I ride an SL4 EQ with an RE. I’ve been less energetic this year than in the past. Maybe being 75 has something to do with it? This means I use Sport and Turbo mode more often. (35/35, 45/80, 100/100)
Anyhow, most of my rides are on a rail trail - long shallow hills - and less than 400 feet of accent - and about 20-30 miles.
I get at least three rides per charge. That means I have about 25-30% charge left when I plug in. So, I get between 60 and 80 miles most of the time. I suspect I could do a century on the right route and weather.
I‘ve never ridden long enough to get below 15% with one exception. I had organized a 40 mile ride for my ebike group. My bike was down to about 25% the day before the ride and thought I’d plugged it in. Nope. I rode to the starting point - about 4 miles - and left the bike powered on while we all gathered. About 5 miles into the ride my batteries got below 5% and gave out. Did the remaining 35 miles without assist. SL!
That was two years ago. I don’t think I could ride that far without assist today.