Apple silicon Macs (M1, M2, M3) are renowned for their incredible battery life, often lasting a full workday on a single charge. However, if your Mac is suddenly draining 20% of its battery in an hour, a rogue application or background process is likely the culprit. While the macOS menubar provides a quick glance at “Apps Using Significant Energy,” it lacks the granular detail needed for serious troubleshooting. To truly diagnose power consumption issues, you must use the built-in Activity Monitor.
Step 1: Open Activity Monitor
Activity Monitor is a system utility located in your Utilities folder.
- Press Command + Space to open Spotlight Search.
- Type
Activity Monitorand press Return.
By default, Activity Monitor opens to the CPU tab. While high CPU usage usually correlates with battery drain, it does not tell the whole story. Applications can drain power in other ways, such as keeping the Wi-Fi radio active or preventing the computer from sleeping.
Step 2: Navigate to the Energy Tab
At the top of the Activity Monitor window, click on the Energy tab. This section is specifically designed to analyze power consumption over time.
Step 3: Understand the Energy Metrics
The Energy tab contains several columns. The two most important are:
- Energy Impact: This represents the real-time power consumption of the app at this exact moment. It is a composite score calculated by macOS, factoring in CPU usage, network activity, disk access, and screen brightness required by the app. If you see an app spiking to “150” or higher, it is currently drawing massive power.
- 12 hr Power (or Avg Energy Impact): This is arguably the more useful metric for diagnosing chronic battery drain. It shows the average energy impact of the app over the last 12 hours (or since the Mac started on battery power). An app might have a low real-time Energy Impact when you look at it, but a high 12 hr Power score indicates it was draining the battery heavily in the background earlier in the day.
Click the column header for 12 hr Power to sort the list from highest to lowest. The worst offenders will rise to the top.
Step 4: Check for “Preventing Sleep”
Sometimes, the issue isn’t an app using too much CPU, but an app preventing your Mac from entering its low-power sleep state when you close the lid.
Look at the Preventing Sleep column.
- If an app says Yes, it means it holds an “assertion” that blocks the system from sleeping.
- This is normal for apps like Spotify (while music is playing) or Zoom (during a meeting).
- However, if a background utility or a web browser tab says “Yes” while you aren’t actively using it, you have found your battery drainer.
Step 5: Inspecting App Naps
macOS has a feature called “App Nap.” When an application is open but hidden behind other windows (and not doing any active work like playing audio), macOS puts it into a suspended state to save battery.
Look at the App Nap column.
- If an app says Yes, macOS successfully suspended it.
- If an app says No, it means the app is demanding constant background processing time. Poorly optimized Electron apps (like some chat clients) often fail to enter App Nap, resulting in continuous, silent battery drain.
Step 6: Taking Action
Once you identify the rogue application, you have several options:
- Force Quit: Select the app in the list and click the X icon at the top of the window to force it to close.
- Check for Updates: Software bugs often cause infinite loops that drain the battery. Check if the developer has released a patch.
- Uninstall: If it is a non-essential background utility that refuses to sleep, consider uninstalling it entirely.