Is your power bank blinking but not charging? Here’s what to do

Is your power bank blinking but not charging? Here’s what to do

The LED Indicator lights and their functions

Most power banks have 4 small blue LED lights to provide you information about the state of your power bank. When you connect your power bank to a power outlet to load it, one of the LED lights will blink, indicating that the power bank is taking up the charge. 

While connected to the power source, the power bank LED lights indicate the charge taken up by the power bank:

  • 1st light blinking means it is charged between 0%-25% 
  • 2nd light blinking means is charged between 25%-50%
  • 3rd light blinking means it is charged between 50%-75%
  • 4th light blinking means it is charged between 75-100%.

When you check the power bank and you see 4  LED lights glowing steady, it means that the unit is now fully charged. 

When you connect your mobile phone to the power bank, it starts to charge it, the LED  lights on the power bank indicate the following: 

  • All 4 lights are blinking means it has between 75%-100% charge remaining.
  • 3 lights blinking means it has between 50%-75% charge remaining.
  • 2  lights blinking means it has between 25%-50% charge remaining.
  • Only 1 light blinking means it has between 0-25% charge remaining. At this point, you should disconnect the mobile phone, as you should not discharge the power bank completely, as it may damage it if you do it frequently.

Suppose you are planning to go on an important business trip. You pack everything up,  charge up your phone, laptop and put the power bank to charge overnight. The power bank’s light is blinking and you go to sleep peacefully. But when you check in the morning it has not charged at all. Or it is charged halfway or somewhere in between, with the lights showing it is not yet fully charged. Something is not right. Is the power bank failed completely or is it something trivial? 

Possible causes and troubleshooting checklist

The problem may be a minor fault that can be easily taken care of, or it can be a serious issue that requires professional repair. It could be one of the following problems:

1. It may a bad power connection 

It may happen that you simply didn’t fully insert the power plug in the socket and after some time it came loose and the power got disconnected. Check the plug and see that it fits the socket snugly. Also, make sure that the power connector on the power bank is inserted fully in its socket. If one of the LED lights on the power bank starts blinking then you have solved the problem. 

3. The power cable could be defective

If the connections are snug and the power bank is still not charging then it is possible that the power cable is bad. Simply change the power cable and try again. Make sure that you are charging the power bank from a main electric power outlet and not a computer, as sometimes the output voltage from a computer USB port is not sufficiently high for the power bank.

4. The charger could be faulty

Check for the possibility that the charger has gone bad. Try a new charger or connect the power bank to a USB port of a computer to test it. If this works then you can be certain that the charger is faulty and you should replace it.

5. LED indicator lights went bad

The LED lights are quite reliable and have a long life, so it is unlikely that they all may fail. However small, there is a chance that the power bank is working fine, but just the lights are faulty. You can test this by connecting the power bank with your mobile phone and if it is charging it,  then that may be the problem. LED indicator lights give important information about the power bank, so you should get it repaired from a professional.

6. The power bank battery died

If your power bank does not appear to be getting charged as no lights turn on when connected to a power source nor it charges your mobile phone when connected to it, then it is likely that the power bank has suffered an internal failure. 

If the power bank suffered a hard shock like a fall or was left in a hot environment for a long time, there is a possibility that its internal circuits have failed. 

If you have used your power bank quite frequently, then it is possible that the batteries have completed their life. Power bank batteries have a life of 300 to 1000 power cycles, depending on the brand and model. 

In all such cases, the problem is serious and the power bank should be repaired professionally.

Never overcharge or fully discharge Lithium-ion batteries 

Lithium-ion batteries are designed in such a way that they are charged to just below their full capacity before they attain the full voltage. They can discharge up to a certain voltage below which its internal circuits stop further discharge to protect the batteries. Overcharging or fully discharging reduces the life of the Lithium-ion batteries.

If the power bank batteries are totally discharged due to any reason and the voltage falls below a threshold, it may be difficult to recharge it. In such cases, give it more time, connected to a power source, until it slow trickle charges to a certain threshold level then starts its normal charging sequence.

Some other helpful hints to keep your power bank healthy

  • Always use the cable supplied by the vendor or any other short length good quality USB cable.
  • Avoid charging the mobile phone with the power bank while loading your power bank from a power outlet at the same time.
  • Avoid leaving your power bank in a hot place such as a parked car in summer.
  • Only charge devices that are intended to be used for that model of the power bank.


In case your power bank is not working properly but it can be fixed by changing the cable or the charger, then do it yourself. However, if the issue persists, you should get it repaired by a professional. Do not try to open the case of the power bank and try to repair it yourself, as it will void a valid warranty.