Another 2012 Air user here.
The battery doesn't hold a charge anymore, but as long as it's plugged in, it keeps chugging along.
I replaced my original in a 2012 pro. The replacement died so I run it without a battery.
Wow turns out there's a whole community of us! Same boat. I usually recycle, hand me down, trade-in but have really had a hard time letting that little one go.
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