MacBook turns off when charger is disconnected.

Lets check the battery and the charger. Install this gem of an app CoconutBattery take a snapshot of the main window with the charger plugged in and see if you can get one with the charger is disconnected before it shutdown. Paste both here for us to see Adicionar imagens a uma pergunta já existente

Have you tried running the onboard diagnostics? Restart the system and press the 'D key did you get an error message? Let us know as well.

I read somewhere that it might be fixed by discharging it to zero and then charging it again. I dd not know how to discharge it since I could not use it without the charger being plugged. I turned it on and I quickly opened youtube and I played a 4k video with keyboard and screen into full brightness. I also played multiple videos in the background with full volume. The laptop was working so fine without any problem and it did not shut down. I discharged it from 100% to 60% and as a test to see if the problem is fixed or not. I closed the video and everything. it immediately shut down. This time, I turned on and did the same thing again playing videos and so on. but this time I connected my phone and iPad so it would be discharged faster. it was working perfectly.

When it got to around 20% I closed the videos and everything but this time it was working until it hit 0% without the charger and everything being closed(no video, nothing). I thought the problem was gone but when I charged it I realized it happen when it's over 20% charge. I gave up.

After 10 hours, tonight. I turned on and I could not turn it on. it was like the computer was dead. I plugged to the charger and it was not charging. After 2 hours I pressed the power button and it unexpectedly came back to life. And it's working without any problem. I think the problem is gone this time. it was a wired experience.

@danj thank you for your reply. if the problem will come back I will do what you said.

Weird PMIC? Could be suffering from heat damage, or overcharged.