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Is it bad to keep plugging and charging my MBA all day?
- Thread starter Cjshino
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If you have access to AC power, there's no reason to run on battery. Run on battery whenever you need to and plug it in whenever you can. You can plug or unplug any time you need to, regardless of the charged percentage, and you never need to completely drain your battery. Just make sure you don't run on AC power exclusively, as your battery needs to be used regularly to stay healthy. The link below should answer most, if not all, of your battery/charging questions. If you haven't already done so, I highly recommend you take the time to read it.
Will keeping your computer plugged at all times effect how long it lasts?
I have heard the same with cell phones, that you don't want to keep them plugged in while the battery is fully charged.
It doesn't harm your Mac battery to leave it plugged in after it's fully charged. When the battery is full, it stops charging. It cannot overcharge. What is harmful is to run on AC power exclusively, as the battery needs to be used regularly to stay healthy. Read the Battery FAQ I posted earlier for more details and tips on how to properly care for your battery.
Leaving a laptop plugged in 100% of the time is in fact bad for the battery. As you correctly stated, this is not because the battery will "over-charge", but because lithium-ion batteries require regular use to maintain their health.
So you can leave your MBA plugged in when the battery is fully charged, just make sure to unplug it regularly to exercise the battery to keep it in good form. If you use your notebook daily, I would recommend that you run it on battery power for at least half an hour, once a day.
I never use mine plugged in once it's fully charged. My 4 yr old Macbook Pro is on 1107 cycles and battery at 93%. (I did the same with my old g4 Powerbook and that was still going strong when it retired after 4 years).
There's absolutely no benefit in unplugging once fully charged, unless you need to be mobile.
Any rechargeable battery needs to be once in a while drained completely and charged again to maintain its health. I know people are averse to adding one charge cycle by doing that. But its actually good for your battery health and will increase its longevity.
In fact the manual for the iPhone recommends that procedure.
That is false. It's not good for Mac batteries to be fully drained.
Macs are not iPhones.
From Apple website,
http://support.apple.com/kb/HT1490
The battery has an internal microprocessor that provides an estimate of the amount of energy in the battery as it charges and discharges. The battery needs to be recalibrated from time to time to keep the onscreen battery time and percent display accurate and to keep the battery operating at maximum efficiency. You should perform this procedure when you first use your computer and then every few months after that. If you normally leave your Apple portable computer connected to AC power and very rarely use it on battery power you may want to perform this process once a month. The website http://www.apple.com/batteries has more helpful information regarding batteries and offers an iCal calendar to remind you to calibrate your battery.
Note: If you're not sure which model your portable computer is, use these links to identify your iBook, PowerBook, MacBook, MacBook Air, or MacBook Pro.
Portables with built-in batteries
Current Apple portable computer batteries are pre-calibrated and do not require the calibration procedure outlined in this article. These computers use batteries that should be replaced only by an Apple Authorized Service Provider.
MacBook
MacBook (13-inch, Late 2009) and later
MacBook Air
MacBook Air, all versions
MacBook Pro
MacBook Pro (Retina, 13-inch, Late 2012)
MacBook Pro (Retina, Mid 2012)
MacBook Pro (13-inch, Mid 2009) and later
MacBook Pro (15-inch, Mid 2009) and later
MacBook Pro (17-inch, Early 2009) and later
Portables with removable batteries
iBooks and PowerBook G4s other than the PowerBook G4 (15-inch Double-Layer SD)
Plug the power adapter in and fully charge your computer's battery until the battery indicator lights turn off and the adapter plug light goes from amber to green, which indicates that the battery is fully charged.
Disconnect the power adapter and use your iBook or PowerBook. When your battery gets low, you will see the low battery warning dialog on the screen. Continue to use your computer until it goes to sleep. At that point the battery has been sufficiently drained for calibration.
Connect the power adapter and leave it connected until the battery is fully charged again.
Another one from Apple,
http://www.apple.com/batteries/notebooks.html
Apple recommends charging and discharging its battery at least once per month.
And one more thing... iPhone battery did not come from an alien planet, its just another rechargeable battery.
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Did you read the full scope of the article or only skim through the parts that you highlighted?
From the article you quoted:
"Portables with built-in batteries
Current Apple portable computer batteries are pre-calibrated and do not require the calibration procedure outlined in this article. These computers use batteries that should be replaced only by an Apple Authorized Service Provider.
