[otheotheothe]

It does slow charge, i use my external Anker Powercore Plus battery pack with it, while its not able to charge it while running because the MBP draws more Power than the Anker Battery can output it EXTENDS its battery lifetime very noticeably.

[ardaozkal]

While that'd work, I'd advise against it as I feel like that'd needlessly heat the battery and reduce its life.

[unwind]

If that were true, wouldn't it be the job of the computer's battery management system to make sure it didn't happen?

Forcing user to learn all kinds of magic rules for how to "treat their battery" seems very old-fashioned and strange.

[dev_tty01]

No, when providing supplemental power the battery current is lower and therefore has less heating. This will extend the life of the battery.