Range is a very complex subject.
It's not just battery capacity. There's mid drive vs hub, inherent motor efficiency, tires (type and pressure), riding position, quality of components, air temperature etc.
EBike brands use different methodologies. One uses a "120 pound man travelling at a steady 12 mph on a flat surface". This is so far removed from reality as to be absurd.
Others won't quote their methodology, or use a vague "x amount of energy per mile" calculation. Also useless and no point in comparing to the 120 pound man scenario.
There are some truths we can take to be self evident though. For example mid drives are more efficient in stop/start & hilly areas than hub drives. Internally geared motors that spin faster are more efficient. A bigger battery goes further. Hard tail goes further than rear suspension.
We can look at manufacturers' efficiency ratings. Bosch claims a 'round trip' (from wall to kinetic energy) of 92-95%. Brose claims about 89. No one else says much.
I think there's only one way to do it: have the same 200 pound person ride at approx 18 miles per hour on the same circuit (which will be from Tarrytown to the Frying Pan
boat in NYC (West 28th St) on the South Yonkers trailway and the Hudson River Greenway and back), with the same tire pressure, for a given trip of approx 62 miles - of which 56 are traffic free - then do laps of somewhere nearby until they run out of juice. Then record the grand total and average speed.
Each bike can then be compared with some accuracy. This will start in the spring. (It's all just an excuse to have repeat boozy lunches in NYC then cycle back to work - genius!!)
Here is some solid data from years gone by: A Specialized Turbo S, non geared rear hub, with a 504 WH battery can do 16 miles in full Turbo mode at approx 25 mph before it drops to forced Eco mode at 20% power. That's about 35 minutes riding. It then has about 6 miles left. That same bike will do 50 miles on a charge at a dawdling 15 mph or so.
A Faraday Cortland S with a geared hub and a 306 Watt Hour battery can do 16 miles in full speed mode at about 19.5 mph on a charge.
A Bulls Outlaw with an internally geared rear hub & a 675 WH battery can do about 33 miles on hilly trails at approx 23 mph. Which is pretty impressive in my book.
A Bulls Lacuba with a Brose drive (mid drive, 650 Watt Hours) can do 65 miles with a 200 pound rider not breaking into much of a sweat at 18 mph on the Tarrytown/NYC/Tarrytown route. Which is pretty amazing.
A Bafang 750 Watt mid drive with a 700 WH battery on street tires can do about 46 miles at about 21 mph. Not so efficient...
More to follow!