The Battery is very important.
I recommend a minimum 48v 15ah battery.
You need to go mimimum 20 miles so to be safe you'll want 15ah or highe for distance and 48v and higher for speed.
I get 30 miles out of mine pedaling and conserving.
Flat out throttle on max I believe that I get a little over 20 miles but haven't tested it out yet.
I weigh 265Lb and am on a mountain bike with thick tires.
Good luck.