I rented an ST2 for my girlfriend and we did a great ride today. She's less confident on these bikes so we mostly took it easy, often riding just 25 or 30 km/hr. We did 65km and had about 40% power left, and we did go faster using level 3 in some places, so it seems like you can easily do 100km on one charge if you keep it in power setting 2 and ride smoothly below 30km/hr.