Not sure if related, but I received u3 1a when I ordered u3 2a. Does tint Mayer? Is the only way to know by measuring current draw?
If the issue with the XM-L2 U3's is a higher Vf, that's bad news for the single cell builds. I modded a cheap zoomie with a XM-L2 U3 1A on a 16mm Noctigon and the results were outstanding, but driven at only about 3.5-3.9A or so. If it has a higher Vf, then it will drop output at a faster rate than the XM-L2 U2 1A's I would think. Of course with everything else equal - LED wires, spring bypass's, etc.
Thank you Richard, but that’s hardly necessary. Pretty sure we’re all familiar with the Cree lottery by now.
My 2nd out of the 10 1A’s I bought from you is making 1480 lumens (1425 at 30s), de-domed, at a miserly 4.97A. I can live with that. 
Turbo step down has it at 2.35A for 814 lumens, can also live with that. So it’s all good. 
Edit: FTR, I just did a Vf test on this de-domed 1A on an Efest 35A and got 3.900Vf. So yeah, therein lies the problem.
I want to clarify: I know that this probably won't be an issue for the majority of those who bought these emitters. I just want to make sure that if there is an issue, we will make it right. I didn't mean to sound the general alarm!
Is it known why the Vf differs? I don’t recall hearing anything about why emitters have a different forward voltage, does anyone know why this batch of U3 1A’s and others would/could have a higher voltage requirement? What makes it so?
This 3.9Vf is among the highest I remember recording.
They’re calling for a min/max of 2.85-3.5Vf. With a typical of 3.3Vf at 3A. The curve in their charts trends towards no more than 3.4Vf up around 4A but of course that’s off the charts.
Edit: Match’s charts show 3.8Vf at 5A, not reaching 3.9Vf til 6A.
After seeing your post, I just realized my recent order of a XM-L2 U3 2A is also 1A as well. I wanted to change the LED in my TK41 with this, but I guess I’ll order another U3 2A.
1A will give you a little more of a blue/purple tint compared to 2A.
For those of you who received the 1A instead of the 2A tints, please e-mail us and we'll get it taken care of.
I just built 2 M6 Mod 2s with the new XM-L2 U3 1A LEDs. They both did over 5000 lumens on my meter at startup, which is about a 7% increase over what I normally have seen with the U2s. I have had a few before that have done 5000, just barely, but most of them are around the 4500-4600 mark.
We received the chargers this morning. There are pretty cool! We tested each one and greased all of the sliders and are in the process of packaging them and shipping right now. If you pre-ordered, your charger will go out today.
Already hard at work...
Nice, I wasn’t expecting these until the end of next week!I see you have mine ready to ship out already, thanks for the great service!
I will keep an eye out on your other ‘limited builds thread’ for these beasts to go on sale 8)
What? This is just the good old Supfire M6 Mod 2 just with the U3 instead of U2. Not really a new light.
That U3 seems to be definitely cool output, right? My Cree XM-L2 PDF does not list it and it was a recent download.
You should be able to get U3 emitters in 1A on down to whatever, 2C, 4C, 3D…not sure what they’re going to release in that one. But it’s the 1A that makes it cool in color output.
A U3 in 3D would still be a neutral white with that hint of rose.
The breakdown on power binning…
I have had several people ask me why I am no longer carrying the LUC V4 chargers. I have had a higher than average amount of failures with these, with almost all failures occurring within the first week of ordering. Whenever this happened, I would lose money because I would have to pay to have the charger shipped back, then Efest would make me pay for the shipping cost to receive a replacement under warranty. By this time I was already under water on that charger, but I kept buying them because when you got a good one they were still a nice charger for the price, and they were in high demand.
The last batch of them had about a 30% failure rate--higher than any other batch, and completely unacceptable. At least one of the units popped loudly while the customer was nearby--hard enough that it cracked the screen from the inside. In the past, Efest wanted me to just send them a video of the charger, showing that it didn't work and stating identifying details so that they could know it was from me and what the date was. This was fair and is fairly common practice in the industry. So, instead of wasting time and money having them send the charger back, I had several customers take and send me a video to their specifications which I then forwarded on to Efest with a description of each requesting a warranty replacement. Efest refused to accept the videos and denied my warranty claims. I refuse to continue to support this kind of behavior and I will not continue losing money selling their chargers without support. For these reasons, I will not be carrying any more Efest chargers.
That is unacceptable. Makes me lose interest in sending any more money Efest’s way.
wow… what horrible customer service….
I used to recommend this charger to others as a 4x1A charger (usually recommending against a Nitecore i4). So what is the best bang for the buck reliable charger that does 4 cells at 1A each? Is it the SoShine SC-S1 Max? (Note: I may be wrong on that model name; it's the "good one" HKJ reviewed.)
-Garry
Wow! Mixed feelings on that one as I have more than one of those LUC V4 chargers and yes, they are a problem. The one that I have that is still working (the other 2 are down due to my own stupidity, which, come to think on it, is due to the fact that those 2 came to me with Euro plugs… and the fact that I had re-assembled my 12VDC light with a car charger socket bassackwards! Incan bulb worked fine, 12VDC charging port, not so much!!!) cuts off the charge at 4.18V. This is not entirely bad, but for testing newly built lights it doesn’t give full power to the build.
I LOVE the Efest Purple cells, be they 18650 35A’s or 18350 10A’s and for me, there simply isn’t a better cell in the class when it comes to their IMR10440. I get 3.4A from the tiny AAA sized cell in my Texas Poker!
So, with their cells being at the top of their respective classes I can’t dismiss Efest altogether. But my XTAR chargers are working far better and the LUC V4 stays in it’s box.
Can’t blame you at all for this decision, and I’m sorry for any influence I may have had in your decision to carry those in the first place. It’s been an ugly venture from the start. 
Garry, the XTAR XP4 works better for me than my SoShine unit. My SoShine developed an issue with Bay 2 not charging properly so now I very rarely use the charger and then only bays 1,3, and 4. Bay 2 would charge slowly, topping off at around 4.15 instead of 4.20V. Don’t know what happened, I used to use it as my go-to charger. Also on the SoShine unit, if the cells were quite low when put in the charger then the charger would heat up more at Bay 1 and get that cell pretty warm during the course of the charge cycle. I added vent holes and learned to use a fan when charging depleted cells with the SoShine Max.
Now I have 2 XTAR VP4 units, an SP2 and an VP2. The VP2 allows charging 26650’s.
I can still use my LUC V4 for 2A charging to a pair 26650’s to get them near full charge, then switch them to the other chargers to finish, when necessary.
Edit: Ooops! I stated I have 2 “VP4” when they’re XP4, sorry bout that!