Well, technically, the XHP-35 won’t do 1000 lumens at 2.3A current draw either. As the cell dies the current will go up, increasingly more until the cell is stomped on. So in the end it’ll balance out something like a normal emitter with higher current draw. I don’t know exactly how it’ll pan out, probably some here that can figure that.
I personally would rather see the new XP-L W2 2B doing 2000 lumens in this light, pulling some 6.7A, with a tighter hot spot. That’s just me though.
Actually w2 bin is very close and xp-l2 can reach 1000 with less watts
A beginners question. What does the pcb board in the tailcap the spring is on do?
thanks for the comparision, the uto2 is surely the way to go if you ask me. i would have one already if it wasnt because of the ui. can’t remember off the top of my head, but it probably has to do with holding the switch to turn on or off light……i hate that.
are you planning to mod the light in any way? i know the lux can be greatly improved with an xpg2.
vinh actually sells his model of the manker 21, i think with his driver and xpg2, it more than doubled stock.
with still 1000 lumens.
Would a flat top 26650 protected Keeppower cell work in the UT02 and give max rated lumens?
I wish it would of have a tactical switch in the bottom , and the one in the head forma changing mods;
You answered your own question, least 50%. Only purpose of the PCB is to mount the spring to it, and give a point of contact to the body tube to complete the ground circuit. When the tail is tightened, the top edge of the tube makes contact to the ground ring on the PCB. This is why it does tail lockout so well - with quality anodized threads, slightly loosening the tail breaks electrically contact at that point of the outer ring on the PCB.
+1
The XHP35 and boost driver introduce all sorts of losses in a single cell light.
If someone does XPL W2 with shaved domo in this form factor of light I will buy it
Putting the 12V XHP-35 into a single cell smallish light with a large enough reflector for good throw was obviously a design goal. You can’t count losses when the goal is achieved. If the goal had been maximum lumens, or maximum lux, or minimum voltage, well you get the drift. They wanted the light to have this new popular emitter and they made it happen. That’s success.
Somewhat similar to how Chevrolet sells thousands upon thousands of Camaro’s that DON’T have the high performance engine. All those people driving a 6 cyl Mustang, an underpowered Camaro or even Corvette, they got what they wanted at the price level they were willing to pay, that’s not losses that’s a win win.
The complaining is usually because an individual wanted a different parameter considered for the design, like a multi-tool that never has the right combination of components. But it’s an impossible task. The manufacturer would have to offer up a special order with ten’s of thousands of options available to be able to please everyone, then assemble the product to the desire of the customer…and even then some would have issue. And the price would soar, so more would have issue.
I think Manker did a nice job on this U21. I think the Utorch UT02 is also a very nice light. When you look at what they do, how they’re made, the fit in hand and overall performance (including the charging performance) they’re a win at the price point. Remember that the base price has a narrower margin of difference, base price is $50 vs $65, between the two. The gap comes in with Manker’s refusal to do a group buy for us here at BLF.
FWIW, Vinh’s driver is Richards driver. 
In other words, Vinh mods a light in much the same way as you and I. He’s OCD about the emitter choice, he’s willing to buy a lot of emitters and cherry pick what he wishes to use, other than that and his attention to detail in focusing, he’s just like the rest of us. The high prices come with all the non-cherry emitters and time spent. Trust me, if you put in the effort and time on a build like Vinh does, you too would charge the premium.
Lexel, I recommend that you purchase the Utorch UT02 in this group buy. Play with it, get a feel for it, and if it doesn’t satisfy your needs then do what BLF is known for… modify it. 
The car analogy is interesting, but in this case wouldn’t it ba a Camaro with a bigger engine that has less performance, that has lower milage when driven the same way and that costs more and is probably also less reliable, than the other one that could exist (the XPL one or smaller better performing and more frugal and reliable engine if you will).
That would be how YOU would justify buying the RR version.
Meeting the design parameters is about giving people what they want. The XHP-35 is popular these days. Lights with a single cell boosted to the higher voltage emitters are selling well. So design teams pay attention. What’s selling? That’s what you’re building. If that means a bigger engine with lower performance, lower mileage and higher costs, paint it the most popular color and sell away!
Remember, China is a very big place. They sell a vast majority of the lights they produce to a general public that are not flashaholics. Appeal to your majority customer, just good business sense.
The question is do people buy a particular LED, or performance specs, lumens , throw, runtime etc…in other words, would this flashlight sell even better with better specs and an XPL, who knows ?
I suppose you would have to be pretty well versed in flashlights to recognize what a XHP35 is , but then again chances are if you know what it is you are also aware a XPL would fare better in all aspect in a single cell light.
Not so. The very newest and brightest XP-L W2 2B only makes 955 lumens at 3.15A in a flashlight like the Convoy M1, modded to the Nth degree. So for this light to be making 1094 lumens on 2.3A tail draw right out of the box is really a nice feature. Obtaining over 600M in throw at this relatively puny current draw is also a great feature, besting the Nightcore P30 at it’s own targeted game, throw. Again, an XP-L HI used in a 3A light to make a goal in throw and selling for well over the price of this light.
And giving the ability to use a 5200mAh cell, as compared to the relatively puny 3500mAh 18650.
