I'm quite new to 18650 batteries (having just learned about them a few months ago, when I first got a generic "Cree XML-T6" flashlight that used 18650 batteries.
I've since then been reading and learning some stuff about them from this site and others.
In the below excerpt for LG HG2 3000mAh 18650 spec sheet I saw online:
I have 2 questions:
1) the spec sheet seems to indicate 2 "nominal" charge currents for this battery -- 1.5A, and also 1.25A.
I'm just curious why there seem to be 2 different "nominal" charge currents (I'm also checking Samsung INR18650-30Q spec sheet and it only lists 1 "nominal" or "standard" charge current for that model, which is 1.5A.
2) there is an "end" voltage in the above spec sheet and it indicates 2.0v; based from reading a few 18650 spec sheets online, I notice that most higher capacity 18650 (eg. 3000mAh or more), will get their nominal capacity if doing a discharge rate of 0.2C and cut-off voltage of 2.50v.
But in the above case, for the LG HG2, what does the 2.0v "end voltage" mean? Maybe it's the "end voltage" when doing "high drain" of 20A?
But when doing 0.2C discharge, the cut-off voltage should be 2.50v (for testing capacity purposes)?
~~~~~~
From reading various stuff about 18650s, I learn that while it's best to keep cut-off voltage at 3.0v to prolong the life cycle. But when doing capacity testing purposes, cut-off at the lower voltage of 2.50v (for higher capacity cells) would be needed. I notice for lower-capacity cells (eg 2000mAh-2600mAh), it seems the cut-off voltage (for capacity testing purposes) seem to be 2.75v in many cases.
Since at the moment, I could only get my hands on "fake" or "mislabeled capacity" 18650s locally. (I haven't found branded 18650s yet locally; Banggood and Gearbest does not ship to my country; and I'm still waiting for my AliExpress order of a few branded 18650s to arrive..) I ordered a few of each brand (Samsung INR18650-30Q, LG HG2, Panasonic NCR18650B), and when they arrive, I'd like to do some capacity testing of them to verify that they're really the capacity indicated (and need to follow manufacturer spec sheet if I want to have as close as the stated nominal capacity)