Hello Ifixit community, this is my first post. The problem is as follows:

My macbook air 13" Mid 2012 keeps on turning off abruptly when unplugged. It can last from anywhere around 2 minutes, to nothing (a small sound appears when powering on, yet cuts off even before booting sound). Initially it would last longer, yet quickly degraded to its current status.

However, when plugged in, it works with no problem at all...

I initially thought the battery must have degraded really, really quickly (i replaced it about 2-3 months ago), yet as can be seen with coconut, its in good health with realtively few cycles.

I hace done an smc reset with no results.

I have also done pram, no results.

I have run diagnostics, no faults appear.

I have attempted completely discharging battery, but as it turns off when unplugged, this is something I can not do.

What I am guessing (in light that the battery actually comes up as "good") is that the laptop somehow thinks that it is drawing too much power and thus automatically closing itself. When plugged, there is infinite power so it doesnt feel the need to close itself, even if it might see itself drawing too much power.

I think this might be the issue because the problem slowly started after very heavy usage of playing CIV 6 for a week where it was surely gobbling up power. Now the component that measures this "power-gobbling" (:)) rate is either broken or uncalibrated as a result of this heavy use.

But of course this is purely a guestimate...

It would be much appreciated if someone helped me out!!