Delete comment from: Ken Shirriff's blog
Item 5: "If the Mac is happy with the charger ID, it switches the power input to the internal power conversion circuit and starts using the input power."
It’s not quite right, it’s right: If Mac does not like the charger ID, it disconnects the battery charge circuits inside, but if the voltage at the input suits it, it works from an external adapter. "
This can be easily checked if you disconnect (stick tape) the third pin - there is no charge, but the Mac works from an AC adapter.
Nov 14, 2019, 11:19:52 PM
Posted to Teardown and exploration of Apple's Magsafe connector