Mac battery draining fast while awake

After this, the battery percentage drops at a rate that actually matches what you're doing on the Mac.

Why this happens

Apple's own description of Activity Monitor's Energy Impact column calls it "a relative measure of the current energy consumption of the app" — it's a unitless score built from CPU time and wake-ups, not exact watts, but it reliably ranks which process is actually costing you battery right now. A single process with a persistently high score, especially one that looks idle, is the direct signal to act on — compare it against the "12 hr Power" column to tell a one-time spike from something that's been draining you for hours.

The most commonly reported real culprits on Apple Silicon Macs are browser tabs playing video or running WebGL/canvas content (a single video tab can draw several times more power than a handful of idle ones), background sync and indexing daemons (mdworker/Spotlight, photoanalysisd/iCloud Photos), and occasionally a genuinely stuck process — Xcode's Simulator and SwiftUI previews have a documented history of pegging CPU high enough to visibly spike system-wide power draw. None of this is unique to Apple Silicon, but Apple Silicon Macs no longer have a discrete GPU to switch away from under light load the way older Intel MacBook Pros did, which is part of why their battery life is normally so much better when nothing is actually misbehaving — when something does misbehave, it stands out more clearly on the Energy tab rather than being masked by other overhead.

Fix it

1. Open Activity Monitor, click the Energy tab, and sort by Energy Impact. Whatever sits at the top with a persistently high number — not just a brief spike — is your culprit. Check the 12 hr Power column alongside it to confirm it's sustained rather than a one-off.

2. From Terminal, confirm the same top-CPU process another way and see the actual charge state while you're at it:

   ● Reads the system

   What it does: prints current battery charge, charging state, and time remaining.

   After: nothing changes, this only reads.

   pmset -g batt

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   Typical output: Now drawing from 'Battery Power' -InternalBattery-0 90%; discharging; 6:32 remaining. Right after unplugging or a workload change, the time-remaining field commonly shows (no estimate) for a few minutes while the estimator gets a stable read — that's normal, not a fault.

3. Once you've identified the process, quit it normally from its own app first — that's the safe, reversible path. If it's unresponsive or it's a background helper with no visible window, end it directly:

   ▲ Changes running state

   What it does: force-quits the named process by its exact command name from Activity Monitor.

   After: any unsaved work in that process is lost, same as force-quitting it from the Dock; the energy drain stops immediately.

   killall "ProcessName"

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   Revert: nothing to restore — just reopen the app normally if you need it again.

Still broken?

• The Mac won't go to sleep at all, awake or not
• kernel_task itself is the one using unusual CPU, with fans at max

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Related problems

• Mac won't go to sleep on its own
• kernel_task using high CPU on Apple Silicon