INSANE (well, kind of) Battery Health Fluctuation

[asherman13]

Hey all,

So, my MBP was charged this morning, and, AFAIK, had its usual 96%-97% battery health. I used it during one class, while plugged in, and then opened it twice on battery power (once to see if I could connect to the wireless network on campus for about 3 minutes, and once to try and send something on a computer-to-computer network; that time I didn't even enter my password into the "wake from sleep" password dialogue before I closed my MBP).

Looking at it (it is now charging up from its roughly 1-2% battery loss from those times and from being asleep for a few hours), the battery health is now 88% (4863 mAh of 5500 mAh, according to both Coconut Battery and Apple System Profiler). I've had it fluctuate before, down to about 92%, when I was using it on battery power a lot and recharging it frequently, but it always bounced back up after a night of being plugged in; as of this morning, I hadn't used it on battery power for about 5 days, and doing so in the past has never caused a problem.

I'm going to let it charge and everything overnight, hopefully that'll bring the health back up.

Your thoughts?

 

[Reach]

I'm just testing my battery after doing the initial calibration (Charging, resting, using all, resting, the recharge.) and CoconutBattery now says I have a capaity og 6833... Original capacity says 5500, so I don't know what's up with this. Last time it kept on charging for a long time on 99%, didn't stop, so I took it off power and used it a bit, now on my way back up again, current charge now is 6400 and it says 93%, so I'm wondering if it actually stops charging when it reaches 100% this time, so I get the green indicator on my magsafe.
Does this sound normal? (I have a 17" C2D, anyone else done coconutbattery? Whats your capacity?)

 

[asherman13]

I'm just testing my battery after doing the initial calibration (Charging, resting, using all, resting, the recharge.) and CoconutBattery now says I have a capaity og 6833... Original capacity says 5500, so I don't know what's up with this. Last time it kept on charging for a long time on 99%, didn't stop, so I took it off power and used it a bit, now on my way back up again, current charge now is 6400 and it says 93%, so I'm wondering if it actually stops charging when it reaches 100% this time, so I get the green indicator on my magsafe.
Does this sound normal? (I have a 17" C2D, anyone else done coconutbattery? Whats your capacity?)

I don't know about this whole "charging, resting, using all, resting, the recharge" thing; all you have to do to calibrate is charge it all the way up, use it ALL the way down, wait 5+ hours, then recharge (I guess the first "resting" confuses me...).

As for the charging to 99% and all, wait until the indicator light on your MagSafe charger turns green. Even though your battery power thing might say you have 99% or whatever, your battery IS charged to its maximum capacity, no matter what. The indicator light is what you should believe in this case.

If you go into the Apple System Profiler (Apple menu>About This Mac, click "More Info..."), and then click on the "Power" menu (under "Hardware"), you can see the "Charge Capacity" information. I don't know how many mAh 17" C2D batteries start out with, however, it's probably more than 5500mAh, for the sole reason that the 17"-ers use a bigger/more powerful battery (I think) than the 15"-ers, the C2D factor being excluded. CoconutBattery is probably using 15" battery statistics.

My advice: Charge your MBP until the indicator light is green (also, your battery thing in the menubar should say "(Charged)" rather than "Calculating..." or any amount of time left until your battery is charged; you must have the "Time" option selected to view this), and then look in the System Profiler to see what your base mAh should be for your battery. Then, save that information in CoconutBattery's expandable "Saved Information" area thing.

Hope that helps!

EDIT The 17" C2D MBP's use a 68-watt battery, while the 15" C2D MBP's use a 60-watt battery.

EDITx2 Looks like I was wrong; apparently you're supposed to let your battery rest for 2 hours once you charge it up initially.

 

[Reach]

Thanks, it's green now, at 6833 mAh, so all is good.
The first "resting" was just that I was supposed to let it stay at full capacity with power connected for a couple hours before I used it all the way down.