I am new, have spent some hours, but not found a “Beginners guide/tutorial/FAQ flashlights”, text and/or video to understand all the diff. tech. stuff like lumen, CRI, SST, thrower, emitter, battery sizes and mAh etc.
I have been on several manufacturers websites. I have not found any FAQ.
There is https://flashlightwiki.com/
It’s not very active or very up to date but the basics should be covered there…
thank U, looks ok for a start
Crossposting. 
yes, crossposting, warum nicht ? super, vielen Dank
CRX: wow, thanks a lot, some people (and U are one of them) spent a lot of time making great posts !
Understanding the ANSI FL1 Standard
Interesting that article says CPF is the most active forum. I was thinking recently that BLF seems busier now.
This youtuber usually goes into depth with his reviews,he’s a member here as well.
Kevin Z: Thanks, he is new to me
I said the wiki was outdated.
Darn, Jack beat me to it.
This is a deep dive into batteries: https://batteryuniversity.com/