Seeking Advice on Battery Performance Issues with My E-Scooter?

[sharpdear]

Hello everyone,

I’m new to the forum and recently purchased a used electric scooter (model: Niu NQi Sport). I've noticed that the battery drains unusually fast—sometimes dropping from 80% to 30% within just 10 km of city riding. I’ve checked the tire pressure and ride mostly in eco mode, but the issue persists. Before I consider replacing the battery, I wanted to ask: could this be a BMS (Battery Management System) issue or possibly a calibration error? Has anyone else experienced something similar? Any tips or tools you recommend for testing battery health would be appreciated. Thanks in advance for your help!