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MacBookAir USB powered charger Answered

Hello all,

I want to share my idea and also my solution for you (when It will work out:). I wanted to build a low-cost charger for my MacBookAir Early 2014. My idea was to use my Anker Power Pack with 20100 mha to charge my battery (much higher than the battery in the MacBook Air) on the MacBookAir. Problem the outlet of the power pack is 5V/2.4A max...So I have to use a step up converter I bought one on Amazon: https://www.amazon.de/tinxi%C2%AE-Wandler-Step-up...

To get to the 14.85V stated on the outlet of the power supply. The max Amps on the power pack is only 2.4A the power supply is stating 3A.

So I put everything together and connect it to the MacBook Air. It seems to work. The charging symbol pops up in the battery screen. But it is actually not loading. The unloading process is much slower but it is not loading! In addition to that, the MacBook sometimes recognize the loader and sometimes not?

Do you have any advice on what I am doing wrong? Are the 2,4A from the battery pack to low?

After checking I guess the 0.9 mAh per USB are the problem right?


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2 years ago

Thanks. Yes, you are right...the Watts are to low. The computer needs around 45 Watts. Can`t get that from the power bank.

That is a fantastic idea to run a computer just with air....;) I guess you will be a billionaer soon if you can figure out how.

Thanks for your nput

Jack A Lopez
Jack A Lopez

2 years ago

I think you are overloading your, what you call, "Anker Power Pack". The maximum power it can supply is (5.0 V)*(2.4 A) = 12 W, according to its max current rating, which is 2.4 A.

However, the, what you call, "MacBook Air", probably wants more power than 12 watts, probably significantly more, like I dunno, maybe 50 watts? 100?

We could better guess at how much power the MacBook wants if we knew how much current it wants. That is to say, we would multiply 14.85 volts, times that unknown current (in amperes, A), to get a number for power (in watts, W)

By the way, don't you think it is strange that this MacBook runs on electricity? I mean, since it has the suffix "Air", in its name, I was expecting it to run on compressed air.

Was it naive of me to think that? Why do they even have the word, "air", in the name of that thing anyway, if it runs on electricity instead of air?