Do-it-yourself powerbank for 21700 batteries

#powerbank #diy #gadgets
The powerbank uses two 21700 lithium ion batteries sourced and welded together by the user. It looks good, compact, and performs well. However, as total amount of mAh output depends on the batteries inside, so wise choice of a decent pair is a must. In short, case, good, batteries, bad.

DIY kit from Aliexpress:

Spot welder:

[ericklein]

Is there any warning about the powerbank requiring high discharge cells to safely handle the high current draw from the boost converter? If there's really a 66W output that's nearly 10A per cell.

[ediik]

i had 2 INR21700-40T from a project left and wanted to Build this Powerbank... it seems taht the Charging Curcuit only recognizes 2500 mah cells... anybody else with this problem_?

[marciozomb]

How can the powerbank deliver 9v/12v from PD with a 3.7v cell? They are connected in 2P right?

[curits]

is the amp does not matter? any battery atleast 3.7v will do?

[deraid]

10000 is max its only 2pcs, and they have less capacity than 5A usually more like 4a so its 8000mAh and its useless

[ericklein]

Well those are some obviously BS cells. 6000mAh? They surpassed Samsung, LG, Sony, Panasonic, Molicel, Lishen, EVE, and BAK! The Samsung 50S is already irrelevant!