MacBook
MacBook (13-inch, Late 2009) and later
MacBook Air
MacBook Air, all versions
MacBook Pro
MacBook Pro (Retina, 13-inch, Late 2012)
MacBook Pro (Retina, Mid 2012)
MacBook Pro (13-inch, Mid 2009) and later
MacBook Pro (15-inch, Mid 2009) and later
MacBook Pro (17-inch, Early 2009) and later
Basically any modern Macbook does not need the CALIBRATION to be done.
Note that I put calibration in caps.
"The battery has an internal microprocessor that provides an estimate of the amount of energy in the battery as it charges and discharges. The battery needs to be recalibrated from time to time to keep the onscreen battery time and percent display accurate and to keep the battery operating at maximum efficiency."
They are telling you that the calibration process affects the microprocessor inside the battery that tells the computer how much charge is left. In other words the calibration is to calibrate your battery gauge and in turn giving you the best measurement of battery to ensure you use it to the max. This was especially true of older lithium batteries with the 300 charge cycles limit. But it is a necessary deed with older devices in order to calibrate the battery logic and draining it all the way once a month will not negatively impact it.
Calibrating your battery does not improve the physical properties of it like adding more milliamperes. It also does not keep its health. Infact it does the opposite. Any battery that is drained to its limit can actually lose its ability to hold a charge faster than if it was charged before being drained until the device shuts down.
What will keep it in good health is using it and letting the electrons flow through once in a while if you don't unplug it often which was your original point. I just thought that I needed to explain the calibration procedure and how it doesn't improve battery health the way most people think it does.
But none of this matters because Apple themselves say that you do not have to do any procedures to the batteries in modern macbooks.
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Oh I did because the 1st link was incorrect.
Your original statement was
"Any rechargeable battery needs to be once in a while drained completely and charged again to maintain its health."
That is true because it ensures that you basically use the battery if you usually you leave it plugged it.
However your quote with all the highlights needed correction.
And for the record your 2nd link says
"An ideal use would be a commuter who uses her notebook on the train, then plugs it in at the office to charge. This keeps the battery juices flowing. If on the other hand, you use a desktop computer at work, and save a notebook for infrequent travel, Apple recommends charging and discharging its battery at least once per month. "
The first part of the text does not give you any directions on what to do if you just use your macbook normally as a mobile device. This applies to most people so they dont even tell you to drain it or any other special instructions on what to do if you just use it the way it was built for. This make your earlier quotation invalid.
The text in bold clearly states what everyone has been saying in this thread. And only relates to people who leave their macbooks plugged in most of the time which does require you to exercise the battery once in a while.
To end this: your earlier statement is true when it applies to devices who use older batteries or to devices that are plugged in most of the time. The article you quoted to respond to GGJstudios is the wrong article to prove your point. But in the end what you said is true and I only wanted to clear up the misconception about battery calibration.
I know thats apparently true, but all my friends who leave theirs plugged in manage to kill their batteries where as mine always last this long...
Anyone who keeps theirs plugged in all the time use coconut battery?
The built-in batteries in the newer Mac unibody notebooks come pre-calibrated and do not require regular calibration like the removable batteries in older Apple notebooks.
That means putting at least one cycle on the battery. It does not mean you have to completely drain and recharge the battery in one session. You get the same effect by draining to 50% and recharging twice or draining/recharging 25% and repeating 4 times. Read the WHAT IS A CYCLE? section of the Battery FAQ to understand how cycles work.
You can't lump all rechargeable batteries together and assume they are all to be treated the same way. The charging technology employed in Mac notebooks is different from that used in iPhones. That's why they have different instructions, different batteries and different logic boards.
The problem isn't leaving it plugged in after it's fully charged, which does not harm the battery. The problem arises when you leave it plugged in ALL the time, without exercising the battery.
But unplugging your MBA once every month or so, for a few hours, is plenty, according to Apple's recommendations. So leaving it plugged in 99% of the time is probably best.
That's not true. Leaving it plugged in the vast majority of the time is not good. Many people read the once-per-month recommendation out of context. As Apple states:
That does not suggest leaving it plugged in most of the time. The once per month recommendation refers to a notebook that is not being used regularly throughout the month:
There is nothing there that suggests that leaving a notebook plugged in 99% of the time is recommended.