I fully agree, this should make things clearer for many people. Drodz, what would the impact be on a 18350 UF using LR?
As I don't have an UF 18350 I'll have to look up the mAh on it but then I'll go through the math on it...and show the steps so that hopefully you can see how it all works and is all related..
ok...first lets look at the c raings on batteries (we'll use that later)...we can assume the c raing on a Li-Ion battery is 1C unless otherwise denoted (AW Li-Ion are 2C, *fire brands are 1.5C)....
then there are the actual math problems we use:
for amp draw..... it's voltage/Resistance
for wattage........ it's voltage* voltage/Resistance
and for max drain rate on the battery it's mAh * C rating/1000 at 60min/C rating
so we have the 18350 battery and LR atty...
so amp draw... 3.7V/1.5Ω = 2.47A
wattage.... 3.7V * 3.7V / 1.5Ω = 9.13W
max drain of battery 1200mAh * 1.5C /1000 = 1.8A over 60/1.5C = 40min (so this is the fastest and highest drain you can put on the battery before damage to the cell.....note it's less than the amp draw of the LR atty at 3.7V (so the battery would be overstressed)
now for the rough time guesstimate... if you work that max drain rate kinda backwards you can find your C rate...and then divide 60min by that C rate to find out how long continuous that battery would theoretically last... by dividing the amp draw by the mAh rating to get C rating...
so 2470mAh (that's 2.47A) / 1200 =2.06C
60min/2.06C= 29.13min --> *60 (to get seconds) = 1747 seconds
of course that's on a new battery...since it's being overstressed that will eventually drop...
and since the battery # is an expression of it's size in mm ...ie 18350 is 18mm in diameter x 35mm long and the 0 denotes cylindrical cell...
I'd use a highdrain 16340 instead it's 2mm smaller in diameter and a mm longer (technically *since a protected Li-Ion cell will add 1-2mm to the length due to PCB, and the high drains are a safe chemistry LiMN so there's no PCB (so it's really likely a smaller battery)).... and you won't overstress it...granted it won't last quite as long between charges (about 801 seconds) but it'll give more oomph while operating too (which will likely shorten the length of your button presses)...
as an extra....the high drain 16340 is 550mAh..but with an 8C discharge rating....so...
550mAh * 8C /1000 =4.4A over 60min/8C = 7.5min
hence why it's called high drain because you can safely draw 4.4A from it in 7.5min before any damage to the cell...and it's substantially more than the 2.47A draw of the LR atty at 3.7V..
as far as the time on that high drain:
2470mAh/550mAh =4.49C ...so...60min/4.49C= 13.36min or 801 seconds
an 18650 battery overcomes the amp draw problem by sheer mAh rating...
AW for example 2200mAh * 2C/1000 = 4.4A in 60/2= 30min or 1800 seconds
(I used the AW because there's so many of the UF 18650 batteries...and well following the flashlight people so many of the *fire batteries are a crap shoot of QC (expecially the 3000mAh red and black ones (they test out to be more like 2400mAh))...so the math gets really unreliable on them)