On Wed, Jun 08, 2016 at 11:07:17PM -0400, Richard Aiken wrote:
> Speaking of reducing loads and all those batteries to carry
> . . . why don't they give everyone one of those modern hand-crank
> generators that are about the size of a smart phone?

They are pretty pathetic.  A good one will generate about 10 watts,
while seriously tiring your arms.  A less good one will generate less,
and also be heavy and break pretty easily.  Good or bad, getting them
sandy or muddy is very detrimental to their lifespan.  That could be
addressed for military use, though no doubt at a cost in extra mass.

A decent AA battery provides about the same energy as cranking for
twenty minutes, while having about 1/15-30th the mass of a few typical
commercial models I found specs on, designed for being easy to carry.
You would need to crank for about 10 hours to break even on load, more
for a ruggedized version suitable for military use.

Their main use is that they can sit on a shelf for a decade without
losing charge or corroding to uselessness, then grabbed to run
something for a few minutes in an emergency.

- Tim