user60422: I have used many Arduino boards with adapters and other power supplies. While connecting with a powerbank for portable projects I have noticed that the power goes off after a couple of seconds and then turn on again after sometimes. Why this is happening with power bank?
I have used following powerbanks:

Basus
Xiaomi


user69592: Most USB powerbanks will automatically turn off if there is not a minimum current draw to keep them turned on.  The Arduino is obviously drawing current below the limit for the devices you have.
A couple of options:

Add some additional load to keep the powerbank on indefinitely.  Of course this may waste power but that's part of the price to pay.
Find a power bank that is less sophisticated.  I have one with a manual on/off switch.  It powers the Arduino just fine until it runs out of power.
Find a different powerbank that has a lower threshold for staying on.  Some vendors give you this spec and others don't.
Modify the powerbank to stay on.  I'm not sure there is a general way to do this but you might experiment with it and see.


60422: <p>I have used many Arduino boards with adapters and other power supplies. While connecting with a powerbank for portable projects I have noticed that the power goes off after a couple of seconds and then turn on again after sometimes. Why this is happening with power bank?<br />
I have used following powerbanks:</p>
<ol>
<li>Basus</li>
<li>Xiaomi</li>
</ol>
 69592: <p>Most USB powerbanks will automatically turn off if there is not a minimum current draw to keep them turned on.  The Arduino is obviously drawing current below the limit for the devices you have.</p>
<p>A couple of options:</p>
<ol>
<li>Add some additional load to keep the powerbank on indefinitely.  Of course this may waste power but that's part of the price to pay.</li>
<li>Find a power bank that is less sophisticated.  I have one with a manual on/off switch.  It powers the Arduino just fine until it runs out of power.</li>
<li>Find a different powerbank that has a lower threshold for staying on.  Some vendors give you this spec and others don't.</li>
<li>Modify the powerbank to stay on.  I'm not sure there is a general way to do this but you might experiment with it and see.</li>
</ol>
