About 22.8 days ago I started an experiment to see how long my Apple branded AA batteries would last when powering my Apple branded Magic Mouse. I did this more out of curiosity than anything else. My test parameters were as follows: I inserted two fully charged (according to the Apple battery charger) AA batteries into my Magic Mouse. I started up the Clock app on my iPhone. I turned on the Magic Mouse. As soon as my iMac paired with the Magic Mouse via bluetooth, I started the timer on my iPhone. I then left the mouse on and left the timer running. I waited until my Magic Mouse lost bluetooth connection with my iMac and stopped the timer. This is what I saw: 
546 hours, 27 minutes, 43 seconds – and so on. It might not be precise down to the tenth of a second, or even the second, but I think that it is accurate enough for my purposes. I now know how long, approximately, a pair of branded AA batteries lasts in my Magic Mouse. But, I grew up doing science projects in middle and high school where I was graded on my ability to design, run, and conclude rigorous experiments. One test is hardly a conclusive pseudoscientific experiment.
Well, as it so happens, I have two other AA batteries, and I have started a second test along the exact same parameters as the first. I will perform 10 tests with each set of batteries and then can cull a more exact approximation of their time before depletion. Then, to be fair, I will test two sets of two AA batteries from two leading brands (probably Duracell and Energizer) as controls to which I can compare my results.
Sounds like months of scientific fun!
You can read my original post about the batteries here.
a simple man 