This actually looks quite obtainable. Let’s look at the math:
Stock BTU is 3000 lumens, 135kcd. This equals 45 candela for every lumen.
Modded BTU with increased amps and lower resistance estimate is 4000 lumens, 200kcd. This equals 50 candela for every lumen.
What does this mean? Well, since there’s no actual change in shape between XML and XML2, if it did put out 4000 lumens, it theoretically would have roughly around 180kcd. Unless there’s some way you could change the ratio of throw to total output (by dedoming), to achieve 200kcd you would have to increase the lumens to 4444.
These are just rough calculations based on my calculated estimates. But if you could increase the amps to the LEDs I don’t see why it’s not possible, but 200kcd would require high current! Definitely over 4.5amps each emitter.
I already got 190+ kcd and 3,900+ lumens on a mod'ed DRY driver Shocker, so, really close, and I'm thinking my kcd measurements may be low because I'm measuring at only 4.3 meters. Also, general rule (from real, many upgrades) -- 20% increase in lumens means 40% increase in kcd - now don't ask me why, but it's proven in measurements done by me and rdrfronty. Also, this could be only for thrower designed lights, not sure.
Also, we are getting 180 kcd out of 3,600-3,700 lumens or so on the Shocker, again, measured by more than one person.
There's no math, just actual measured results. But, you have to consider what kcd is - it's very different from lumens (brightness, total light output). kcd is not distance directly, in fact if you double kcd, you don't double the distance, it's actually a lot less than double. It's the measurement of brightness at one small measurable point, back computed to 1 meter. So many say 10% increase in lumens isn't noticeable, and 10% increase in kcd would be less noticeable because it's less than 5% increased in rated distance (632m to 663m for example, going from 100 kcd to 110 kcd).
If you have an XML and xml2 in two identical reflectors, and both had 800 lumens would the throw be the same?
If you don’t mod it, (and for arguments sake assume that my previous calculations were correct) and decrease the output from 3000 lumebs to say 1000 lumens, then the kcd would just be 45kcd… Right?
My entire reasoning is based on that premise. I will measure this next week to confirm, unless someone else volunteers (its a 2 min experiment).
My two personal examples of the XM-L2’s offering a higher percentage of Kcd vs lumens -
TN31 XML U2 - 1075 otf at 30sec
122Kcd
TN31 XM-L2 U2 - 1275 otf at 30sec (18.6% increase in lumens)
157Kcd (28.6% increase in throw)
BTU XMl U2 - 2975 otf at 30sec
132Kcd
BTU XM-L2 U2 - 3670 otf at 30sec (23.3% increase in lumens)
181Kcd (37.1% increase in throw)
All these were done with the same batteries and same meter before and after testing. Not sure why, but XM-L2’s to appear do be better throwers than XML’s.
I was showing mine off all week. My son and daughters friends were amazed. It’s like turning on a streetlight in your backyard. Any light that smokes my TN31’s to me is pretty damn mean. This BTU is mean.