One has to wonder why Segway has stuck with Valence for so long. The problem with Valence is that their batteries have always been too expensive. I don't know how much Segway pays for Valence batteries, but they charge their customers over $2,000 per kWh for replacement batteries. Automotive traction batteries reportedly cost around $500 to $600 per kWh and are moving toward $250 per kWh, according to this article.
http://www.greencarreports.com/news/...alyst-says-yes
After all these years, Segway remains Valence's largest customer. Given that Segway isn't a very large customer, Valence has never been able to achieve sufficient volume to generate economies of scale. One would think that Segway would have looked for a lower-cost supplier by now.