How to self-diagnose Apple MacBook air 2013?

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Egorus2015-04-22 08:27:58

macbook

Egorus, 2015-04-22 08:27:58

Hello!
Macbook Air stopped charging and turns off instantly after unplugging charger. At the same time, he writes "until fully charged 20:00", but this is not true. Switching on in diagnostic mode (with the D key) did not reveal any abnormalities, resetting the SMC did not change anything either.
"About the system" gives the following:
And everything seems to be fine ... Well, in the sense that "Status: Normal, Battery installed: Yes"
If I were 100% sure that the problem was in the battery, I would buy it and install it ... But I don’t know how to accurately determine the source of a breakdown using system tools. Tell?