All Ryobi batteries are shipped with low charge levels, so they should be charged fully before inserting the battery in a tool. The Ryobi charger is designed to charge only lithium-ion and nickel-cadmium batteries. In addition, those batteries must be Ryobi batteries. The charger will plug into any outlet that is of normal household voltage, or 120 volts. The charger comes with two LED lights that indicate the state of the battery and its charge level.
Plug the power cord on the Ryobi battery charger into the power outlet. Make sure the charger is in a location that is room temperature, or between 50 and 100 degrees Fahrenheit.
Insert either a Ryobi Lithium-ion or Nickel-cadmium 18-volt battery pack into the charger. Align the raised rib side of the battery with the groove in the charger. The contacts on the battery pack must face the contacts on the charger. Make sure the latches on each side of the battery pack snap into place and the battery is secure in the charger.
Press down on the battery to ensure the contacts engage with each other.
Allow the battery pack to charge. The battery will become slightly warm to the touch – this is normal.
Look at the LED light. When the green LED light is flashing and the red LED light is steady, the battery is charging. When the red LED is off and the green LED is steady, the battery is fully charged. If the red LED light is flashing and the green LED light is off, the battery is being tested: This could occur if the battery pack is initially too hot or cold when placed in the charger. When both LED lights are flashing, the battery is defective.