I just got my brand new, 13" MacBook Pro on Friday night. Friday night and Saturday morning it was plugged in to get it all setup and all my files transferred. In the afternoon, I took it off the charger and it said i was going to get 5 hours of life, I researched a bit and found out how to calibrate the battery, which I did last night and plugged it in again this morning. I'm now in a coffee shop, first time with my MacBook on battery since calibrating it, and the time its supposed to last, is jumping wildly. Right now its says 8:55, but 2 seconds ago it was 6:08, and in the last 5 minutes its jumped as low at 5:32, and as high as 9:13, oh I lied, it just jumped to 9:49 as I was typing this. I used coconut battery and it says 2 cycles and 5850 mAh, 4 weeks old. Why is it jumping so much? I did the calibration according to Apple's guide. Waited for it to go to go into reserve and then sleep, and then left it for 8 hours while I slept, and when it restarted this morning it said "1%" battery. I don't know what the issue is. My old white macbook jumped but usually a matter of 5-10 minutes, not hours.