MacBook Battery Drain with the Lid Closed: How to Measure It

Choose a fixed interval, such as six or eight hours, and write down the start time, start percentage, end time, and end percentage. Battery percentage is rounded, so small changes can be coarse; compare more than one night before deciding a pattern exists. Begin each run at roughly the same charge level. Compare battery-only runs with other battery-only runs, rather than comparing one test on the adapter with another unplugged. Room temperature, battery age, workload just before sleep, and the length of the interval can all affect the result.

Prepare the MacBook in a normal, ventilated location. Save your work, close unnecessary heavy tasks, and list the attached USB, Thunderbolt, Bluetooth, and storage devices. For a baseline, disconnect accessories that are not needed. Do not put a warm or working laptop in a bag, under bedding, or inside another heat-trapping enclosure. Do not keep opening the lid to check during the test: waking the computer changes the conditions you are trying to measure.

Use the Apple menu’s Sleep command or close the lid as you normally do. Record which action you chose, then leave the device alone for the full interval. At the end, open it once and note the charge. Repeat the same steps on another comparable interval. A one-off result after a system update, backup, or unusual workload is useful context but is not enough to establish a persistent drain problem.

Capture settings and power history

Before changing a setting, save a snapshot in Terminal:

pmset -g custom
pmset -g assertions
pmset -g log | tail -250

The first command reports configured power settings, the second lists assertions active at the moment you run it, and the third shows recent power-management history. An assertion check taken in the morning is only a snapshot; it cannot reconstruct every request that existed overnight. If a particular app seems relevant, inspect assertions while that app or task is running, then compare after it exits. Apple describes PreventUserIdleSystemSleep as preventing sleep caused by user inactivity, while noting that sleep can still happen for other reasons, including lid closure. That distinction matters when interpreting a process that asks to stay awake.

Look through the power history for the sleep transition and any wake intervals before the computer became fully active again. A short background wake can be part of normal power management. A log line that mentions maintenance, network activity, a timer, or a peripheral is a clue about the recorded event, not a complete explanation of battery use. Repeated or long wake periods are more relevant than one isolated line, but they still need to be interpreted alongside the measured charge change.

For a careful walkthrough of pmset and unified logs, use the sleep and wake log guide. For state terminology, read DarkWake vs. FullWake. DarkWake does not prove that a specific third-party app or lid-angle utility caused the wake, and logs alone cannot diagnose battery health.

Test settings and accessories one at a time

Review Battery settings for options that actually appear on your Mac and macOS version. Apple notes that the available sleep and wake controls vary by model. Network wake and Power Nap are examples of features that may be present on some systems, not universal switches. If one setting fits the observed event, record its original value, change only that control, and repeat the same measurement. Restore it if the result does not support your hypothesis.

A dock, external storage device, USB receiver, Bluetooth accessory, or network condition may correlate with the loss. Change one variable at a time: disconnect one accessory, keep the same sleep duration and power source, and compare. If the result changes, reconnect that same device and repeat before treating the association as meaningful. A dock that remains connected can also make it difficult to separate system sleep from an external display or accessory behavior.

If the Mac seems to wake immediately after closing, the main problem may be a sleep transition that never settles. Follow the immediate-wake troubleshooting steps. Avoid changing multiple pmset values, disabling every wake feature, or using a persistent keep-awake command as a first response. Broad changes can hide the cause and may increase energy use.

When to ask for service

If the measured drain is severe and repeats with accessories disconnected, settings recorded, and the Mac otherwise idle, check battery health in System Settings and consult Apple’s current battery guidance. If the computer becomes unusually warm while closed, stop the test and let it cool in a ventilated place. A power log cannot determine whether a cell, lid sensor, or logic board needs service. Provide Apple Support with the Mac model, macOS version, repeatable test duration, starting and ending charge, power conditions, and a small redacted log excerpt.

FAQ

What percentage loss overnight is normal? There is no single percentage that applies to every model, battery age, macOS release, setting, and test setup. Establish a repeatable baseline for your own Mac.

Does any DarkWake mean excessive drain? No. The term describes a power state, not a charge measurement. Compare the duration and repetition of wake intervals with the actual battery change.

Should I turn off network wake or Power Nap? Only if the control is present and relevant to your case. Change one setting and repeat the controlled test; some models do not offer these options.

Can I run a download overnight with the lid closed? Do not assume that a closed laptop will keep running, and do not run a warm workload inside an enclosed space. Use a ventilated, supported setup and a task that can pause or resume safely.

The Mac Lid Sleep utility can help organize lid-related observations, but it is not an Apple-certified battery or hardware repair service. Check compatibility and the FAQ for supported models and product limits.