Whether you use your laptop when traveling or even just working in different places in your home, the importance of having a long-lasting battery is most evident when you're forced to find an electrical outlet to plug in. After all, a laptop is nothing more than a portable computer, so how long its battery lasts is an important characteristic you should consider when looking for a new model. In this article, we detail the methodology of our battery tests, both when charging and discharging the laptop, what the results mean in practical use, and how you can get the most battery out of your laptop.
Having a long-lasting laptop battery is most important if you expect to be doing lots of productivity work away from an easily accessible power source or if you don't expect to have a reliable power source handy at all times. This is important if you're a student who has to commute to campus or walk long distances between classes or someone who works remotely or while on business trips. It's a big headache if you end up being interrupted by a low battery prompt or end up losing data from an emergency shutoff.
We run two different types of tests to score how well the battery performs: discharge tests (how long the battery lasts) with different types of workloads, and a charge test (how long it takes the laptop to reach a full charge). Some settings remain the same among all our tests, but others have to be changed depending on the workload type and operating system.
We perform all our battery discharge and charge tests in a small, temperature-controlled room set to 22°C (71.6°F), with a tolerance of ±0.5°C. For all the battery discharge tests, regardless of the operating system, we set the display to its native resolution and highest available refresh rate, calibrate its brightness to 200cd/m², and set it to never sleep or dim. We turn off all keyboard and RGB backlighting, mute the speakers, and close all other background apps and processes except those necessary for the laptop to function.
The power mode and other optimizations differ depending on the OS:
We keep the laptop plugged in using its included power adapter and ensure it's at 100% battery before performing our tests. We only unplug it once we begin each discharge test. Depending on the workload being tested, we use different settings for each operating system:
We use the most popular web browser for each OS:
We use the same version of VLC Media Player for each OS:
Gaming (Windows and macOS):
We run Unigine Heaven 4.0 with the following options:
Note: For laptops that don't use a 16:9 display, we run the benchmark on an external 16:9, 1080p monitor. In these situations, we ensure that the external monitor is the only active display, and turn off the laptop screen. For some MacBooks, this may not be possible, so we have to mirror the display.
Gaming (Chrome OS):
Unigine Heaven 4.0 isn't compatible with Chrome OS, so we use the Basemark GPU app from the Google Play Store with the following settings:
We note the rated capacity of the battery, which is visible on the laptop battery itself during the teardown for our Serviceability test. If this isn't possible, we note the typical capacity listed on the manufacturer's spec sheet.
While the typical capacity denotes the average (or expected) capacity for batteries in a batch, the rated capacity refers to the minimum capacity verified by industry testing standards and is more reflective of what to expect in real-world use.
We test how long a fully charged battery lasts during typical web browsing, using the most popular browser for each corresponding OS. We maximize the application, so it takes up the entire screen, which is different from fullscreening the entire browser using the F11 key.
We turn the Wi-Fi on and Bluetooth off and run an automatic script that simulates viewing and scrolling through various web pages. These include RTINGS.com, Wikipedia, and NPR, as well as an embedded 6-minute YouTube video that takes up the entire browser window. We run the test until the laptop dies or goes into emergency shutoff mode. Once we power the laptop back on, we record the elapsed time until shutoff that was recorded by the script.
This test affects the total battery score the most because we expect it to reflect most people's workloads. Alongside general web browsing, we also expect this result to closely reflect workloads that include using a single application at a time to run light productivity tasks. These include word processing and spreadsheets, as well as most idle tasks like reading articles.
We test how long a fully charged battery lasts during video playback, using VLC Media Player to play back a fullscreen test video on a continuous loop.
We turn on Airplane Mode, which disables Wi-Fi and Bluetooth. With the laptop plugged in, we warm up the screen by playing the test video on a loop for a few minutes. The video consists of pre-recorded gameplay from various game genres, including sports, racing, and FPS. We then unplug the laptop when starting the test, then run it until the laptop dies or goes into emergency shutoff mode. Once we power the laptop back on, we note the elapsed time that the laptop was awake, recorded by our lightweight script in the background.
