Currently Being ModeratedDec 24, 2013 2:15 PM (in response to KeyesRM)
It's fine. It's not down at all. Your battery is fully charged to 7937 mAh which is 100% of its maximum charge. If the battery started off with 8460 mAh of maximum charge (a battery's design level, but not necessarily what your battery was because this varies from one sample to another) then the current charge level is 94% of that design level.
You are fretting over nothing given the age of the computer.
About Batteries in Modern Apple Laptops
Currently Being ModeratedDec 24, 2013 2:17 PM (in response to KeyesRM)
Doubtful Apple will not do anything until the battery fails. Along with that the battery is really only covered by any type of warranty for the first year. Apple considers the battery to be a consumable item that will fail eventually. When that is no one knows.
You can take it in and have it checked but as long as it is charging and holding a charge that is all that counts AFA Apple is concerned.
Currently Being ModeratedDec 24, 2013 2:29 PM (in response to KeyesRM)
Apple guarantees that if your battery is well taken care of and not abused, however your battery looks fine.
You state: ~ As you can see, I've only had 60 cycles on the battery
Cycle counts dont account for much. People (some) leave their macbooks always hooked on power and worse still in sleep mode and on power and this can ruin a battery in "50 cycles", ergo it means little.
As for the 5% power fluctuation this means absolutely nothing since charge is just an estimate and the 5% is within that range.
Bad discharging or battery use conditions:
Heat (due to environmental conditions or due to rapid discharges from heavy use = gaming / video editing)
Rapid discharging of the battery frequently causes chemical changes over time in the battery leading to decrease capacity and resistance of current flow.
The very worst use of your battery is often draining the battery very low, and worse still letting it remain in such a state.
*Most long-term rapid damage to the battery occurs from discharging it with high loading (gaming) conditions but paramount is avoiding deep and frequent low DOD (depths of discharge) in use.
Undesirable charging or charged conditions:
High perpetual SOC (state of charge), where the battery is always or very often connected to charge
Parasitic loading where the battery is both usually on and charging or worse both always charging and in sleep mode, since this induces mini-cycling of the battery.
Bad general handling conditions:
Temperature use conditions when either too hot (95F and above) or too cold (50F and below)
Storing your battery away with a low charge (40% and less) long-term.
Your battery is subject to chemical aging even if not in use. A Lithium battery is aging as soon as its made, regardless.
In a perfect (although impractical) situation, your lithium battery is best idealized swinging back and forth between 25 and 85% SOC (state of charge) roughly.
Further still how you discharge the battery is far more important than how it is either charged or stored short term.
Ultimately counting charge cycles is of little to no importance. Abuse in discharging (foremost), charging, and storing the battery and how it affects battery chemistry is important and not the ‘odometer’ reading, or cycle counts on the battery.
Everything boils down to battery chemistry long term, and not to an arbitrary number, or cycle count.
Keep your macbook plugged in when near a socket since in the near end of long-term life, this is beneficial to the battery.
"Apple does not recommend leaving your portable plugged in all the time."
General rule to remember of Lithium batteries is:
Never drain them LOW & dont always/often store them HIGH
While cycle count is commonly seen to be the “miles” on your Lithium Ion pack cell in your Macbook, which they are, this distinction is not a fine line at all, and it is a big misconception to “count charge cycles”
*A person who has, for example, 300 charge cycles on their battery and is recharging at say 50-60% remaining of a 100% charge has better battery usage and care than another person who has 300 charge cycles at say 15% remaining on a 100% charge.
DoD (depth of discharge) is far more important on the wear and tear on your Macbook battery than any mere charge cycle count. *There is no set “mile” or wear from a charge cycle in general OR in specific. As such, contrary to popular conception, counting cycles is not conclusive whatsoever, rather the amount of deep DoD on an averaged scale of its use and charging conditions.
