What's your market? If it's the US, there's certainly a need for longer travel distances between charging cycles. Most EV's don't have enough charge to allow for commuting to and from work yet. Especially when you factor in grabbing groceries, taking errands, or other things. I'm not sure what the right amount of range should be, but it feels like it needs to be around 150 miles or so to allow for a comfortable buffer.

Here's the census data from 2009 where they did a study on commuting in the US: https://www.census.gov/prod/2011pubs/acs-15.pdf It's pretty thorough.