Charger performance changed after an update? Test it

Your device used to gain charge while you worked, but after a system update it stays level or drains while plugged in. That does not automatically mean the charger has failed. The update may have changed power settings, or your device may be drawing more power during the work you are doing.

Use the Charger & Cable Test to compare charge rate while the device is in use. It reports the change as percent per minute, which helps you check whether the same charger and cable behave differently after the update.

Test the charger while you use the device

1. Open the Charger & Cable Test on the device you want to check. The test appears only if your browser reports battery information, which is usually the case on laptops, tablets, and phones.
2. Connect the charger and cable you normally use. Keep the device on a hard, uncovered surface, and note the battery percentage and whether the device reports that it is charging.
3. Use the device for a few minutes in a typical way. Keep the screen brightness, open apps, and workload roughly the same as they were before the update. Avoid starting a demanding game or stress test just to create a load.
4. Watch the reported charge rate in percent per minute. Write down the rate, battery percentage, charger, cable, and what you were doing. If you have a record from before the update, compare the two under similar conditions.
5. Repeat the check with the screen off or with fewer apps open. Then, if available, try another compatible charger or cable separately. Changing one thing at a time makes the comparison useful.

Do not compare a reading near full charge with one from a nearly empty battery. Charging often slows as the battery fills. For a fair check, compare readings at similar battery percentages, preferably in the middle part of the charge rather than near 100 percent.

What the result means

The device gains charge during normal use

The charger is supplying enough power for that workload at the time of the test. If charging still seems slower than before, check the actual battery percentage over a longer period and compare at a similar starting level. A small percent-per-minute reading can be normal when the device is close to full or actively working.

The percentage stays about the same while you work

The charger may be covering the device's current power use without adding much charge to the battery. Try the same charger with the screen off and background apps closed. If the battery then rises more clearly, the workload is using much of the available power. This result alone does not prove that the charger is defective.

The battery loses charge while plugged in

The device is using power faster than the charger is providing it, or the connection is intermittent. A heavy workload, a low-power USB port, an incompatible charger, or a damaged cable can cause this. If the same charger charges normally with the screen off but not during light use, check the workload and the device's power settings first.

The reading changes when you swap a cable or charger

That points to a difference in the power supply or connection. A USB-C connector does not guarantee that every cable and charger supports the same charging speed. Some combinations provide basic power but do not support the faster charging mode your device can use.

The tool does not show a battery or charge rate

Your browser or device may not expose battery information to web pages. This is not evidence that the charger has failed. Try a supported browser on a laptop or tablet that reports battery status, or use the device's built-in charging indicator for a basic check.

How to fix a slower charge

1. Check the outlet and connection. Plug the charger directly into a working wall outlet, if practical, and seat both ends of the cable firmly. Look for a loose connector, bent plug, or damaged cable. Stop using a cable or adapter that is visibly damaged or unusually hot.
2. Reduce the workload for a comparison. Close demanding apps, pause large downloads, and lower screen brightness for a few minutes. If the battery begins rising faster, power use during your normal activity is part of the difference.
3. Check the charging limit. Some devices pause charging near a chosen limit, such as 80 percent, to reduce battery wear. On Windows 11, check Settings › System › Power & battery and the battery or charging utility supplied by the computer maker. On macOS, check System Settings › Battery for battery optimization options. On iPhone, check Settings › Battery › Battery Health & Charging. Android menu names vary by manufacturer, but look in Settings › Battery for charging optimization or a charge limit.
4. Restart the device after the update. A restart can finish applying system and power-management changes that are waiting to take effect. Then repeat the comparison at a similar battery percentage.
5. Check the power mode. On Windows 11, open Settings › System › Power & battery and review Power mode. On macOS, open System Settings › Battery and review the available energy options. Return any recently changed setting to its previous value, then test again.
6. Install device-specific updates. Check the computer or phone maker's official support instructions for power-management or charging updates for your exact model. Avoid installing drivers from unknown download sites. If the problem began immediately after a system update, record the update date and charger details before contacting support.
7. Compare a known-compatible charger and cable. Use one that meets the device maker's requirements. Test the charger and cable separately where possible, since replacing both at once will not tell you which part changed the result.

When the charger or battery may be faulty

If the device repeatedly loses charge while idle with a compatible charger, and a different known-good cable or charger makes no difference, the issue may be in the device's charging port, battery, or power circuitry. Check whether the plug fits loosely or charging starts and stops when the device is still. Do not bend or hold a connector at an angle to keep it charging. A damaged charger or cable should be replaced, while a built-in port or battery problem may need manufacturer service or a repair shop.

Why one test reading is not a wattage measurement

The Charger & Cable Test reports battery change as percent per minute, not the electrical power in watts. The result also depends on battery level, temperature, device activity, and charging limits. Use it to compare the same device under similar conditions, not to certify a charger's advertised wattage. The update may have changed what the device is doing while plugged in, so a controlled before-and-after comparison is more useful than a single reading.