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Optimizing Lithium-ion batteries in Apple Portable Notebooks


The purpose of this Apple-hardware based article is to provide helpful information about an important component required of all Apple portable notebooks (Apple does not call them "Laptops" because they are too hot to sit on your lap), but is not often covered in great detail in regards to its calibration and general maintenance processes.

It is the notebook battery, or more specifically, the Lithium-ion and Lithium-ion polymer batteries which Apple employs in all its portables, from the iBooks, Powerbooks of the legacy portable notebook series, to the newer Intel-duo core processor based Macbook, Macbook Air and Macbook Pro series.

The Lithium-ion polymer is the battery of choice in the later generation of Apple portables.

Some information about Apple's use of the Lithium-ion battery.

The Lithium-ion battery technology was implemented by Apple in its portable hardware line because of its excellent performance, reliability, longevity, quick recharge capability, and decent storage life at full charge. What is also beneficial about this type of battery is it good for having slow loss of charge.

Slow loss of charge with the lithium-ion battery, is paramount, for enabling any Apple notebook, to operate at its full capacity, handling the power draw, of various software and hardware functions running concurrently within the notebook and its Mac OS X volume, when running on the battery power.

This can be attributed to the increases in the amount of power, which can be transferred at a lower rate of current. This aspect of the battery alone is a big benefit for Apple portable notebook users.

Because the Lithium-ion battery is an ion polymer battery, it uses a fast charge feature to charge an Apple portable to approximately 80% of the battery capacity and then switches to trickle charging.  What this equates to, is charging the battery to power a Macbook Pro to 80% for instance, via the fast charge and then another few hours or so to trickle charge the battery to full 100% capacity.

The Importance of the Charge Cycle of the Lithium-ion polymer battery

The Charge cycle for a lithium-ion battery is the lifeline of the battery.
 Each time a battery is fully charged to 100%, this equates to 1 full charge cycle. Consequently, each time a charge cycle is completed it diminishes the overall battery capacity, but just slightly.  
 In order to gain optimum use of a lithium-ion polymer battery within a portable notebook, Apple recommends that Mac users, do not keep their portables plugged in all the time.

 When the battery has reached its 100% capacity, Apple suggests keeping the portable unplugged and encourages Mac users to work off battery power for as long as possible, for the primary purpose of making effective use of the charge cycle and to maintain the lithium-ion battery in as optimum an operating performance state, as possible.

To attain maximum use of a lithium battery during its life cycle, it is advisable as well to allow the battery to run down to drain at least once or twice a month. This step, believe it or not, is crucial and very good practice to maintain a consistent full charge cycle of the battery over its life span.  (A simple step in preventive maintenance, is the point here)

To put all these these facts to an actual scenario:
Let's say, a Macbook 13" 2.26 Ghz, is being used by its owner for a couple of hours one day and few hours at a time for 2 more days. On the fourth day, the battery has run down to 10% of its charge remaining before total drain.

For all the duration of times the Macbook was used, it is only when the battery is at 50% capacity or less, and then charged back to 100%, that one full charge cycle is calculated,
with no loss of any additional charge cycle.
The aforementioned example, demonstrates just how a lithium-ion polymer battery can be made to last, when properly used.

Calibrating Lithium-ion Polymer Batteries for Macbooks, Macbook Air and Macbook Pro portables.

The process of Calibrating an Apple portable with its lithium-ion polymer battery is easy to do
and very effective at prolonging the life of the battery.

Here are the steps to perform a proper battery calibration** as taken from Apple's Support knowledge base:

• Plug in the MagSafe Power Adapter and fully charge the battery.

• When the battery is fully charged, the light on the MagSafe Power Adapter connector
  changes to green and the Battery icon in the menu bar indicates that the battery is charged.

• Allow the battery to rest in the fully charged state for two hours or longer.

• You can use your computer during this time as long as the power adapter is plugged in.

• With the computer still on, disconnect the power adapter and continue to use your computer.

• When you see the low battery warning, save your work and close all applications.
• Keep your computer turned on until it goes to sleep.

• After the computer goes to sleep, turn it off or allow it to sleep for five hours or longer.

• Connect the power adapter and leave it connected until the battery is fully charged.

 The Apple portable can be used during this time.
I hope this resource article has assisted you, with understanding the general
features of Apple's lithium-ion battery and how it functions within Apple notebooks
and how to effectively optimize and calibrate these batteries for greater lifespan
and performance.

Thank you for reviewing this article.



Helpful links regarding Lithium-ion polymer batteries for Macbook, Macbook Air and Macbook Pro models:

**Support link for Calibration instructions listed above:
Calibrating Portable Computer battery
 Intel-based Apple Notebooks: Lithium-ion and lithium-ion polymer batteries
Managing Portable computer's battery
For Legacy Portables (iBook and Powerbook G4 models)
Apple Portables Calibrating your computer's battery for best performance

Bonus content:
Review details on the new 7 to 8 hour lithium-ion polymer battery Apple has released with its new line of Mac notebooks
Amazing New Longer Life Li-Ion batteries for Apple Notebooks

Comments (1)

Owen RubinConsultant

"To attain maximum use of a lithium battery during its life cycle, it is advisable as well to allow the battery to run down to drain at least once or twice a month. This step, believe it or not, is crucial and very good practice to maintain a consistent full charge cycle of the battery over its life span.  (A simple step in preventive maintenance, is the point here)"

I find this surprising. Apple Store employees  say this same thing, fully charge your battery, run it down as low as possible, and then fully charge it up again.  I believe this is wrong. This was a good strategy for older NiCad batteries, but everything I have read on lithium batteries say to NOT do what Apple recommends.

For example, recommends NOT fully charging the battery to extend life, as that strains the battery and shortens the life. So while leaving it plugged in may be a bad thing (Apple should be able to adjust their charging current to prevent over charging), swinging it up and down seems to be very bad.

Also from Battery University, they say "A partial discharge reduces stress and prolongs battery life. Elevated temperature and high currents also affect cycle life." Again, this is opposite of what Apple says about fully discharging before charging.  In fact, several sites I went to said DO NOT fully discharge the battery, but to top it up some, and run it down some, but do not do a full swing.

Again, see about running them down to the bottom.

The only reason to discharge and charge fully on a Mac product is to recalibrate the display of battery time. Perhaps this is why they recommend it.  

But I think this advice is shortening the life of a battery, which sells more batteries for Apple, which makes Apple more money.  Could this be their goal?

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