CSC FT1000md -- Range?

[ibMax]

I recently bought a CSC FT1000md, they advertise the range being up to 75 miles if used conservatively in eco mode, with you doing most of the work. I have tried this and I'm only getting 18 to 20 miles by the time my battery is down to 10% . I've have tried everything short of turning it off completely..., and 18 to 20 miles is all I can seem get out of it.______ Any suggestions??? TIA