You may find that SLA provides an adequate range if you're willing to pedal. I live in the Rockies of Montana, west of Glacier National Park. I installed my Currie conversion kit last summer and have not had problems traveling 25 miles with 1 SLA battery (still had juice left in the battery when I got home). However, I pedal and reserve power assist for steep hills. I'm planning on building my own 24V 20AH LIFEPO4 with the 4-cell packs from Elite Power Solutions. I've been dragging my feet because I've been torn between LIFEPO4, which is safer, and the high C value of the more dangerous LiPoly batteries. The delay has worked to my advantage because Elite is now offering free shipping for orders placed online.