are trying to fix that assumption and make it a fact."

Soldiers on foot need to have enough portable energy with them to make it through a 72-hour mission without resupply. The plethora of devices they carry with them is growing and making that harder--unless the Army wants to simply burden them with more batteries.

"It necessitates some fairly creative operational processes to make sure that a soldier stays powered up during an entire 72-hour operation," Howell said.

The power challenge continues to grow as soldiers are asked to carry more electronics with them on missions. Those might include GPS, gun sights, night vision goggles and radios. The latter is using up the most energy, Howell said.

"Radios are now not only just voice communication devices. They are constantly on, providing input and output of data and position location," Howell said. "They are very power hungry."

At the beginning of the Gulf War in 1991, a typical Army platoon required 1.74 kilowatts per hour to run their devices. Ten years later at the outset of operations in Afghanistan, it was 2.07 kilowatts per hour. Today, it has swelled to 31.35 kilowatts per hour, Howell said.

To get at the problem, the Army has developed a power management system that moves energy around a soldier as needed, rather than each different device being energized by its own battery or batteries.

The single power source is a lithiumion battery that conforms to the body and is worn inside a breastplate. Currently, that system is only supplying about half of the energy needed on a 72-hour mission. The soldier must carry a charged-up spare in his or her rucksack, which adds to the weight burden.

"Despite the technology--and as good as it is right now,... we've still got a long way to go," Howell said.

To make matters more complicated, project manager soldier warrior wants to make the power management system pull double duty and move data around the soldier.

Army Platoon Kilowatt-Per-Hour Requirements 1991 1.74 2001 2.07 2017 31.35 Basically, it is a router for power, Howell said.

There are seven inputs and outputs to distribute power...