system
Given the following post, respond as if you're commenting on Reddit:
human
If two colleagues working on laptops share a single charger cable, switching it over as each battery approaches being depleted, are they saving energy?

As opposed to keeping chargers in their laptops continually.
gpt
The simple answer is no.  If we assume power settings are the same, load is uniform, and ignore conversion losses-- the power used would be exactly the same.  There will be some small variation in real life, though, for a few reasons.

1. Power settings on the laptops.  Laptops are often set up to run at lower power while on battery.  This isn't an intrinsic thing, though-- you could change the "plugged-in" settings to match the "on battery" settings.

2. The inefficiency of charging.  To charge a laptop battery, power is converted to DC, converted to a different voltage, and then used to charge the battery-- and all three of those steps introduce losses.  All other things equal, it would be more efficient to power the laptop directly rather than charge the battery, since it eliminates at least one of those lossy steps.

3. Power supply efficiency.  Power supplies vary widely-- they have a load at which they are most efficient.  If the particular unit with these laptops is more efficient at maximum load (charging the battery while the laptop is being used) compared to lighter load (like just using the laptop without charging the battery) then this will affect it as well.