Another good example is the X80 and X80GT. Weighs only 330g. I guestimate 260g in the head, but can maintain 4000 lumens for 1.7 hours.
Extrapolating would yield 20,000 lumens continuous for 1,300g head. Again in reality it’s not an apple to apple comparison, but I do believe with the right drivers and emitters, it would not be difficult for the TR-J20 to sustain 10k+ lumens.
Actually we do not need to go the X80/GT route.
I did a search, think we already have the answer with the 70.2 and underdriven in the top dogs with Acebeam X70 and Imalent MS12. I am not sure if active cooling is needed for your said 30 mins duration, but i believe it’d have kicked in?
We’d definitely need a light equipped with 12 x XHP 70.2 (basically 48pcs of XP-Ls 
).
The X70 is 1.819kg with battery pack (prob around 1.4kg empty) and a 119mm head. (TR-J20 91mm for comparison, both are somewhat similar league i guess)
The MS12 is 1.740kg with battery pack and 129mm head.
6 watts would give you approx 1.1k lumens from each 70.2 at those drive levels.
Another problem is that these lights are also probably driven to very very hot levels, so hot that it’s practically unusable without a sling. In a review i saw, the X45 (4 x XHP 70.2) at 700g hitting thermal regulation at 167 deg C or 75 deg C at the head. That’s crazy.
4 pcs of XHP 70.2 is actually underdriven at 12k lumens, we need to go with more emitters to increase efficiency.
The BLF Q8 is doing 55 deg C head and body at 43 deg C is already close to being too hot to hold.
But if we are just talking about whether its technically possible and driver electronics wise, it’s ok to jam in more emitters into the 91mm head. Even the batteries are going to be a bit sketchy with the head that hot without active cooling…
So for sure the emitter choice + number of emitters is going to be key points.
PS. Actually in terms of practical use, my father in law and his workers for their commercial use in plantations/birds nest inspection have been using HIDs for many years (since 2010), though those metal can HIDs are more like 4000-ish lumens. Able to sustain half an hour no issue. I am wondering if current LED technology can do it. It probably can, just at a price. :money_mouth_face:
This is 700g and 4 x 70.2, 14k lumens ie driven at just a bit under the max capable 17.1k lumens as per datasheet. Quite interesting review.
I am wondering if anybody has done measurements in their review with the 12 x 70.2 X70 and MS12.
Go to 7 min 40 seconds. 167 deg F (75 deg C) at 3.00 mins, then it kicked down.
Gezuz, 540 usd for the Acebeam X70 and that’s on taobao. :innocent:
I am wondering if just for fun, getting 12pcs of those cheap Chinese 7070 emitters (sort of a copy of the real Cree XHP 70.2) and modding the TR-J20 reflector to fit would work for 12k lumens, with a suitable driver, of course. 
They are just 3 usd each on Taobao.
Nah….probably focus would be off. 
From what I read, the X80GT can maintain 4000 lumens and stay just warm. The DX80 at 10minutes in measures 135F in the head and 110F in the handle so very manageable.
Been thinking about it, so if it really takes 12 x XHP 70.2 and big/heavy hosts, what choice do we normal BLFers with real budgets really have, if we really want to go past the 5-digit lumens mark and do extended periods, be it 15 mins, 30 mins or 60 mins? Esp for folks like me having 30 deg C nights and not - 30 deg C in Canada/Norway so no assistance from a large temperature delta.
We do have a relatively cheap rmb 318 host on Taobao which i was able to bargain it down to. I believe we’d be able to get it till 268rmb / usd 38.6, as per 1688.com listing.
4 pieces (12 emitters) would run usd 154. You can use 16 x 18650 and each battery would not go above 5A i think, or you can run 8 cells with higher amp batteries.
4 x 458g = 1832g, and 4 times the surface area of 1 host.
Actual numbers measured by a BLFer. It’s a 6500-7000 lumens light, with a lumens drop after 30 seconds similar to a Sofirn Q8, in terms of thermal performance.
