DIAGNOSIS A green light on the charger means it does not detect a battery load. The issue is usually the charging port on the scooter or the internal fuse.
FIX First, check the charging port for debris. Shine a light inside. Use a plastic toothpick to gently clear any packed dirt or metal shavings. Do not use metal. Try charging again.
IF THAT DIDN'T WORK The internal DC charging fuse may be blown. It's on the Battery Management System (BMS) board inside the deck. This requires opening the deck to inspect. You need a 5A 125V DC fuse, same as the Ninebot Max G30.
HEADS UP Opening the deck voids the warranty. If under warranty, contact Segway. If you open it, disconnect the main battery connector before touching any internal components. The battery voltage is dangerous.