I couldn't get your link, some DNS issue.
The problem with computing something how long the battery will last is the load.
While the motor may draw 35.6 at it's max output, it is unlikely to do max load all the time.
Existing products, like this one, with 24v 4.5AH battery claim 5-7 miles on a charge.
That is roughly the energy content of a 24v power tool battery. You could carry more than one.