Use only the original charger, charge on a hard floor away from exits and anything flammable, stay nearby, and unplug it when it's full. Never charge a scooter that's wet, damaged, swollen or smells.
Scooter batteries sit inside the deck, where bumps, drops and water can damage them. A few charging habits make a big difference to safety, and they also help the battery last longer.
Step-by-step checklist
Work from the top. Steps go from free and easy to shop jobs. Switch the scooter off before touching any connector. Tick each step as you go. Your progress is saved on this device.
When it's time for a shop: if you've worked through every step and the problem is still there, take the bike to an e-bike shop. Bring your notes on when it happens, plus the code.