I get a little under the advertised range on my RadRover 4" fat tire bike of +20 miles at 20 mph for a max 180 lbs rider (60 lbs bike, 48 volts/15 amps/22 amps peak, 11.6 Ah, 750 watt rear hub motor).
I use it mostly to commute to work around 13 miles round trip, 4900-5400 ft elevation range, I'm about 270 lbs, and the bike+gear around 75-80 lbs. I have it on the highest PAS (level 5, 20 mph max) and use most of my wattage in the afternoon since it is 70% uphill. I try to pedal as much/hard/fast as I can to keep the power around 150-300 watts. The combo of the extra weight and steady 4 mile incline zap about 10-15% of my range at the highest PAS level. I might only be at a 1-5% loss if I drop the PAS to 2-3; but, I don't want to spend more time in traffic at a slower pace just to save 1-2 cents of power.
I did take the RadRover on a endurance run last weekend (PAS level 3, 12-14 mph, power levels 50-150 watts of assisted power, flat terrain). I was able to go 36 miles in 3 hours before my legs just got too tired. I still had one solid bar left (blinking bar means almost depleted). I think I could have broken the 40-45 mile mark on level ground (last 4 miles was the 500 ft elevation climb uphill to my house).