My docking station stopped charging the battery for my RC5200. The voltage AC adaptor just before it enters the DS is about 15 volts. The output voltage across the DS at the two end leads is 5.7 volts. I cannot tell if the DS is operating properly because I don't know how much voltage is supposed to be across these two leads. Is the output voltage too low? The battery pack carries a voltage of 4.7 volts. Can anyone help me figure this out?

Thanks