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Battery charge/capacity/calibration question

H

hassouni

macrumors member
Original poster
Feb 10, 2008
76
0
I've had my MBP 15 since March, when the Penryns first came out. I used to get 4 hours or so unplugged, but now only get 2 hrs, running the same applications, with wireless on. This seems like a very fast drop. I downloaded Coconut Battery and it says I'm at 98% charge (when the power meter says full), with 95% capacity left, after 51 load cycles. surely 95% capacity should yield a lot more than 2 hrs?

As for the 98%, is that the maximum it will charge to? Also, how do some people increase their capacity over time, as well as have a computer for several months with only single digit battery load cycles?

Finally, for calibration, the macrumors guide says to wait till the battery is fully charged before draining it. Does that mean when the battery meter says "fully charged" or does it mean when it's at 100%... because right now it's "fully charged" but at 98%.

Thanks!
 
What is your Maximum capacity?

Apple in the upper left hand corner > About this Mac > More Info > Power

A Brand new battery should have about 5500 mAh.

So you should be at about 5390 mah. I wouldnt worry unless it is below 4000, then you should call apple and have it replaced.
 
xxMacAttackxx said:
What is your Maximum capacity?

Apple in the upper left hand corner > About this Mac > More Info > Power

A Brand new battery should have about 5500 mAh.

So you should be at about 5390 mah. I wouldnt worry unless it is below 4000, then you should call apple and have it replaced.
Click to expand...

This isn't accurate. I have 18 cycles on a 2-3 month old MBP battery (calibrated) and it shows 99% and 5085 mAh with a full charge capacity of 5113. A couple months ago, the full charge was 5573. The 5500 isn't always the capacity.
 
That sounds pretty strange, especially with such a high capacity left. I have about 94% capacity and still get well over 4 hours battery on my 15 inch 2.5ghz. There are a few things I would check if I were in that situation:

1. Make sure you're screen isn't on the highest brightness setting (you'll notice from middle to high there's a huge difference in your time remaining)
2. Check activity monitor for anything sucking CPU cycles (it might not be an obvious program, rather something you didn't notice was running, or was running inefficiently)
3. Monitor your network usage, downloading torrents and other activities that yield a high number of external connections and have data coming in constantly to the laptop drain battery much more quickly.

Anyways start there, and like the posts before me mentioned check your max capacity number as maybe you just have a faulty battery. Hope that helps!
 
ggjstudios said:
This isn't accurate. I have 18 cycles on a 2-3 month old MBP battery (calibrated) and it shows 99% and 5085 mAh with a full charge capacity of 5113. A couple months ago, the full charge was 5573. The 5500 isn't always the capacity.
Click to expand...

It varies per battery.. Notice the about in my previous statement....

The most I have ever seen is 5598 mAh....
 
xxMacAttackxx said:
It varies per battery.. Notice the about in my previous statement....

The most I have ever seen is 5598 mAh....
Click to expand...

Also, assuming she started with 5500 mAh, 95% capacity would be 5225, not 5390. The 95% is a measure of battery health (capacity to hold charge), not current charge. The OP has charged 98% of her 95% capacity.
 
She? haha, nope.

OK, so now it says:

Current battery charge: 5254 mAh
Max battery charge: 5265 mAh
99%

Current battery capacity: 5265 mAh
Original capacity: 5500 mAh
95%

When it was new, was the max charge 5500 as well, and it's now been reduced to 5265?
 
hassouni said:
When it was new, was the max charge 5500 as well, and it's now been reduced to 5265?
Click to expand...

That's assuming it started at 5500, which isn't assured. It may have started higher or lower. My battery health, according to iStat Pro, is 91%, with 5113 capacity, which would indicate it started at 5619 mAh.
 
ggjstudios said:
This isn't accurate. I have 18 cycles on a 2-3 month old MBP battery (calibrated) and it shows 99% and 5085 mAh with a full charge capacity of 5113. A couple months ago, the full charge was 5573. The 5500 isn't always the capacity.
Click to expand...

I have my MBP over year and battery shows 97% capacity, 25 cycles and 5324 mAh. Pretty good :)
 
hassouni said:
How do you keep it at such few cycles? Do you just not use it unplugged often?
Click to expand...

I'm using my MBP like desktop machine -- almost always plugged. But I leave MBP unplugged overnight. In the morning, iStat shows that charge is about 93-94%. In this way, I keep low cycles and good condition my battery. As you can see, it works!
 
So does this mean everyone with the super low cycle numbers keeps it plugged in almost constantly? I do move around with it a lot, I guess I can't avoid a lot of cycles?
 
ggjstudios said:
Also, assuming she started with 5500 mAh, 95% capacity would be 5225, not 5390. The 95% is a measure of battery health (capacity to hold charge), not current charge. The OP has charged 98% of her 95% capacity.
Click to expand...

In the OP she stated that she was at 98%, so that is what the calculation is based off of..
 
xxMacAttackxx said:
In the OP she stated that she was at 98%, so that is what the calculation is based off of..
Click to expand...

The OP wrote:

hassouni said:
... I downloaded Coconut Battery and it says I'm at 98% charge (when the power meter says full), with 95% capacity left, after 51 load cycles. surely 95% capacity should yield a lot more than 2 hrs?
...
Click to expand...


The capacity was what was being discussed.
 
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