Chosen Solution
So im having this issue with my MacBook Air early 2014. It won´t turn on unless plugged in to the charger and after booting up, i can unplug the charger and it will work fine. already reset SMCRestore OS via USBTried new battery Issue persists. Any help will be thanked!
That points to a logic board issue at charging/main power circuit. Usually that comes from a liquid damaged Mac or a poor quality aftermarket charger. One way or the other it would need component level repair or a logic board replacement.
Though I had 100% charge on my battery, my Macbook Air 2013 won’t turn on without connection to the power adapter. It would turn off when unplugged. I did as suggested - PRAM reset and SMC resets but the problem persisted. Figured I had to buy a new battery, even when running a Apple Diagnostis said my device has no problems. I decide to practice removing the old batteries and putting them back so I know what to do when the new batteries came. Interestingly, disconnecting the battery from the logic board and reconnecting solved the problem of needing a power adapter to run. My unit now works pretty well….