It just might be able to sustain running via just passive cooling even in the tropics, even though this is not a legit Cree XHP 70.2 Though you’d need to DIY an aluminum holder with handle for 4 lights or something.
If we just pump 3000 lumens or similar from each host, we’d get past 10k comfortably in total.
edit - opps, lousy mode spacing, 60% and 35. So it’s just 9200 lumens for 4 pcs at 35. Or 16k lumens at 60%, which is probably too high.
Ceiling bounce figures
It’s that high even with 12 x 70.2 and 10 minutes? And i suppose ambient temperature during testing was comfortably under my 30 deg C nights here? 
10 minutes @ 4000 lm
135 F = 57 deg C head
110 F = 43 deg C handle.
Yes that is exactly what i got with my BLF Q8 (above pics), 54 deg head = 43 deg at the tube, that’s the temperature difference we are talking about.
Ok, maybe we have a very different picture with regards to what manageable means.
For sure it’d hit well over 50 deg C at the tube once we go 20, 30, 40 mins. (if it can run that long)
43 deg C at 10 minute mark, at the handle for me (and still rising) is not really manageable long term, not roasting hot that you can’t touch it for over 1 second, but it’s not comfortable for me past 30 seconds. I have been testing both BLF and Sofirn Q8s for the past few nights bumping off the turbo thermal regulation, and it’s not comfortable for me or my sons for the Q8s.
The X70 would be different, with a separate plastic handle. So that could be an option to choose to, separate handle.
Of coz, those are just our personal opinions, others might have different “thermal” thresholds.
edit - oh, i know the reason already. 
You could change it to a plastic handle, perhaps.
No you misread, the X80 is barely warm from what I read. The temperature quotes were from Advance Knife Bro’s review of the DX80 not X80. I believe he tested it at Turbo and just let the thermal management kick in, which drops it eventually to between 7k-8k lumens and maintains that level for the entire duration. He did say you can management without gloves if it was in cooler weather so I assume the weather he is in is not cool. But I think 110F at the handle is not hot at all for high power flashlights.
I see……
Of course 43C/110F is still ok for very short periods of hand holding. Personally i think 43 deg C/110F at the handle is really too much for prolonged operation (20-30 mins) of the light?
That’s 43C/110F at 10 mins mark, it’d further rise to noticeably higher temps at 20-30 mins mark….i don’t know, 115, 120F? If there is a large temperature difference wrt ambient, then i suppose it wouldn’t rise much above that?
These comfortably close to 2kg lights with batts are not going to be light. Even with a 600g Q8 (400g + 200g batts), you’d need to apply some decent pressure on the aluminum tube in order not to let it slip. 43 deg C air temp 30 mins is endurable, but 43 deg decent pressure on a metal surface is really another thiong.
If it was a HID + sling or LED + sling like what my father in law and his workers are doing with their 65W HIDs for several tens of minutes of operation, it’s still doable I guess.
edit -
Ok, seriously just for fun’s sake (:D), i just ran my Q8 in Turbo and tried it out. 43-45 deg C temps. Short term is seriously ok….that i’d have to agree with you. But we really are talking like about 30 mins right?
I actually gave up at the 1-2 min mark, and now even while typing things out on the keyboard, my left hand is still feeling the “heat”.
And for that matter, I also just tried 46-48 deg C with my right hand with more turbo re-activations. If 48 deg C is manageable, you have my full admiration bro.
I was not able to endure 48 deg C for more than 15 seconds + decent pressure on the tube, it really felt like my hands were burning.
Trust me bro, you could actually try it in real life with any of your lights and see if 43-44 deg C on the IR thermometer, whether handholding with a good amount of pressure on the aluminum tube is comfortable or not once past that 1-2 mins mark.
Shucks….I might have very slightly “heat injured” my hands’ tissues man…… still feeling the heat now from the “43-48 deg C” experiments, gotta use some ice packs.
