Question: ryobi how to charge battery?
Answer: Plug the power cord on the Ryobi battery charger into the power outlet. ... 
Insert either a Ryobi Lithium-ion or Nickel-cadmium 18-volt battery pack into the charger. ... 
Press down on the battery to ensure the contacts engage with each other.
Allow the battery pack to charge. ... 
Look at the LED light.