Symptoms
- Devices show 'not charging' when plugged into the power bank
- Power bank's own indicator lights show a charge but nothing transfers
- Charging works but is extremely slow
Likely causes
- CommonPower bank itself needs chargingAn empty power bank can't output power even if it looks fine externally.
- CommonWrong or damaged cableCharge-only cables or damaged ones can prevent power transfer.
- PossibleOutput port not matched to the device's needsUsing the wrong port or a low-output port can fail to charge power-hungry devices.
- PossiblePower bank battery degradedLike all lithium batteries, capacity and output drop with age and charge cycles.
- Less commonOverheat protection triggeredSome power banks shut off output automatically if they get too warm.
What to do
- Charge the power bank fully using its input port before testing output again.
- Try a different, known-good charging cable.
- Use the highest-output port on the power bank for larger devices like tablets.
- Let the power bank cool down if it feels warm, then try again.
- Test the power bank on a different device to isolate the issue.
- Check the power bank's indicator lights against its manual for error codes.
- Replace the power bank if it consistently fails to output power after a full charge.
Tools and parts
Replacement USB cableSearch: “USB charging cable for power bank”
When to call a pro
If the power bank won't output power after a full charge with a good cable, its internal battery or circuitry has likely failed and it should be replaced rather than repaired.
Safety
Generally low risk
Generally low risk for a careful person. Stop if anything looks different from what this guide describes.