🚀 go-pugleaf

John DeArmond pointed out, quite correctly, that my solar panel
suggestion is of the wrong scale for powering a wheelchair.  I probably
should have clarified -- using solar would be pointless without a
"real" charger as well.... but it is a not-insignificant trickle that
could significantly extend range when outdoors.  On my bicycle, I have
a 72-watt array plus two isolated 10-watt panels --- almost 8 amps
worth of 12 volts (actually about 7 of a higher voltage for charging).
  The cost/performance ratio is dubious and it takes up a lot of 
space for a wheelchair, but still... I'll wager there's someone out
there who could take advantage of this approach (coupled, of course,
with a line cord and traditional charger).
   Cheers...
  Steven K. Roberts, Nomadic Research Labs