External drives · Speed, cables and hardware
Does keeping an external SSD plugged in drain my MacBook's battery?
Short answer: A little — a bus-powered drive draws power from the Mac, more while copying and less when idle; SSDs use less than hard disks. Eject it on battery if you don't need it. Storage Studio paces its background work on battery.
A little. A bus-powered drive draws its power from the Mac, so it uses some battery while connected — more when it's busy copying, much less when idle. SSDs generally use less power than spinning hard disks.
If you're on battery and don't need anything on the drive, ejecting it saves a little power. Storage Studio itself paces its background work and holds back on battery, so it won't keep the drive busy while you're working unplugged.