Power bank charging changed after an update?

Your phone or laptop started charging more slowly from a power bank after a system update. The bank may be fine: the device could be using more power, charging limits may have changed, or the new reading may simply reflect a different battery level.

Compare charging under the same conditions before replacing anything. TooLab’s Charger & Cable Test measures charge rate as a percentage per minute, so you can compare the power bank, cable, and another charger on the same device.

Compare charging with the power bank

Open the Charger & Cable Test on the device you want to check. It appears only if your browser reports a battery for that device.
Use a battery level well below full, ideally around 20% to 70%. Charging often slows as a battery gets close to full, so readings taken at very different levels are hard to compare.
Connect the device to the power bank with the cable and port you normally use. Follow the test’s on-screen instructions and note the charge rate in percent per minute.
Repeat with a wall charger or another known-good power source. Keep the device at a similar battery level and leave the screen and active apps in the same state for each measurement.
If the power bank has several output ports, test the port you normally use and, if appropriate, another port. Use the same cable for both comparisons.

Wait for the reading to settle before comparing. A brief change is not enough to identify a fault. If your browser does not show a result, that means it cannot provide the battery data the test needs, not that the power bank has failed.

What the result means

The power bank and other charger have similar rates

The power bank is probably charging the device normally. The apparent change may come from battery level, screen use, background activity, or a new charging limit. Repeat the comparison when the device is cool and the battery is at a similar level to your earlier test.

The power bank is slower, but the other charger is normal

Focus on the bank, its cable, and the output port. A cable can still provide power while limiting the charging rate. Try another suitable cable and port, one change at a time. The test measures how quickly the battery percentage rises, not the power bank’s exact wattage or whether its label is accurate.

Both chargers are slower than before

The device may be using more power while it charges, or the battery may be warm or near full. An update can also change system activity or charging behavior. Repeat the test with the screen off, close demanding apps, and compare at a lower battery level before concluding that a charger is faulty.

The rate moves up and down

Small fluctuations are expected. The device adjusts charging to manage temperature and battery condition, and the percentage display updates in steps. Look for a consistent difference across repeated comparisons, not a single changing number.

The device stops charging or shows a limit

Check whether a charge limit or optimized charging feature is holding the battery below full. These features may pause charging or slow it based on the device’s settings and usage pattern. A limit is not evidence that the power bank is defective.

How to fix it

Check the cable and connection. Unplug both ends and reconnect them firmly. Look for lint, bent contacts, or damage, and try a different cable that supports charging for your device. Do not force anything into a port.
Try another power bank port. Some banks have ports with different output capabilities. Check the labels on the bank or its manual, and compare ports using the same cable and device conditions.
Reduce device use during the comparison. Turn off the screen and stop games, video, navigation, or large downloads. These activities use power while charging, which can make the percentage rise more slowly.
Let the device cool. If it feels unusually warm, disconnect it and let it cool naturally before testing again. Do not charge a hot device under bedding or in direct sunlight.
Review battery and charging settings. On Windows 11, open Settings › System › Power & battery and check the power mode and any manufacturer charging utility for a battery charge limit. On a Mac, open System Settings › Battery and review battery options. On an iPhone, check Settings › Battery › Charging or Settings › Battery › Battery Health & Charging, depending on your iOS version. On Android, look under Settings › Battery for charging optimization or a charge limit; names vary by manufacturer.
Restart and compare again. Restart the device, then repeat the test with the same bank, cable, port, and approximate battery level. If the result changed after an update, this helps separate a temporary software issue from a repeatable charging difference.

When the power bank or cable may be faulty

If the same device charges normally from another source but repeatedly charges slowly or disconnects from the power bank, test the bank with another compatible device and a known-good cable. If the problem follows the bank across devices and cables, check its instructions and warranty. A cable that fails across several chargers should be replaced. Stop using any bank or cable that is swollen, damaged, unusually hot, or smells burnt.

Why a percentage rate is not a wattage reading

The test reports how quickly the device’s displayed battery percentage changes. It does not directly measure electrical power in watts. Battery size differs between devices, and the device controls how much power it accepts based on temperature, battery level, and charging rules. That is why comparing two chargers on the same device, at similar battery levels, is more useful than comparing percentages across different phones or laptops.

For a fair comparison, write down the battery level, cable, bank port, and whether the screen was on. Repeat each setup once under the same conditions before making a decision.