nite rider flight problems?
 

I have the flight about 2 years and the charge in the battery will not hold!(I think). After charging the battery for 1 hour the charger shows that the batt is full charged! But when i plug in the light and turn on it shows 1/2 charged! I do not know if the batt is bad or charger no good! How could i check the charger if it is putting out correct charge? I did let the batt go down to complete empty!