I would think that a gell-cell with appropriate power converter, feeding
into the DC-in jack of a laptop would make a fine auxilliary power
supply.  You may need to pay a lot of attention to end-of-life
conditions: I expect a laptop doesn't expect its external power to sag
like a battery.  There have been laptops (well, "portables", anyway)
that were run off gell cell type batteries...

You'll probably get a fraction of the lifetime per pound of battery that
you would out of modern Li-ion batter packs, but then maybe sitting there
with with a huge suitcase full of batteries, cables strung all over, and
odd lights flashing here and there will be useful for attracting certain
types of members of the appropriate sex and gender than hang out at B&N.
It's certainly not any worse than what some people do to their cars for
similar purposes.  Personally, I find the current crop of laptops only
useful if you can find someplace to plug it it, or for really SHORT
off-grid use.  If you want battery life, consider a PDA...  Maybe things
will improve with the advent of fuel cells (any year now...), but those
will probably be "priced appropriately, given the expected run time."

Be careful not to start any fires - one of the safety features you'll be
bypassing is the careful mechanical engineering of battery packs that
prevents them from accidentally being shorted out, which can be a real
problem with the sort of total energy and current delivery capability
that you'll be needing.

 :-)
BillW

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