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I purchased this Mac Air one year ago and just use it for school. I charged it probably for less than 365 times already and right now the screen shows that I have 5 hours and 45 mins when it's at 100%. I remember that it used to be 7 hours.. Is this normal? I always turn up the brightness 50% and only use it for school work (essay writing, researching, etc.)
Thanks!
MacBook, iOS 7.0.4
It's not abnormal. Some things get better with age but battery life is not among them. Furthermore, the displayed battery charge remaining in hours and minutes is little more than an educated guess predicated upon present current draw and previous full charge capacity.
Upgrading to Mavericks may increase its battery life due to efficiency improvements. Mine got about a 20% increase after upgrading from Mountain Lion.
At least once a month you should run it on battery power to exercise the battery. Cycle it to about 40% left then recharge. Do not cycle it to a near zero charge.
From: http://www.apple.com/batteries/
Exercise Your Machine
Lithium-ion polymer batteries need to be used for maximum performance. If you don’t use your device often, be sure to complete a charge cycle at least once a month.
Tips to help you extend your battery life.
Considerations for the long life of your Macbook Air. Handling and environmental care tips
General consideration of your MacBook battery
Contrary to popular myths about notebook batteries, there is protection circuitry in your Macbook and therefore you cannot ‘overcharge’ your notebook when plugged in and already fully charged.
However if you do not plan on using your notebook for several hours, turn it off (plugged in or otherwise), since you do not want your Macbook ‘both always plugged in and in sleep mode’.
A lot of battery experts call the use of Lithium-Ion cells the "80% Rule", meaning use 80% of the full charge or so, then recharge them for longer overall life. The only quantified damage done in the use of Lithium Ion batteries are instances where the internal notebook battery is “often drained very low”, this is bad general use of your notebook battery.
A person who has, for example, 300 charge cycles on their battery and is recharging at say 40% remaining of a 100% charge has a better battery condition state than, say, another person who has 300 charge cycles on their battery and is recharging at say 10-15% remaining on a 100% charge. DoD (depth of discharge) is much more important on the wear and tear on your Macbook’s battery than the count of charge cycles. There is no set “mile” or wear from a charge cycle in specific. Frequent high depth of discharge rates (draining the battery very low) on a Lithium battery will hasten the lowering of maximum battery capacity.
All batteries in any device are a consumable meant to be replaced eventually after much time, even under perfect use conditions.
➕If the massive amount of data that exists on lithium batteries were to be condensed into a simplex, helpful, and memorable bit of information it would be:
1. While realistically a bit impractical during normal everyday use, a lithium battery's longevity and its chemistry's health is most happy swinging back and forth between 20% and 85% charge roughly.
2. Do not purposefully drain your battery very low (10% and less), and do not keep them charged often or always high (100%).
3. Lithium batteries do not like the following:
A: Deep discharges, as meaning roughly 10% or less on a frequent basis.
B: Rapid discharges as referring to energy intensive gaming on battery on a frequent basis (in which case while gaming, if possible, do same on power rather than battery). This is a minor consideration.
C: Constant inflation, as meaning always or most often on charge, and certainly not both in sleep mode and on charge always or often.
From Apple on batteries:
http://www.apple.com/batteries/notebooks.html
http://support.apple.com/kb/HT1446
"Apple does not recommend leaving your portable plugged in all the time."
How long is the battery life in a Mac Air 13inch?
