How to check the number of battery cycles of a laptop?

1. Open system overview (called system information in 10.7 system), which can be opened in the folder of Applications = Utilities.

2. In the list, select Power Supply.

3. Find "cycle time" in "efficiency information".

4. Now, you can check the battery cycle time of your Mac.

5. The number of battery cycles is the number of times you consume the battery to 0% at a time and then fully charge the battery to 100%. Note: the number of battery cycles is not the number of times to guide you to plug in the power every time.