Kang Xu, an Army Research Laboratory scientist, is one of the inventors responsible for a 30-percent increase in energy density in lithium batteries. The work is part of ongoing research to increase the energy of batteries while lowering their weight, to reduce the burden soldiers carry in the field. (Source: Army)
If you add the "balance of plant" to the fuel cell i.e. air supply, fuel tank, pumps, valves, converters, inverters, etc. it isn't necessarily the most efficient source of power. The only reason that the shuttles, etc used them was due to the tons of H2 they had to have anyway for other things (like the big burner at the bottom).
The fuel cells only real advantage is that of being a battery that can be recharged instantly (assuming that their is a handy H2 source around your tent.
If you carry methanol the efficiency is a small fraction of that of a pure H2 cell. If you carry hydrogen it has to either be compressed (very low density storage), liquid (cryogenic problems) or hydride (weight problems).
Maybe solid oxide might work because it will run off most anything but operates at pretty high temps.
Robat, a sniper left on a hilltop for days isn't a regular load. But you make my point exactly that a generator is nessasary. It's probably the best use of a foolcell as such low level power needs is easily done by a small 10-50 wt fuelcell like are available to power laptops.
Next a solar panel or small wind/rivergen weighing a lb or 2 could supply needed power. And can be made stealth.
If hiking or while sitting, a foot/leg, gravity, etc motion generator is doable.
The best way is reducing power needs by more eff equipment because like on the grid, the power you don't use is the cheapest of all.
And why are soldier carrying such loads degrading their performance? Why not have hip hitched cart/packframe carrying it so the soldier doesn't have to hold up 100lbs they do too often, just pulling it instead. If it's a tent/bed made from kevlar it eliminates those and provides cover even when caught in the open at no extra weight.
As much as I would like to complain about govt. spending just may be Dr Xu has something.
I was told by an upper level DOE guy at their annual Fuel Cell Seminar a few years ago that the majority of the weight that soldiers carry IS batteries. The next item is food and water. If for example a sniper in Afganistan has to sit on top of a mountain for a few days he needs power for his radios, night vision, etc. A generator is a problem because most technologies make noise when they are operating. Even a fuel cell needs plumbing, fans, etc that are a problem to design to be absolutely silent.
Army research scientists are working on patents for this? Does this mean that the US government will license the technology for civillian applications, or that non-US military contract manufacturers can just forget it?
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Engineers at the University of San Diego’s Jacobs School of Engineering have designed biobatteries on commercial tattoo paper, with an anode and cathode screen-printed on and modified to harvest energy from lactate in a person’s sweat.
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