How long does the battery last on mid-2011 MacBook Airs?

Solution 1:

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.

Solution 2:

I don't know what the expected life is (although the specs on the Apple website are always pretty accurate for me) - but of course it depends on your usage.

As far as I understand it, the MBA batteries are of a similar design to the MBP ones of the same generation. I always link to this page (which is on the Apple Discussions site) about preserving battery life - as I've followed it as closely to the letter as I can, and I still get a good 85-90% of the life out of my two-year old pro. I've quoted some below.

Do’s & Don’ts

DO use your battery frequently and lightly, ideally completing 1-2 charge cycles per week (minimum one charge cycle per month).

DO properly calibrate your battery when new and approximately every 2-3 months thereafter.

DON’T fully discharge your battery frequently (the infrequent, periodic calibration is an exception).

DON’T store your battery (or your computer) in a high temperature environment, such as the trunk of a car, especially a fully-charged battery.

DON’T run your MacBook or MacBook Pro on AC power with the battery removed.

Note: I had a quick look and the pro and air batteries are the same material, so the above instructions will work well for them too.