I am pleased to announce that I have started production of a nib switch pen powered by an AAA battery. (AAA have a life measured in mAh of 1000+, the smaller watch style batteries are often less than 50.

David Fountain
http://www.irpens.co.ukThe newest pen now keeps the LED assembly in the pen when you change the battery. A nib switch is essential for adopting a natural writing style, when you put the pen on the board the LED comes on when you lift it off the LED turns off. We also sell manual switch pens but younger children find the extra requirement to hold the button down while they write and then remembering to lift off the button when they finish a little more difficult than with the nib switch version.
Or for the flash version:
http://www.irpens.co.uk/video/nib.swf