With a 52v, 18.5ah battery from Cellman, on a regular mountain bike, motor kit from hyena.
After doing my first 1500km, I've learnt the following about my ebike.
If you ride it as a bike with assist you get a LOT more range than riding it like a electrically operated vehicle with pedalling. One way is where you get the motor to assist you in the hard bits, the other is where you assist the motor
Things that use the the most power:-
Accelerating from a stop
From a dead stop, pedal up to at least 15-20kmh before hitting the throttle
Accelerating from any one speed to another
If you are going at 25km/hr and need to speed to 35-40kmh, shift down a gear and pedal up to the speed, then match the throttle to the speed.
Going up hills
You need the most power up hills. So shift down a couple of gears, push up the throttle to give you a boost so it doesn't kill your legs.
Cruising above 40km/h
Even with pedalling, above 40km/h(~25mph), the power requirements from the motor is around 2-2.5x that at 22mph.
Full suspension
This is tricky. Without full suspension you can't go much above 18mph without your butt hurting (on london,uk streets). But with suspension you can go a lot faster but it uses more energy.
I do a daily 38km commute where I'm primarily a cyclist in start/stop traffic, and I get around 1.6Ah (95Wh) for 38km. That's with the above techniques; speed never goes about 35kmh as there's a traffic light every 200m (2.5-4Wh/km)
Outside London where there are fewer traffic lights/longer stretches without stopping, I can go at 40kmh using 300W and pedalling, giving me 5-8Wh/km.