coconutBattery is a really simple, small utility for Mac OS X that keeps track of your battery status for you, so you know by how much your battery capacity has diminished since you got your machine, and the current charge status of the battery too.
The download of the coconutBattery application itself is less than a megabyte in size (823kb to be precise), and it will simply unzip itself upon being downloaded, so you can drag and drop the application icon in to your applications folder.
When you open it, you’ll be presented with a simple grey window with a few facts and figures about your battery. The top pane shows the current charge on your battery, compared with the maximum battery charge possible. This is quite interesting, because on my machine, coconutBattery reported that my battery was only 95% charged, when OS X insisted that it was ‘fully charged’.
In the second pane, you can see what the current capacity of your battery is, compared to what the original capacity was when you first bought your machine. If you own an old Powerbook or Macbook Pro, this may be quite a depressing sight, but I was pleasantly surprised to see that my 18 month old machine was still kicking with 94% of its original battery capacity after 294 loadcycles.
coconutBattery is quite an interesting application to have at hand if you want to check on the status of your battery, and can be downloaded for free from coconut-flavour.