Following DIY Perks's video about 1500w COB, I realized that one of my suppliers are making these at much lower price with roughly the same spec:
Size: 88mm OD/ 72mm LES
Voltage: 35-38V
Current: 7-9A per section (6 sections, for a total current of 42A-54A)
Wattage: 1500w-2000w (250w-330w per section)
Color Rendering: 95 Min. CRI, 3-Step McAdam (<3 SDCM)
Efficiency: 100lm/w (listed as 100-140lm/w but that also includes 80CRI and 90CRI variants, so be safe to assume that 95CRI will be at the lowest end)
Light output: up to 200000lm
CCT: Can be customized, but I would go with 5500k and 3500k.
If you are interested, I expect I can sell these emitters at ~$190 each after shipping cost and import taxes on my end.
The caveat here is that, this beast of an LED with driver can draw up to 12A on 220V mains or up to 20A on 110V. That could cause the circuit breaker in your house to trip. Also, thermal management and power delivery on its own will be a challenge and might add up to the overall cost.
Now turn this one into a beyond 1 million lumens high CRI flashlight! :-D Would probably need some big automotive heat exchanger or car radiator. Plus some nearby mains plugs or a mega-battery. O:)
1 million lumens would need 5 of these 2000w monster powered on simultaneously, which would require over 10kw of power for the rig. That would require 50A of 220V mains or 100A of 115V mains.
In my country, the legal limit of the receptacle amperage is 16 Amps. The power grid connected to my house is only capable of handling 15 Amps. Only one of these monsters would already be cutting it close to the power grid’s limits.
So this much power for 1 million lumens will definitely be a fire hazard (in many ways) and possibly illegal in my country.
The setup in that video was a “mere” 100k lumens. Which could be dwarfed by just one of these emitters.
IMHO no practical use for it except maybe some street lights or something like that.
In practice if you need that many lumens better to use multiple COBs. Price will be similar or less per hi CRI lumen, much easier to cool and better distribution.
That being said, I can see someone to build portable light with that thing and LiPo pack (easy for them to give 2000+W, like this one on the cheap side Tattu Plus 1.0 44.4V 16000mAh 15C Smart Battery Pack with AS150U Plug).
Driver may be a challenge but there is a lot of these DC/DC converters with constant current/voltage output. Seen some 1800W
So, who is building it
1500w from a single light would make sharp shadows. And $190 isn’t hobby level at all. It might be useful as a street light for a city, but that’s all I can think of.
I had to say but, in the following video from Matt Smith (vestureofblood), it becomes clear that the cheap 100W COBs the above guy uses in his watercooled flashlight “ain't that bright”:
In theory the video should start at 4:56.
It can be seen how those emitters are already a bit strained at 6K @#$% CRI lumens.
So that 72000 lumen flashlight is probably more like 48K lumens. O:)
As a 100w COB LED connoisseur myself, I think I have learned a lot of ins and out of these emitters. (Warning, rambling ahead.)
There are several grades of these COBs, most notably the size of the individual dies that makes the entire COB. In the old-style COBs found on eBay, each die will take 1w of load, so 100w COB will have 100 of these.
The “best” one with biggest die size I’ve seen and bought are using bridgelux-made 45*45mil dies (or “chips”). These are rated by the manufacturer as having 120-130lm/w (@70CRI) efficiency. These are expensive and will cost you $10-$20 from eBay.
Then you have the lesser grades using 38*38mil, 35*35mil, 33*33mil and 30*30mil. These are rated at about 100-120lm/w and will cost roughly $6-$9 from eBay. Then there are the cheapest one that uses 24*40mil or smaller/crappier dies. These are the $2-$3 ones you usually encounter on eBay and these will only be rated at 75-90lm/w.
That assumes all the dies are not defective, especially the cheaper parts where the defects are common (the “checkerboard pattern syndrome” at low power as demonstrated by BigClive). This will further worsen the efficiency and shorten the lifetime of the emitter as a whole.
I wish eggs had that ratio of Albumen to Yolk……(Love me some swollen ovum) 
