If 120-degree summer heat and 70-pound packs weren't enough, American troops in Iraq have been getting sapped of energy by a surprising source: their own batteries.
On a typical three-day deployment, soldiers carry around 65 batteries — weighing up to 30 pounds — to power their night-vision goggles, flashlights, GPS and other tools. This is in addition to a significant amount of dead weight in body armor and Kevlar.
Now Lockheed Martin has stepped up to solve both problems in one go. It plans to turn a soldier's body armor into a power source, making the armor rechargeable and its total weight minuscule.
If it succeeds, the armor could also solve another power problem. An estimated 40 percent to 50 percent of battery energy is wasted because key parts of a soldier's kit don't have a sleep mode to save power while they're inactive. That means normal batteries just run out.
Lockheed's body armor would manage power and incorporate a standby mode, meaning those critical tools could last even longer.
The research has been sponsored by the Defense Department's Advanced Research Projects Agency and has passed initial tests.
Richard Edwards, vice president of Tactical Missiles and Combat Maneuver Systems at Lockheed, says the armor is safe and viable. Initial data suggests the armor can power up while successfully stopping small-arms fire.
With the race to solve the power puzzle, the folks at Lockheed aren't the only ones who see a future in rechargeable technology.
Scientists at Georgia Tech have created a wearable power source they call the "power shirt," a device packed with nanowires that could harness the body's kinetic motion, even down to the flow of blood beneath the skin.
Tiny wires attach to fibers in the shirt and tap into a soldier's body movement, combining the electrical flow from many fiber pairs woven together. It could generate enough electricity to power a range of small electronic devices.
More than just shirts could become power sources; by weaving the fibers into other materials, Kevlar jackets and even tents could utilize the technology to draw energy from sound vibrations or wind motion.
Still, moisture from sweat — or worse, a washing machine — could pose a problem for the shirt's zinc-oxide wires. But the shirt could suffice for the moment, as some soldiers would rather stink than have to break their backs for batteries.
This fall, the Defense Department is sponsoring a $1 million prize for developing a wearable power system that weighs under 4 kilograms (8.8 pounds) and provides power for a four-day mission.
Should one of the 100 teams competing for the prize succeed, and if these technologies take off, American troops soon could be carrying a much lighter load.
Allison Barrie, a security and terrorism consultant with the Commission for National Security in the 21st Century, is FOX News' security columnist.
Allison Barrie consults at the highest levels of defense, has travelled to more than 70 countries, is a lawyer with four postgraduate degrees and now the author of the new book "Future Weapons: Access Granted" covering invisible tanks through to thought-controlled fighter jets. You can click here for more information on FOX Firepower columnist and host Allison Barrie and you can follow her on Twitter @allison_barrie.