BatteryExpert is a battery analysis tool for Mac. It allows you to view data about your laptop's battery so that you can examine its overall health state. This application by itself will not increase your battery life, but it does give you the right tools to determine when there might be a problem, so that you can fix it.
The main window is divided into three tabs: Overview, Health and Details. The first one shows the current state of your battery. It tells you whether your Mac is plugged in and the remaining capacity of the battery, along with the power draw if it is unplugged or the charge rate if it is plugged in. It also shows the average current and the current being drawn at the moment of measurement, the voltage and the current and average power. The Health tab deals more with the health of your battery over time. Here, you can calculate how much your battery has degraded since it came out of the factory line by analyzing the cycles that your battery has and the current charge capacity and the capacity your battery was designed for. Lastly, in the Details tab, you will see information about the battery like device name, manufacturer, serial number, machine model, etc.
In short, BatteryExpert is a nice tool that displays useful information in an organized fashion.