+1, the tk75 makes an awesome host/light imo, for its size it still holds its own today .
Agree.
Xe-Vision 70W model (regulated HID with very pronounced cooling fins). It produces 7500 (bulb) lumens (with 1-4Mcd) and never dims.
But it’s very expensive for non-professionals.
Haha, that’s a great joke 
Thanks, I’m glad at least a few people here have taken physics classes in school xD
No joke
The TN42 is highly regarded, not cheap
Heck we all gave our admin SB a flipping Meteor, not cheap.
Special lights like titanium Reylights have their place, not cheap
People mod lights with parts costing more then the host.
Maxtoch is highly regarded and bought, not cheap
Come on Big E, you are nice, you mean well, surely you can say things in such a way the message comes across , just bear with people like me not at your level and it can be so good. Friendly and explaining things are key, you do the second thing but just read and add a few “IMHO”s and smileys so it reads nicer, you can do it and it would help your great input to be understood better 
I’m going to stop derailing the thread now, but the last thing I’ll say is go to google and look up all the posts criticizing expensive flashlights and exotics using “site:budgetlightforum.com”. You’ve been here longer than I have, so you should have seen more than I have.
Olight X9 Marauder. 25,000lm with fan
True that.
I was thinking of that one, but I never actually saw it in pictures or videos!
It definitely seems like the winner although I’m not sure how long it can sustain 25k lumens even with a fan.
It seems like it steps down after 5 mins, then stays at 6k for 80 mins: 
EDIT- this forum keeps breaking up my links 
Maybe this one will work? Redirecting...
The original question by the OP was, “what light can maintain 3500lm for 30 minutes”. Pretty sure this one could.
I usually forget something, this time I forgot to pull the cells from my TR-J20 and see where they stood before testing. I know they’ve been sitting here for a few months at least, used the light a few times but not much.
Level 4 showed me 4574 lumens when I first checked it out, level 6 of 6 was doing 11,902.5, so the cells must have been down to around 4V as this usually does around 14,400 or so.
At the start of timing 4347 lumens
every 5 minutes thereafter, to the 30 minute mark…
Start……4347
5 min……4140
10 min…4140
15 min…4071
20 min…3933
25 min…3691.5
30 min…3346.5
The fins of the head were hot most of that run, but not too hot to hold. Almost though! I know this light tends to heat up the bezel and very top end, without putting much heat down into those deep fins. With the heat sink in it all the fins were hot. The battery tube was warm at the head end but easy to hold, even with a finger up against the head. Ambient temp is 79º F, slight air circulation in the house from ceiling fans and AC unit.
The 3 32650’s came out of the light after 30 minutes at 3.75V, 3.72V and 3.69V.
He said “So if we wanted a flashlight capable of running with say 3500lm, for 30 minutes.” notice the “if”, he was just giving an example while talking about turbo vs second highest level for a hypothetical flashlight.
The actual question is in the topic title.
“Which flashlight can run the most sustained lumens?”
And I gave several examples that do about 4-10k lumens continuously.
I hear you and NO, that IS NOT what I want anyway….
Thank you, I did take a couple of Physics classes way back when. But, in reality; the second one took me. :person_facepalming:
But I do hear & understand what you are saying. :+1: Most of it anyway……
Lead is bad, copper, aluminum, and even tin are more conductive.
This is why lead free solder (made of tin) is more conductive (for heat) especially if it has added silver content.
Copper and aluminum are far above these though, by many times, so I don’t recommend making a heatsink out of lead or tin, it’s just useful for joining two surfaces together by soldering.
Fun fact: liquid metal thermal pastes can be just as heat conductive as solder
This is why you see me trashing / not buying any of the modern step-down lights. We have dropped the bar in the name of big lumens. It used to be that a high-lumen light could run at top level for the full runtime—not anymore. I love Acebeams just because they don’t wuss out by having quick step-downs on their big boy lights. I won’t own a light that steps down. And the ones that step down gradually play games with my head. I feel like I’m being manipulated. These really annoy me. We need to demand that manufacturers include appropriate heatsinking in the building and not give 9,000 lumens, followed by 1,200. It’s an insult. Even the new Fenix 26650 XHP70 can only hit turbo for 5 second—seriously, five F’ing seconds! And yet they had the gaul to advertise it:
I’ve lost all respect for manufacturers who drop the bar like this. But it’s our fault—we should never have allowed it.
Agree.
But this problem mainly caused by community and testers. Lets start new age - make main tests with lumen and throw after 10min ambient.
4 bare emitters with quad optics are always better than one 4-die emitter. Better heat spreading, better beam shape, same throw in same diameter with less optics height.
5 seconds…… :person_facepalming: . That is beyond sad, it is pathetic!!
Excellent idea…… :+1:
………
Well said by both of you guys…… I never really gave it any serious thought although I though it was crappy. You guys have enlightened me as well as hit the nail right on the head.
I usually just don’t buy a light that does that. But from here on out I’ll be vocal as to why I would not buy it. Hitting them in the pocket book & on the bottom line is the only way they will probably change things. :+1:
MagLite built a light that could last all night and take a beating, it was revolutionary. Now everyone trashes MagLite for not coming into the new age. Go figure.