Especially my right hand, it’s still noticeably burning and not subsiding even after like 10 mins of rest.
Not joking, esp for my right hand.
I was actually under the assumption that the temperature would be dropping because the driver stepdowns from Turbo to cool the light. The direction of the temperature really depends on a lot of factors, such as ambient temp, surface area, mass, etc. So temps could be dropping, going up, or at static equilibrium. Not going to debate what temperature is manageable because everyone is different. Also some people, like myself like to leave lights tail standing to ceiling bounce while working so I wouldn’t even mind if the temps hit 60 deg C as long as I can quickly turn it off.
Btw, none of the examples I used above are fan cooled.
Put some aloe vera and ice pack on. You’ll be fine shortly
I’m ok with the ice application and 80-90% of the “heaty feeling” is gone now, the feeling on the right hand was as if the heat would not go away, though it wasn’t a high level heat. I was pushing up to 48 deg C on the right hand even though it was not > 20 secs.
Gezuz, i went to google…… not fun man.
It’s good to know. Don’t push it with regards to hand holding our powerful flashlights.
This is muscle tissue damage, not burns.
Predicted times to reach muscle necrosis over the temperature range from 37–50°C, based on data by Meshorer indicating that 30 min at 43°C is sufficient to cause damage to muscle
At 41°C, the predicted heating time is down to 1800 minutes, or 1.23 days and at 42°C the predicted time of heating to approach the threshold for damage in muscle has dropped to 230 min.
People have done that to themselves with laptop computers. Apparently, some machines can hit case temperatures of up to 50°C if cooling airflow becomes too restricted. I always used to put my laptop on a wooden chopping board when it was in my lap or on a fabric surface like my bed.
Oh yes…definitely, i have come across a colleague who nearly injured himself that way. It’s like a slow cooking kinda thingy, you would not know that you have actually injured yourself until a while later as the area becomes “hot and red”, inflammation or something.
Same thing goes for thermal baths/hot springs here in Asia, have seen signs not to take a dip should the temperature go above 42 deg C or something like that, and even at 40 deg C you should limit yourself to very short durations only. I have done 39 deg C, still pretty ok.
Water, like aluminum, is going to conduct heat extremely efficient to your skin and tissues.
Fever at 42-43 deg C is not uncommon and usually no permanent damage. I don’t see how that temp can cause skin burns.
Huh, are you very sure about the 43 deg C fever part? I have kids, one went through 40.7 at the Accident and Emergency dept, and from my research 43 deg C is not what you’d described as common.l (not uncommon)….
So you are also saying that the previous NCBI gov medical article about 43 deg c at 30 mins causing muscle tissue damage is wrong?
Edit - just a quick google, 41-43 deg c is hyperpyrexia and is very serious. In fact past 43 deg c, is usually fatal.
Anyway, The above is just for info. I guess your mileage may vary, everyone lives their lives differently….
When I was a kid I experienced several fevers that peaked into the 42 and I think once hit 43 but can’t remember for sure. Went to E Room and they gave me some fever meds and ice. I think it is not that uncommon but I might be wrong.
It is called a fever when the core temperature of the body is too high. The best way to measure (eh, estimate) this is to stick a thermometer in Uranus. Because adults are more capable to refuse such a treatment, they are often temp-ed under the tongue or in the armpit. That is even more of an estimate. Today the temperature inside the ear canal is measured with an IR thermometer.
Adults are less capable to shed heat generated inside the body than children because adults have less body surface per kg body mass. Shedding of heat can be supported by a fan, a wet sponge, wet sheets, or even a bathtub filled with ice (Haagen-Dazs?). In adults a fever of 39.4 degrees Celcius becomes dangerous. With children that is over 40 degrees Celcius (104 F). Such temperatures are not uncommon with young children, just stay alert. Though in most cases the temperature drops as fast as it goes up.