Laptops that I have worked on do not need the laptop to be switched on to charge the battery. There maybe a LED indicator on the laptop to indicate that the battery is charging when the power adapter is connected.
Had batterys out and charged separatley, installed and control was in green. Ran it around until it went to yellow. Put on charger and charged with power switch off for 5 hours, no change,was still in yellow when turned on.Also what does the single green lite under charger plug tell me? I got the unit from person who put new batterys in last Sept. and let it set till Feb. Batterys were completly discharged then.Does power switch need to be on, I hesitate to leave it on unless required to charge. Thanks