48v 10.4ah battery on 750w rear hub bike.
I used higher Assist a lot more in the beginning (Mar-2018), when I was 60 pounds heavier (303lbs then) and had no fitness/ stamina for sustained biking early on.
5,200 miles later, I ride almost 100% of the time in Assist Level 1 (of 5 max), and I use Level 2 sometimes for short but unpleasant hills, depending on how long I've already been riding when I encounter them
Though even some of those routine hills on my regular routes, I've taken to sucking it up and staying in Level 1, for a bit more exercise value.
In good weather I tend to max out around 30-mile-rides in a day, mostly at a leisurely pace; like yesterday. I started yesterday's 30-mile ride on a 100% new, full charge, and when I got home only 1 bar had disappeared (of 5 bars in the digital gauge. Not very scientific, I realize...) I will probably ride this existing charge cycle down to 2, or even 1 bar, remaining before recharging back to full.
So with the low-Assist riding habit I've grown into over the last year of biking, relying on gear-changing more (10-speed) I've logged 85 miles on a single charge (though I still had 2 bars on the battery gauge showing when I finished, but decided to recharge for the next day's commute.) I haven't tried that exercise since then -- so maybe I'll ride this cycle to 1 bar, just to see how many miles I can get at this point...
I ride paved surface trails almost exclusively, and some roads. Northern Virginia here, which is not at all mountainous... (for example, the highest point of land in D.C. is only 410 feet above sea level.)