JP>    We can see the demise of this upstairs Air in a very close
 JP> future, the battery is not holding its charge very long now, it
 JP> does not run a full day. The user will not be bothered using it
 JP> tethered to the grid !

the user needs to be trained in the special care and needs of batteries...
that battery is replacable, isn't it? if yes, i'd get two and swap them
when the one being used is completely depleted... battery conditioning is a
necessary skill that all too many don't know or learn... i've seen way too
many devices thrown away because they didn't take care of the battery or
even think to replace it... instead they'd rather spend several hundred $$$
for a new device 

)\/(ark