Basically I would like to know at what current the charge port is charging the cell at.
Anyone know how to go about testing this?
Read the current between the charge circuit & the battery with a DMM set to amps. Similar to reading current at the tailcap of a flashlight.
White light or device is it?
If it is usb you are talking about, looks at this: https://budgetlightforum.com/t/-/25415
Nice, I missed that thread! Another thing I need to buy. 
I was thinking something more along the lines of some setup with aluminum foil and whatnot like checking a charger with a DMM, but this is way easier.
… Whoops. I guess I was again making it out to be more complex than it actually is. Hah.
It’s a single 18650 flashlight with a built in charge port in the head. I can reveal the model in a few days (maybe today if my tests go by smoothly).