I have a 1 1/2 Monte Pero coffee jars full of these cells. I need to source some of these SMD resistors first, but it looks like if to keep it 24/7 the charge current will drop down to 200mA quite fast._
It's risky as the bench power supply may not be accurate enough to limit the voltage output. You can get a lithium battery charger boards (TP4056A based works a treat) from aliexpress dirt cheap and feed 5 volts from power supply to the board._
Little clarification about different color rings: UR18650A's manufactured in Korea has white ring, but ones made in Japan has purple. Got both out of two Dell J1KND battery packs that stated the cell origin._
I think the problem with pouch and prysmatic cells is that there are too many different sizes to be useful to reuse unless you want to make USB power banks out of 1-8 cells or a mosaic out of cells. Here's my start though.
Have 7 of these with R2112 serial number, charged 3 with one UR18650F mixed in a 4 cell charger (usb power bank M09)and UR18650A-s went scolding hot at 500mA charge current while been half way from fully charged._