Hi IrisMarie.
When charging your wheelchair the wheelchair should be turned off. When you plug your wheelchair into the battery charger there should be an on switch on your battery charger.
Always waiting until the battery is very low before you charge them is not a good idea. It will shorten the life of the batteries.
No, all the led lights should not be green. From your description it appears that your chair's led should have 3 colors.
The LED lights indicate how much battery "charge" you have. The led colors: all 4 green led lights = fully charged; green led indicates good, orange = caution and red = warning/danger very low battery. As you use your wheelchair the LED lights will change declining from the highest green down to orange and then down to red. For example as you use up the battery charge you will no longer see any green lights, only orange and red. When the battery is very low you will not see any green or orange lights only red. We charge the wheelchair overnight when the LED reaches the highest orange light/bar (have had the same batteries for 5 years now) However, depending on how much you use your chair and how old your battery is you may want to charge it more often. If you do not use your wheelchair for any length of time you will still need to make sure it is kept charged on a regular basis or the batteries will die.
Did you receive an owner's manual with your wheelchair? If not you might want to call or email the manufacturer to send you the manual. You also might be able to get the manual from the manufacturers web site. We have found our manual to be an excellent resource for maintaining and troubleshooting.
Hope this is helpful.
By the way, I love reading your posts. You are such a sweet, endearing, funny woman.
Vicki
Husband DX 11/1997