Is it possible to modify when the "Low Battery" sign appears on a MacBook with Snow Leopard? For example, currently, it warns you about a low battery when it hits 10% of the overall battery charge. What if I want to set it to alert me on 15% or on 20%? How do I do that?
There is no way of changing the internal notifications. The only thing you can do is create your own new ones.
This code when run will check the current charge of the battery and prompt you if it's under 20%. You would have to run this script at small intervals for it to work properly.