How to power up Lolin NodeMCU v3 using rechargeable batteries?
As I understood, I can feed the NodeMCU with 3.3v to power it up
How can I do that?
I'm a beginner so forgive me about my faults
Thanks 
A NodeMCU should run about three days on a 10Ah powerbank (USB connection).
You might have to try a few. Some could switch off (sleep) after a few seconds.
Leo..
Use a LiPo battery and LDO regulator.
Make sure the regulator can supply the required >200 mA spikes when using WiFi.