Actually, the X100 head is not 389g.
I measured mine to be 485g. Anyway, not too far off i guess.
But alright, lets take it that the TR-J20 head is indeed 1279g in mass for a moment, 2.6X more than the X100 head. And surface area is 2 times as what you have mentioned.
Actually i just returned to the hobby and was wondering with all these new efficient emitters if we are now able to hit 10k lumens plus for a longer duration now. There is no need to be indefinite (4 x 18650s would go empty anyway :D). It could be 30 minutes as you previously mentioned, it could be even lesser. Just wanna find the “spot”, ie 10000 lumens 8 minutes, 1000g.
Well if the TR-J20 were to be running at 7000 lumens, then yes for sure the lumens efficiency is going to be better. But i believe the original point is whether or not a light could be doing 10k+ lumens for a good period of time, be it 30 minutes, indefinitely etc. If not, maybe we can shoot for lower durations, which is more practical.
I also have a quest, if practically possible, to find a good 10k+ lumens light which can operate for longer durations, be it 15 minutes, 30 minutes etc.
Yes the TR-J20 uses more emitters (12 x XM-L), but actually in this case it goes like this.
X100 = 7 x XM-L = 7000 lumens max driven (see Match’s output test in 1st post), 78W.
TR-J20 = 12 x XM-L= 12000 lumens max driven. 133W,
The “lumens efficiency” is the same, and wattage scales up accordingly.
Well I believe it could still be possible if the light is on a tailstand and it is outdoors in a cold sub-zero climate with some wind though. The light could start off at say 0 deg C with ambient at –15 deg C, and the temperature delta between the head and ambient would be larger, the convection heat dissipation would be better as well.
I measured 67 deg C at the head and close to 50 deg C for the handle at just 7 mins for the X100 (485g) for 7k lumens, and remember this is with a small fan blowing at it. Ambient was at 30 deg C (my country ughh!). At maybe around the 15th minute (I didn’t get the exact time stamp) I got 82 deg C for the head and still rising. This is only possible as i am running direct drive, no driver electronics to poof.
2.6X more mass and 2X more surface area. 1.7X higher wattage.
Impossible to handhold at 50 deg C without gloves. And probably starting to risk the driver electronics which is going to be operating much higher temps.