Well, I monitored the charge cycle until voltage approached 4.20, then began getting nervous.
I checked my other NCR18650b on my DMM that
EnerPower+ 18650 2500mAh (Blue) 2015
Button top version
"Li-ion" is an all-encompassing term for several types of rechargeable batteries, not a specific chemistry. LiCo, IMR, Lithium Phosphate etc..Up All Night Today, 02:58 AM
I purchased an inexpensive single cell 'Vktech® Portable Power Bank Backup External Battery Charger' from Amazon, and it arrived today