Just discovered the Battery Mooch channel on YouTube that provides a great deal of information on LI-ion batteries in a easy-to-understand format. The channel is geared for vapor users but is a also great source for new flashlight aficionados.
Mooch also has a blogwhich I've seen referenced in this forum.
He’s been on youtube for some time now. I love how he uses the white board and explains things so a non-technical person can understand. Here is his setup The New Testing Station - YouTube