how iphone app Battery Log works?

Question

I did some research and found that there is a log in the /private/var/ in which we can get the battery log. But unfortunately the iphone apps doesn't have read access to that file.

So I was wondering how the "Battery Log" works? (Battery Log is a app in the app store. It can display the battery history usage)

Answer 1

In the application description it says that the application only gathers data when it is launched (which makes sense given the restrictions apple puts on apps and - as you mention - the Battery log file is private). The app description also states that the app only works on a relative basis and cant get exact voltage. Beyond that it seems like some black magic.