I know that one of the big innovations in the MacBook Air was in the battery (which gets most of the internal volume of the computer!)
What is a normal loss of battery life (change in usable time on battery starting from a full charge) for a mid-2011 13" MacBook Air? After how many charge cycles does one expect to see a substantial reduction in usable time? Is there any recommended course of action for someone to take to slow or reverse this degradation once it begins?
Best Answer
Battery Life
Apple's documentation states that the battery of the Macbook Air performs just like the batteries of the Macbook Pro:
The built-in battery of your MacBook, MacBook Pro or MacBook Air is designed to deliver up to 1000 full charge and discharge cycles before it reaches 80 percent of its original capacity.
In addition, Adaptive Charging reduces the wear and tear on the battery giving it a lifespan of up to 5 years.
During this lifespan the batteries will have a fast charge to 80% of the current battery capacity (2-3 hours). [source]
Battery Maintenance
Do not leave your Macbook plugged in all the time. The battery juices need to move from time to time. It's recommended that you charge and discharge the battery at least once per month.
Temperature: Keeping your Mac at room temperature (22°C/72°F) is ideal.
Long Term Storage: Apple recommends that you store the battery with a 50% charge, if you are not planning on using it for at least half a year.
The innovation in the design of the battery of the Macbook Air was not about increasing capacity, but about the ability to manufactures them very thin. The batteries of the Macbook Air are located towards the thin end of the Macbook Air.