So sometimes it’s a matter of options, design styles and variance, as there is no given best in anything… appeal to the public with money in their hands.
From the manufacturer’s perspective, how do you design a flashlight with enough appeal to pay for it’s design costs? How many have already been done? How do you create a new market? You use the newest, you pay attention to what’s drawing rave reviews, you make people want what you have by doing something that hasn’t been done. Marketing.
Perhaps now that they have people’s attention they will offer some emitter choices… who knows?
Yes. Utorch acomplished their goal. Every manufacturer plays on people’s perseption. The things that sell are the things that are perceived as the greatest and latest. However, what is perceived as bigger and better and brighter is not always reality. And this is why we critique(not complain). Let people that are not flashaholics buy what they perceive as best while we stay educated in our pursuit of the actual best performing lights in practice.
My critique of the ut02 is similar to my critique of the blf d80. When specifications are given I expect them to be reached within reason. When they are not, I feel cheated. I expect to be cheated on specs from eBay and almost any other place. But when I come to blf I expect better. Many first find their way to blf because of all the junk that is out their. And many of us were scammed by exaggerated claims in the beginning. It’s hard to know who to trust and so we find solitude here believing we will be given accurate information as a guide to our purchases. So it’s not about “stop complaining, it’s a great performing light for its size” and more about feeling a bit of that former mistrust creeping in when a promoted light doesn’t meet the specifications that were promoted. Specifications play a major role when choosing a light so they should be held to a standard, at least here on blf.
So, I critiqued the blf 80 pointing out under performing specs, yet it is one of my favorite lights. I have 20 of them sitting here right now and am making lights for my whole family. I think it is also ok to reveal the subpar performance of the ut02 even though it is still a great light as you suggests. I think it will become the next d80 for me. It IS a great light!
This is very puzzling as on the paper the XPL W2 is more efficient than the very best XHP35 HI bin (E4) , and this without even taking into account the less efficient boost driver.
Interesting “perception”. BLF has nothing at all to do with the claims of a Chinese manufacturer. BLF members have nothing to do with those claims either. We learned a long time ago that most manufacturer’s use the datasheet in their lumens estimations, not actual light output. There are a few of the big guys going to ANSI ratings, but you’ll pay for that apparently as those are usually more expensive lights. Budgets are met by cutting corners. Big green sphere’s that give the ANSI ratings are not cheap.
The D80 was thoroughly tested, even by myself as I was on the team, and then they changed specs. That’s outside of our control. A disappointment for all. And that was Lucky Sun, not Manker. A different basket of fruit, if you will. Manker was guided in the building of the X6/X5 lights and the Bistro drivers. I myself sent them a component list to build the drivers by, as I’d been building the drivers successfully for most of a year at that point. They did not adhere to the list, the drivers act up under heavy load.
BLF cannot be held accountable for any of that, if you think you’re coming here to get the true story, you’re being misled somewhere. Manufacturer’s are out to make money. The good people of this forum are picking up the pieces and running with em. Group buys are held and it’s largely a trust issue that they sample light will be a representation of the production light. We as members usually try our best to ensure the group buy is a face value thing, but we don’t have any control over it on the other end.
I can test a light, I can give you the actual numbers I see as recorded with my cells, chargers, and testing equipment. I cannot say you’ll have the same result with the light you buy. I have no idea if they pulled a sample light off the shelf at random and sent it to me, or if they cherry picked one they wanted me to review… I just don’t have any control over that whatsoever. The one thing you know here, in my thread, is that it got called like I saw it. I won’t pad anything or cheat to either direction, not for Manker or Utorch or Fenix or Nightcore or any of em. I’m not getting paid, I’m not getting swayed. These 2 lights are a good example of this. I will be sending the Manker U21 to a forum member in Malaysia to further test and prove out. Because he asked. I will be tearing the Utorch UT02 completely apart, torturing it, perhaps damaging it, perhaps modifying it. If I kill it, I’ll rebuild it, doesn’t matter to me either way. A lot of the lights I’ve reviewed have been given away. Some have been used in GAW here, one or two has been heavily modified and sold at the cost of the mod components. That’s just how I do it.
As with all things, weigh what you see, measure what you read, make an educated decision as to what’s going to work best for your needs. Then go with it. And have a Merry Christmas in the process. 
James, it’s staring you in the face.
The new XP-L W2 is a domed emitter. HI domeless causes losses, not as much so as full out de-doming, but the power drops (hence V2 being the highest vs V6 with a dome on, previously) and the tint suffers as well. Look at the XHP-35 HD for your comparisons.
I’ll dig out the notes on my C8 with W2 2B, the one that’s making 2024 lumens at 6.67A, I’ll see what the comparative amperage is doing in that light with it’s big copper pill under the emitter.
Edit: In the larger C8, smooth reflector, maxed out mod I test level 6 of 7 at 3.34A on a Samsung 30Q, this yields 1045.35 lumens.
I’m very gratefull for the testing you do and trust your total honesty, i also trust Cree’s data sheet, they are rock solid and honest, and above all they eliminate the myriads of external factors (ie who knows if the chinese seller is really selling W2 bin XPL, or the reflow is good, if the homemeade “integrating” aparatus scales well, if the luxmeter is well calibrated, if the cell is the same voltage, if the flashlight has the same resistance path etc…)