Q: My MacBook Air has a prolem with Battery

Your MacBook is under Apple Care warranty now so you'd better send your MacBook to Apple Authorised repair centre to replace the battery as soon as possible.

Usually the battery itself is covered for a year, however the usual AppleCare extended

plan runs for three years including the first year of complimentary service coverage if

bought within the time-frame, as the extended plan adds to total includes and original.

Were you able to contact an Apple authorized service and/or sales provider in Vietnam?

You may be able to find Authorized service repair by use of Locate Apple pages:

• Apple - Find Location - by city/Vietnam (sales + service locator) results of two linked below

https://locate.apple.com/vn/en/

• Mac service locations (4 found) near Ho Chi Minh City, Ho Chi Minh City, Vietnam

https://locate.apple.com/vn/en/service/?pt=4&lat=10.75&lon=106.6666667

• Mac service locations (3 found) near Hanoi, Thành Phố Hà Nội, Vietnam

https://locate.apple.com/vn/en/service/?pt=4&lat=21.030493&lon=105.835934

http://www.apple.com/vn/support/contact/

http://www.apple.com/asia/support/macbookair/

About batteries and power:

http://www.apple.com/asia/support/macbookair/batteries_power/

The computer should have a diagnostic performed to see if all that is acting up, is the

battery; since they do age and depending on use situations and conditions, like air

temperature and how the computer is used, if it were ever let run completely flat, so

the battery would sustain damages if let run until empty of power; these can all make

for a shorter than ideal battery life. Even using the screen on bright, can deplete the

ability for the battery to fully recharge over a possibly longer life span, over years...

Battery cycles and voltage capacities, storage abilities, are impacted by actual use.

You could ask the authorized Apple service provider if they could replace the battery

under the extended AppleCare plan before the time runs out. They may, however I

am not a party to any determination they may make, as a participant in a peer user

to user help discussions section, and not representative of Apple, Inc. or its policies.

According to the serial number you posted (usually is not allowed & gets deleted by

the Hosts) I used this lookup https://www.powerbookmedic.com/identify-mac-serial.php

the resulting information came up from the site:

or see Apple Support article to confirm build model details

How to identify your MacBook Air - Apple Support

If you are asked to purchase the replacement battery instead, as may be the case if

the company performing the service does not see the part as one covered under the

AppleCare plan, the part may in cost (citing in USD $) as much as $160. or so. They

may or may not be able to replace the battery for free under AppleCare. I can't say.

They may (or not) perform the labor for free, if you have to buy their battery, if the unit

(replacement battery) is not covered by AppleCare.

Or you could see about buying a quality replacement battery and install it yourself...

•MacBook Air 13-inch Mid 2012 Repair guide - iFixit:

https://www.ifixit.com/Device/MacBook_Air_13%22_Mid_2012

You may be able to privately purchase a quality replacement battery from reputable

source and then use a free online repair guide to remove the old one & install new

one, so long as part is correct for the model MacBook/Air 5.2  you have. According

to the powerbookmedic.com lookup, the battery number for your MacBook/Air, is:

661-6639 Battery, w/Cover -- this part would be the original number though others may

be utilized if Apple part replacements had seen an upgrade or other inventory change.

{Most all those who reply here are volunteer and try to help as best as we can, but

do not get any compensation; your best and possibly only action there is to contact

the local affiliate and authorized Apple service and/or sales companies who repair or

replace the Apple product in your country. The details in an AppleCare agreement may

vary depending on the location or country where it is being used, & by product covered.}

http://www.apple.com/support/applecare/

Sorry to not be able to answer about how Apple Care may be interpreted in your locality;

however you should contact the Apple authorized local entity for service and ask them

because the battery may be seen as a consumable, and perhaps not expected to last

more than one year. This would not be unexpected, if they were to suggest a short limit.

You may be able to see about setting an appointment or contact one of the Vietnam

Apple authorized service affiliated businesses, if not in the city (search I used) indicates

choose a different city name in the Locator, under Service. You may also check to see

if the Sales locator search brings up additional ones. The Map has click on to get info.

Two cities' service result links, from Country search appear above. That may help...

You should be able to contact the company nearest you if they do not appear in the

Apple Locator by city name and ask the question of their service people, if they do

repair replacement under AppleCare.

In any event, sorry about the inconvenience.

Good luck & happy computing!

Addendum:

Some of the Sales Locations (premium) may have a service center, so those authorized agents

whose business model allows them to perform authorized AppleCare repair and replacements

should not be a problem; as I suggested in earlier post, you may ask them if they provide this

service, and if their physical location is nearer to you, that would be helpful with less travels.

There were more companies appearing in the Apple Locator for Sales, compared to Service.

A link to Apple Find Locations (Sales) for Ho Chi Minh City, Vietnam, as follows:

• Mac sales locations (15 total found) near Ho Chi Minh City, Ho Chi Minh City, Vietnam

https://locate.apple.com/vn/en/sales/?pt=4&lat=10.75&lon=106.6666667

So some of these "premium" may offer services in addition to sales, such as Specialist + repair service.

(The host edited your original post/title and moved it into a new thread of its own, by the way.)

Good luck in this matter!