If you have lithium ion batteries, you need to charge them. Use the P117. It works with both lithium ion and NiCad batteries, so it can work well with Ryobi models, from the P100 to the P108. Some batteries, like the P102, can be charged in as little as 30 minutes, letting you get to work as soon as possible when they’ve run low. This charger model has a special maintenance mode that keeps your batteries at peak condition after they’ve been fully charged, making sure that they don’t drain and protecting them from power surges. This system will also cease to charge at the battery’s full charge, saving energy and, subsequently, your power bill. The P117 has a temperature indicator as well. You can use this to gauge how well your batteries will function in your given workplace. This is a heavy duty charger for heavy duty Ryobi users. You will not be disappointed with its performance.