use DC power while plugged in without charging the battery?

I'm aware that keeping the battery fully charged is bad for the battery health. However, I often need to use my computer and it easily consumes a lot of battery power in a short time. (connected to an external display) Is there any way one can use the DC power without charging the battery, when keeping the power plug connected? I'm using a MacBook, but this applies to all laptops. P.S. I'm only asking if there is such a mechanism to accomplish this, there's no need to comment on the battery per se or how to extend the battery life.

Question by Shefield on Super User, licensed CC BY-SA. We show a short excerpt and link to the original thread as credit.