Adding to Rhapsodies Fire's advice, try removing the battery from the charger, unplugging it, then plug it back in. The lights should be green whilst empty. Then go ahead and insert your battery, and the light should immediately turn to Red, even if it was fully charged recently. At least from there you can determine if the charger is functioning properly.
The longest I have ever had an 18650 on the charge is 3 3/4 hours, that was after I had completely depleted it. If you have a Harbor Freight Tools near you, they sell a good little digital multimeter for $10. The other hardware stores sell the digitals for much more $30-$140, and the only ones under $20 are the old school tach style meters, but they still work good.