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MVallee

macrumors 6502a
Original poster
Feb 8, 2007
810
183
Ontario, Canada
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.
 
It changes depending on what programs are running and how much the system is being used. Like it will tell you that the battery will last longer if you are just text editing in word than say when you are watching a movie.
 
All I'm doing is surfing on Safari, not even watching any videos, no other programs open. Right now, says 4:49 minutes, just said 10:20 before that.
 
You should be looking at battery percentage left. Looking at "estimated" time, which as you have noticed will fluctuate wildly, is a waste of time. There is nothing wrong with your computer.

As I type this, I have fluctuated between 5:28 left to 3:25 left, just by opening google earth (my screen is at full brightness as well). Once it was closed I jumped back up to 4:26. Dimming my screen brought me up to over 6 hours.

Meanwhile, my battery percentage has stayed constant at 99%.
 
But this never happened on my old white MacBook, and both are running Snow Leopard. Shouldn't Apple have a more accurate way of estimating the remaining time? Every time I touch the trackpad the time remaining should not plummet. What's the point in even giving a time if its so inaccurate?
 
But this never happened on my old white MacBook, and both are running Snow Leopard. Shouldn't Apple have a more accurate way of estimating the remaining time? Every time I touch the trackpad the time remaining should not plummet. What's the point in even giving a time if its so inaccurate?
i think you have it the wrong way around - i think they are being TOO accurate. ;)
 
But this never happened on my old white MacBook, and both are running Snow Leopard. Shouldn't Apple have a more accurate way of estimating the remaining time? Every time I touch the trackpad the time remaining should not plummet. What's the point in even giving a time if its so inaccurate?

If you change the battery icon from time to percentage, does the percentage change wildly? If not, there isn't a problem.
 
The percentage seems to be holding steady no matter what I'm doing. I just find it odd that from one mac to another, I could have such a different experience with the estimated time remaining. You'd think Apple would have set the estimate to be a little less sensitive. I can touch the trackpad for a moment and seemingly loose 4 hours of battery life. I suppose I'll use the percentage indicator from now on and just guess myself how long I have left.
 
The percentage seems to be holding steady no matter what I'm doing. I just find it odd that from one mac to another, I could have such a different experience with the estimated time remaining. You'd think Apple would have set the estimate to be a little less sensitive. I can touch the trackpad for a moment and seemingly loose 4 hours of battery life. I suppose I'll use the percentage indicator from now on and just guess myself how long I have left.

why not use iStat Pro or something similar? i think they judge their own estimates using their own algorithms?

losing 4 hours may be beause the brightness of the screen has to turn on. the screen chews heaps of power :(
 
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