The battery is charged but the lights just flash and chair doesn't move

Make sure the charger is unplugged from the chair and that the chair is in gear. There's two levers that place the chair in freewheel, or neutral so you can roll it around. Place these in neutral, then back in gear firmly. If still flashing, turn chair off, wait three seconds and turn back on, then push on the horn button three times. This will take it out of sleep mode. Still not going, you will need to check all clip-on connections to make sure they are tight.

I am assuming that all of the lights are flashing constantly. If it flashes a "fault code", you will get a series of flashes from 1 to 10, then a pause, then a set of flashes. Count the number of flashes and it will tell you what the fault is for that number of flashes in the owners manual. If it is just two red lights flashing constantly, you have a set of dead batteries.

Good luck.