My MacBook's battery indicator doesn't seem to be working as it should, nor is it accurate. I was trying to caliberate my battery recently and was running it down until I see the low battery warning, except that I never did get to see said warning, because at around 45% as shown in the menu bar, my screen just went off and the machine apparently went to sleep. I proceeded to leave it alone for the mandatory 5 or more hours before resuming charging to find that the indicator now shows that battery is indeed drained to 0%. Any idea what I could do to rectify the problem? This can get annoying because I have no warning as to when I should be saving my work and closing applications before I run out of battery power.