Symptoms
- Phone charges very slowly or barely at all when connected to a laptop or desktop
- Charging works fine on a wall adapter but not on a computer
- Battery percentage may even drop slightly while connected and in use
- A 'charging slowly' message appears on the notification
Likely causes
- CommonStandard USB ports on computers output much less power than wall chargersMany USB-A ports on computers are limited to around 5W, far below a phone's fast-charging capability.
- PossibleThe port is set to data transfer mode rather than charging modeSome connections default to a mode that prioritizes data over power delivery.
- PossibleThe computer is in sleep mode or its USB ports are power-limited in that stateSome computers reduce or cut USB power entirely when asleep or off.
- PossibleA USB hub without its own power source further limiting available currentPassive hubs split limited power among multiple connected devices.
What to do
- Use a wall adapter instead of a computer USB port whenever you need to charge quickly.
- If you must charge via computer, plug directly into the computer rather than through an unpowered USB hub.
- Check the phone's charging notification for a 'charging slowly' message, which confirms this is expected given the power source.
- Make sure the computer isn't asleep or in a low-power state, which can reduce or stop USB power output.
- Use a USB-C port if the computer has one, since these often supply more power than older USB-A ports.
- Avoid actively using the phone for demanding tasks while relying on a computer for charging.
- Treat computer charging as a backup option rather than a primary charging method.
- If even a computer's higher-power USB-C port charges very slowly, check the cable or phone's charging path instead.
When to call a pro
This is expected behavior from a lower-power source and doesn't need any repair.
Safety
Generally low risk
Generally low risk for a careful person. Stop if anything looks different from what this guide describes.