This test generally reflects the laptop's battery life when watching videos, but keep in mind that the app or website you use for video playback may affect battery life differently and give a different result.
We test how long a fully charged battery lasts during a simulated gaming workload. On Windows and macOS, we run Unigine Heaven, while we use the Basemark GPU app from the Google Play Store on Chrome OS.
Once again, we turn on Airplane Mode to disable Wi-Fi and Bluetooth. We run the benchmarks on full screen until the laptop dies or goes into emergency shutoff mode. Once we power the laptop back on, we note the elapsed time until shutoff that was recorded by our lightweight script in the background.
This test reflects the laptop's battery life while under heavy CPU and GPU loads, similar to what you can get when playing modern AAA games. It also puts similar pressure on the system as 3D rendering and physics simulations, so it gives you a good indication of how much you can expect to get done before needing to plug in.
With the laptop completely dead, we test how long it takes to recharge it using its included power adapter. Rather than rely on any onboard battery indicators, we use a power meter to measure how much power the laptop pulls from a wall outlet while charging to determine when the battery is full.
We begin the timer when we plug the laptop in. Afterward, we note the elapsed time when the laptop pulls less than 0.5W of power; this is when we consider it fully charged. The laptop remains powered off for this test.
This test matters most for people who are constantly on the move and need to charge their laptop with limited time or don't have a reliable power source.
When using your laptop on the go, you have to balance the performance you need with the battery life you want. For example, even though it technically might be possible to watch an entire season of a TV show on a single full charge, you'd need to dim the screen to its lowest setting and turn your speakers off, which would result in a less than ideal viewing experience. That said, there are still measures you can take in nearly all situations to help increase your battery life, regardless of the workloads you need to run.
Note: Manually turning off your Bluetooth no longer significantly improves battery life as much as it did around the era of Bluetooth 2.0. Modern Bluetooth adapters are capable of intelligently managing their power consumption, so you shouldn't see any noticeable increases in battery even if you go out of your way to turn them off and on yourself. You'll still have good battery and usability as long as your Bluetooth peripherals stay nearby.
When charging your battery, the easiest way to ensure that your battery charges as quickly as possible is to use the provided power adapter. These are typically rated at the highest wattage supported by the laptop. However, there are some exceptions, like some variants of the Apple MacBook Pro 14 (2021), where you'll need to buy the higher-wattage charging brick separately to benefit from the fast charging feature.
If you need to charge your battery as quickly as possible, you can put your laptop to sleep or shut it down while it's charging. Doing this means it won't need to keep the screen turned on or use any system resources to run the OS.
Generally, charging after 70 or 90% is noticeably slower than when charging a laptop from zero. This is because most modern chargers ramp down charging speeds when close to full to preserve battery health in the long term. However, it's important to note that you shouldn't run your battery until it completely dies, nor should you keep your battery's charge full all the time since doing so can negatively affect the battery's health in the long run. Additionally, some manufacturers state that you should keep your battery between 40% and 90% charge to keep its health in good condition.
We only run each battery test once. Although we acknowledge this has the potential to skew results, we take into account the manufacturer-listed battery life and charge time, as well as our test results from laptops with similar specs, to help determine whether a test result is anomalous. Our results are best interpreted as standardized comparisons among models rather than being accurate estimates for every type of web browsing or gaming workload. Battery life varies greatly depending on your usage.
Depending on what you use your laptop for and how you use it, the battery life you get can vary greatly. Having a battery that not only lasts long but charges quickly as well is important for people who are constantly on the move or don't always have a reliable power source. You should get a model that scores well in this regard if that's important to you. That said, there are some easy tips and tricks you can take to increase battery life without sacrificing performance or usability, like lowering your screen brightness, turning off lighting effects, and optimizing the applications you use.