Instructions
Charge the controller fully before using the first time. Charging the battery completely starts the battery off right, which allows it to receive a full charge cycle to test the limits of its batteries immediately.
Charge the controller only after it is completely dead. The batteries in the PS3 controller are not built for frequent charging. They are made to be charged completely only after the current charge has been completely used on it.
Charge the controller only when you are not using it. It may be tempting to keep a controller plugged in while you are playing a game, but you can easily lose track of its current charge doing it that away. Additionally, the power is split from the console and controller, keeping the batteries from receiving an adequate charge.