My Hoveround MPV5 batteries will not charge, do you think it is a battery problem or a charger problem?

If you plug the charger into the wall, turn on the power switch and the light comes on, the charger should be working properly. Here is a way to test it-
Attach the charger that came with the power chair to the power chair controller firmly and turn the power chair on, while the charger is running. What should happen:the lights on the controller will scroll back and forth. If this does NOT happen and you can confirm the charger is turned on, the charger handle is fully seated inside the controller receptacle and the wall outlet has power, then the charger may have a problem and needs to be replaced.

If the charger is OK, then there may be a problem with the batteries. Here are some sypmtoms:
1-You connect the charger but the light on the charger never goes red, it just stays green.
2-You connect the charger but the light goes from red to green VERY fast.
3-The charger light goes from red to green but when you disconnect the charger and press the power button on the controller, you only have one flashing red light, or the batteries drain within just a few minutes of use.
4-The power chair has been stored or sitting idle for several months.
5- The power chair has been connected to the charger 24-7 for several months.
Any of the above examples indicates that the batteries are oxidized or damaged and will most likely need to be replaced. The MPV5 takes two, U1 12 volt 33 amp batteries which can be purchased at any battery warehouse store like Interstate Batteries or Batteries Plus.
Good luck!

I plugged my chair in it only flashes one red light and when I use it. It has hardly any power help