Why do some laptops never charge 100%?

Starting your day with 100% laptop battery may seem like you’re ready to take on anything, but there may be more than one reason why your laptop isn’t hitting the mark. If hours of charging leave your battery at a much lower percentage than you expect, your machine probably has protection in place to prevent overcharging. Just like charging an Android phone to 100% can harm it, the same can be true for your laptop.

Some battery issues can prevent a battery from charging, but one of the first things you should check is if your laptop has battery health settings that can prevent a 100% charge. On a MacBook, for example, this feature is called Optimized Battery Charging, while Windows offers something similar called Smart Charging (although some PC brands may use a different name). Essentially, these features help preserve the lithium-ion battery in many laptops, as constantly charging to 100% can degrade it more quickly.

Of course, other daily habits can also destroy your laptop battery, but checking if your laptop has additional battery features can be a good place to start. We’ll show you several ways to disable this feature, but we’ll also look for other common signs that your battery is failing. Also check your owner’s manual to see what it says about your battery.

Naturally, a hardware or software issue can affect the health of a battery, but your laptop can also stop charging on its own. For example, Optimized Battery Charging (introduced in macOS Catalina) on a MacBook will delay charging a battery past 80% until “the time you need a full charge.” Users can also set load limits on macOS Tahoe 26.4 or later. This means you may not reach 100% at the exact time you want, but you can turn this feature off.

Here are the steps (macOS 13 or later):

1. Select System Settings from the Apple menu.

2. Choose Battery from the sidebar.

3. Select the Info button next to Battery Status or Charging.

4. Turn off optimized battery charging. Apple will give you a few options.

5. You can also check if a load limit is enabled from this menu.

On Windows machines, this feature is called Smart Charging and handles this charging juggling act for you. However, it can also prevent you from reaching 100%. Windows should display a battery icon on the right side of the taskbar to indicate that the feature is running (you can also see it in the Power and Battery settings). There’s an easy way to test the battery health of your Windows laptop, but check your owner’s manual or manufacturer’s website to learn how to turn off smart charging. Keep in mind that your laptop may not intentionally reach 100%.

If the smart/optimized charging features are disabled and you’re still having issues, it might be time to run some simple diagnostics. You should also know the signs that your laptop battery is dying. Start with a simple reboot to eliminate minor bugs that might prevent your device from fully charging. Next, inspect your power adapter and charging port for any physical damage.

If you can, try the charging accessory with another device to see if the charger works. With Windows, you can try updating your battery drivers.

Here are the steps:

1. Open Device Manager.

2. Expand the Batteries section.

3. Right-click Microsoft ACPI Compliant Control Method Farm.

4. Choose Uninstall Device. You may need to confirm.

5. Restart your device.

You can also check for BIOS and firmware updates that your device may need. You can also check with the manufacturer if your device has battery diagnostic tools; Calibrating the battery can also help.

To calibrate a battery:

1. Load the device as high as possible and charge it for two hours afterwards.

2. Unplug the device and use it until the battery runs out.

3. Save any progress when you receive a low battery warning.

4. Leave the laptop running until it goes to sleep.

5. Wait five hours, then charge your laptop continuously for five hours.

If your laptop battery shuts down randomly or drains quickly, it may be time to replace it.