Lights turn on cant move

Do you get any flashes from the controller lights? This is usually the way you diagnose errors. A high number of flashes/beeps often means there is an issue with the controller or joystick.
Batteries are only fitted if they are needed so a 'spare' battery isn't very likely. Most wheel chairs and scooters need a powerful battery to spin the electric motor so a pair of batteries are used. The two batteries also act as a counter weight to keep the chair upright.
They are normally fitted in a 'serial' or 'in-line' set up. Basically into one battery, across to the second battery then out through the second battery.

If the charger is unplugged and the freewheel levers are in drive position. The joystick should not have any flash lights on it, this indicates a flash code that needs to be addressed. If the lights are rippling up and down it could be locked out. some joysticks can be reset by pushing the horn button twice after turning it on within 10 sec.some are reset by pushing joystick forward until it beeps then back til it beeps this done right after startup also. otherwise there maybe something more serious going on with the chair. Strege Mobility

I’m happy to assist further over the phone at https://www.6ya.com/expert/bill_bcbb89783b08c489

The freewheel lever isn't re-engaged properly. Try moving the lever to "free" then back to "drive" again. The lever moves a small micro-switch.

Press and hold power button til beep then push joystick forward and hold joystick til beep then pull the joystick back and hold joystick til beeps. turn power off then on. should be unlocked now

The pattern of lights and beeps should tell you what the problem is. The chart is in the manual. You can download one if needed.

Not much info to go on, but you may be in Lock Mode. On a VSI the Profile LEDs scroll left to right.To Unlock a VSI: Push joystick forward until beep, then pull joystick back until beep. Unit is now unlocked.

make sure the motors are not disengaged, turn off chair, can you move it by pushing it? if so lock the wheels and try again. next is the controller in lockout. press and hold the on button till it beeps push joystick forward til it beeps pull it back til it beeps turn off try again. you can call 1-800-800-8586 for tech support

Move the freewheel levers back and forth so the chair does not move drive position

I’m happy to assist further over the phone at https://www.6ya.com/expert/bill_bcbb89783b08c489

chair is locked out. turn on then push joystick forward till it beeps then pull backward till it beeps then it is unlocked

The chair is in lock mode. To unlock, turn on, when the lights start to scroll, push the joystick forward and keep it there until you hear the beep. When it beeps, pull it back and wait for the beep, once the beep sounds let go and listen, if you hear a high pitch beep, success. If it doesn't work the first time, just do it again. Sometimes it may not work right away but don't panic, just follow the steps again.