86 MACWORLD SEPTEMBER 2020
WORKINGMAC WHY YOU SHOULDN’T KEEP A LAPTOP CHARGED AT 100%
Routinely unplug your laptop, as
frequently as daily, and let it drop its power
down to the 30 to 40 percent range.
Don’t fully discharge your battery
regularly—that is, don’t let it run down to
zero. As Battery University (not a degree-
granting institution) notes (go.macworld.
com/btun), “If at all possible, avoid full
discharges and charge the battery more
often between uses....There is no memory
and the battery does not need periodic full
discharge cycles to prolong life.”
With modern Apple laptops, in
macOS Catalina’s 10.5.5 release you can
make sure that Battery Health
Management is enabled in the Energy
Saver preference pane’s Battery tab by
clicking Battery Health.
> In macOS 11 Big Sir, recent Mac
laptops will have more modern options
enabled by default.
If you’d like more details, read on.THE LOWDOWN ON TOPPING
UP BATTERIES
Lithium-ion batteries are a far sight better
than their nickel-based predecessors.
Even the later nickel-metal hydride (NiMH)
batteries required a regular full
discharge—taking the battery down to no
stored capacity—to keep them in good
shape. Li-ion batteries are excellent at
charging and discharging in varying
amounts over time and losing relatively
little charge when idle for long periods.
But the way in which they store energy
requires careful
charging past about
80 percent capacity.
After that point, it’s
easy for the
batteries to
overheat, which can
damage them or, in
the worst case,
cause bulging or
even fires. That’s
why battery circuitry
on all devices
throttles charging
speed from 80 to
100 percent.In macOS Catalina’s 10.5.5 release make sure that Battery Health
Management is enabled in the Energy Saver preference pane.