it turn itself off

Hello lenard15,

If the battery on your MacBook Air can not hold a charge, updating the operating system will not resolve the issue. The resources below will explain how to troubleshoot the issue with the battery. I've highlighted some key information for you here. Click on the links for complete details.

About Mac notebook batteries
https://support.apple.com/en-us/HT204054

• Consumed / depleted: Consumable parts are those that deplete over time as their internal components are used. Batteries, due to their chemical components, are considered consumables, and slowly over time they lose their ability to hold a charge. If the cycle count on a battery exceeds its expected limit, the battery is considered consumed.
• Defective: Batteries are considered defective when they stop working due to a defect in materials or workmanship, or due to a manufacturing defect. Defective batteries are covered under Apple's one-year limited warranty and extended-service contracts.

The battery status menu

Your primary resource for viewing battery status is the battery status menu. The battery status menu shows you how much charge your battery has and whether it's currently charging. This menu is at the right side of the menu bar:

The battery status menu updates frequently and changes depending on your screen brightness and system workload. You may see the time remaining drop significantly, for instance, if it updates while opening a very large file or starting up an application. It's important to remember it's an estimate based on what your computer is doing at the specific time it updates.

To see the health of your battery, hold the Option key and click the battery icon:

You'll see one of the following status indicators:

• Normal: The battery is functioning normally.
  
• Replace Soon: The battery is functioning normally but holds less charge than it did when it was new. You should monitor the health of the battery by checking the battery status menu periodically.
  
• Replace Now: The battery is functioning normally but holds significantly less charge than it did when it was new. You can safely continue using your computer, but if its lowered charging capacity is affecting your experience, you should take it to an Apple Store or Apple-authorized service provider.
  
• Service Battery: The battery isn’t functioning normally. You can safely use your Mac when it's connected to an appropriate power adapter, but you should take it to an Apple Store or Apple-authorized service provider as soon as possible.

Note: While some third-party apps report on battery health conditions, the data reported by these apps may be inaccurate and isn't a conclusive indication of actual diminished system run time. It's recommended that you rely on the information reported in the battery health menu (shown and described above).

Troubleshooting batteries

A great place to start when troubleshooting battery issues is the built-in diagnostics that are available on your Mac notebook. Review the following articles for more information on using diagnostics.

• Using Apple Diagnostics
• Using Apple Hardware Test

Note: The additional troubleshooting recommended below assumes you have run the above diagnostic appropriate for your computer and that no issues were found.

My battery isn't charging

Confirm the correct wattage AC adapter for the computer. A power adapter rated for a lower wattage than is required for the system may not reliably charge the computer. For assistance identifying the proper adapter, review Find the right power adapter and cord for your Mac notebook. Additional adapter troubleshooting is available in Troubleshooting MagSafe adapters. If issues persist, reset the SMC.

Servicing the battery in your Mac notebook

MacBook, MacBook Air, and MacBook Pro computers with built-in batteries should only have their batteries replaced by an Apple Authorized Service Provider or Apple Retail Store. Attempting to replace a built-in battery yourself could damage your equipment, and such damage is not covered by warranty.

These Mac notebooks have built-in batteries:

• MacBook (13-inch, Late 2009) and later
• All MacBook Air computers
• All MacBook Pro computers with Retina display
• MacBook Pro (13-inch, Mid 2009) and later; MacBook Pro (15-inch, Mid 2009) and later

Most older Mac notebooks have removable batteries you can replace yourself. Contact an Apple Authorized Service Provider or Apple Retail Store for assistance servicing a removable battery.

Last Modified: Dec 9, 2015

Take care,