(as a very rough analogy would be 20,000 hard miles put on a car vs. 80,000 good miles being something similar)
*Contrary to some myths out there, there is protection circuitry in your Macbook and therefore you cannot overcharge it when plugged in and already fully charged
*However if you don’t plan on using it for a few hours, turn it OFF (plugged in or otherwise) ..*You don’t want your Macbook both always plugged in AND in sleep mode (When portable devices are charging and in the on or sleep position, the current that is drawn through the device is called the parasitic load and will alter the dynamics of charge cycle. Battery manufacturers advise against parasitic loading because it induces mini-cycles.)
Keeping batteries connected to a charger ensures that periodic "top-ups" do very minor but continuous damage to individual cells, hence Apples recommendation above: “Apple does not recommend leaving your portable plugged in all the time”, …this is because “Li-ion degrades fastest at high state-of-charge”. This is also the same reason new Apple notebooks are packaged with 50% charges and not 100%.
LiPo (lithium polymer, same as in your Macbook) batteries do not need conditioning. However...
A lot of battery experts call the use of Lithium cells the "80% Rule" ...meaning use 80% of the charge or so, then recharge them for longer overall life.
Never let your Macbook go into shutdown and safe mode from loss of power, you can corrupt files that way, and the batteries do not like it.
The only quantified abuse seen to Lithium cells are instances when often the cells are repeatedly drained very low…. key word being "often"
The good news is that your Macbook has a safety circuit in place to insure the battery doesn’t reach too low before your Macbook will auto power-off. Bad news: if you let your Macbook protection circuitry shut down your notebook at its bottom, and you refrain from charging it for a couple days...the battery will SELF-DRAIN to zero (depending on climate and humidity)…and nothing is worse on a Lithium battery being low-discharged than self-draining down to and sitting at 0
Contrary to what some might say, Lithium batteries have an "ideal" break in period. First ten cycles or so, don't discharge down past 40% of the battery's capacity. Same way you don’t take a new car out and speed and rev the engine hard first 100 or so miles.
Proper treatment is still important. Just because LiPo batteries don’t need conditioning in general, does NOT mean they dont have an ideal use / recharge environment. Anything can be abused even if it doesn’t need conditioning.
From Apple on batteries:
Storing your MacBook
If you are going to store your MacBook away for an extended period of time, keep it in a cool location (room temperature roughly 22° C or about 72° F). Make certain you have at least a 50% charge on the internal battery of your Macbook if you plan on storing it away for a few months; recharge your battery to 50% or so every six months roughly if being stored away. If you live in a humid environment, keep your Macbook stored in its zippered case to prevent infiltration of humidity on the internals of your Macbook which could lead to corrosion.
Currently Being ModeratedDec 30, 2013 12:35 PM (in response to PlotinusVeritas)
Thank you for that info, I hadn't been able to find that before. My macbook frequently is in sleep on the charger so I'll make a point of taking it off the charger after it's been fully charged if it's sleeping. I have applecare, so the 1 year warranty doesn't really worry me, I've got 3 years of protection for this thing to get below 80% capacity, which is their guarantee. I think you're right about the cycles don't really matter thing, because I have a friend with the same model of rMBP as I have, and her battery is about at the same capacity as mine with double the cycles. She has a lot of heavy load discharges though, watching netflix with the computer on a bed, or gaming, etc., so maybe it's not a good comparison.
I have only ever gone down to 0% battery maybe three times. Certainly less than 5, and it was plugged into the charger within the hour. Most of the time when it gets below 30% I plug it in. But it does stay on the charger a long time with the computer sleeping (lid closed, not off) so that could be part of my problem. I didn't realize the power consumption in sleep mode was that significant, especially since I'm pretty sure after awhile the computer hibernates, which uses no power (same as off). But I have no idea how long it takes for it to hibernate from being in sleep mode. I just know it does because if my computer's been idle all night, it takes like 5 seconds for the screen to come up when opening the lid but from sleep it's near instant. So I would think it wouldn't be having THAT much of an effect but maybe it does. I'll keep all those things in mind. I know LiPo batteries are sensitive to heat, so I never do instensive processing (audio editing is my thing, I don't do that on battery) while on battery power, so I virtually never do fast discharges, and rarely have high DoD's. Thanks for all the info, I'm a bit more reassured and informed now.