Why did my MacBook came from 100% to 4% unused on a plane?

[bearinthetown]

I had my MacBook Air 2018 in a backpack on two flights, I haven't been using it for about 36h. I charged it to 100% before my flight. Today I opened it and it was 4%. How did it happen? Do planes somehow make batteries drain? I haven't heard anything about it. I hope my MacBook is alright.

 

[chrfr]

I had my MacBook Air 2018 in a backpack on two flights, I haven't been using it for about 36h. I charged it to 100% before my flight. Today I opened it and it was 4%. How did it happen? Do planes somehow make batteries drain? I haven't heard anything about it. I hope my MacBook is alright.

I'm sure your computer is fine. Something probably caused it to wake up in your bag.

 

[AxelFoley]

I had my MacBook Air 2018 in a backpack on two flights, I haven't been using it for about 36h. I charged it to 100% before my flight. Today I opened it and it was 4%. How did it happen? Do planes somehow make batteries drain? I haven't heard anything about it. I hope my MacBook is alright.

That has happened to me as well during an International Flight. I had the computer in sleep mode and by the time I got to LON from LAX it was under 5%. Since then I completely shut off the MacBook Air before I board and things have been fine. I think CHRFR is correct. Something awakened your MacBook while in your bag and continued to search for a connection throughout your journey and drained the battery. Your MacBook should be fine as you may have already noticed since then.
Safe Travels.

Axel F.

 

[bearinthetown]

Great idea to turn off MacBook on flights, I'm gonna start doing that, bros.

 

[Saturn007]

Couple of thoughts about that... If Power Nap under Battery (in Energy Saver preferences) is checked On, the laptop will, from time to time, try to connect to WiFi. Apps that use WiFi or Notifications could also be on and eat up battery life.

Shutting the laptop down entirely is a smart approach -- unless, of course, you want to use it on your flights!