Another Cheap DIY Powerbank

EDC Gear for Flashlight Carriers USB Power Devices
1


When I bought it the price was $1.71, they’ve raised it to $2.45 by now.

It has a nice aluminium casing with screw on cap. Plastic sleeve with electronics and slot for battery inserted into it (image from review on GB):

IC has no markings on it.
Charging cut off: 4.21v
Discharging cut off: 3.03v
At about 3.2v the blue led will start flashing.
Power bank wont start charging if battery voltage is under 3.4v
Based on amp draw from USB it uses CC/CV charging, draining 0.7A/4.6V at the start and 0.05A near the cutoff.

2

How are the threads on the body and cap?

3

I would say they are reasonable for the price. They are quite thin and feel somewhat rough, but do the job.

4

How is it holding up?

5

This is an 18650 battery right? What’s the real capacity? I doubt it holds 3500mah.

6

I am a newbie when it comes to power banks - can the cheap ones be charged and discharged at the same time?