When you use this one battery first time, please. Push the wheel have a speed with 3-5 km/h. Otherwise the battery have protection, won’t work. 4-5 hours, less 5 hours. Charge and discharge 350-400 times. 24V: 2408075mm 36V: 2958075mm. Suitable for these model bicycleA/B/C/D. A: If the distance. B: The distance MUST >3.5cm. C: If the distance >5cm, need break a shape like the C picture shows, need carefully to choose. D: If the distance. NOTE: If you have any question can’t decide, please contact saller.