Re: Wave of Ti Haiku XP-G flashlights
Hi guys,
It's about these warm XPG Light Engines. Where to start?
1) Personally, I don't care for the warm tint myself and prefer neutral to cool tints. But that is strictly a personal preference and I do respect others who have different preferences.
2) There seems to be some false perceptions that warmer tints equate to better color rendition as in higher CRI.
3) From the very beginning with the Luxeon LED's there has been emphasis placed on tints of the LED's which initially were all over the place and IMHO, much more justified then than today with the latest generations of LED's. Although recognizable when viewing the beam itself on say a white wall, these tints are not noticeable or significant, IMHO, when one is viewing an object or field of view being illuminated by the LED.
4) I have avoided playing the tint game for a number of years now and attempted to get the best LED's I can to build with based on their efficiencies and flux and in terms of tint, attempted to get a reasonably neutral or white LED but often on the cool side as these typically are higher in flux.
5) If the priority in a light is based on the quality of light then my choice has been for a LED with a high CRI and to date I have found the High CRI LED's from Nichia to be unequaled in these regards. The price paid is a loss in flux (lumens)
6) With repeated demand and requests for a "warm" offering, I went against my personal wishes and did purchase an order of warm XPG LED's which I have been building with and slowly these LED's have been used up.
7) I discovered in the process that these warm XPG's in addition to being lower in flux than their cooler counterparts also have a higher Vf. This has resulted in some issues for some of you who use primary CR123 cells and find that it can become difficult to shift out of high level. (more on that in a moment)
8) At one point I was down to just a hand full of these LED's and they were not mounted on MCPCB's. I usually set up and mount a group of 36 LED's at a time for sake of efficiency but I didn't have that many and I am also getting low on the XPG MCPCB's. Requests have been sporadic on the warm XPG's, at best, and I was planning on letting the warm Haiku XPG program die on its own accord. But then there was a bit of a revival in demand probably due to some posts here on the forum by those of you who like this light.
🙂 I hadn't posted here that these were no longer available so I ended up doing a short mount on the balance of LED's on hand. I am now down to three of these warm XPG's left and when they are gone it's over. Sorry.
9) In the absence of offering a warm Haiku XPG when the last of these LED's are used up, in my defense I would point out that I am still offering the Haiku in three versions: The Haiku High CRI (where quality of light, lack of tint variation and maximum color rendering is of most importance). The Haiku XPG (where maximum throw and general all around lighting is the goal). The Haiku XM-L (Where maximum flux [lumens] is desired in a concentrated ram of flood is the goal and beam pattern at all three levels is most optimized in transition from spot to spill)
Back to the issue mentioned in #7 and to be considered by anyone wishing to purchase one of the three remaining warm XPG's or anyone planning on picking up one of these warm Haiku XPG's on the aftermarket from another member. The 3S converter I use has a weakness in its design where as a battery gets depleted it can become more and more difficult to shift out of the high level. This appears to be a function of the voltage provided the converter, while under load. If the Vf of the LED is high which seems to be typical in these warm XPG's then this issue will come up sooner compared to the "stock" XPG's I use. Some if not many of you have avoided this issue from what I gather by using R123 cells which have a higher voltage than primaries and this seems to solve the shifting problem. As a builder, I can avoid this issue from coming up in one of two ways. One is to not use the LED and the other is to reduce the high current level setting on the converter. The first option is the one I will ultimately take. The second option is one I want anyone considering a warm Haiku XPG to consider unless they plan to use R123 cells.
To cloud the situation a bit further I should point out that although these LED's typically have a higher Vf that is not always the case. For those of you familiar with Cree and their binning, you know that you can purchase LED's based on color/tint bins as well as flux but the LED's are not binned based on Vf and any reel of Cree LED's will have individuals that vary in Vf. When I was fine tuning the Haiku XPG I chose a high drive current that was reasonable as based on the LED's I was using, the thermal aspects of the Haiku light and the ability of the converter to perform. As it turned out when I added the option of warm XPG to the mix there was an occasional issue with some of them. (but not all)
To a great extent, the Haiku XM-L seems to have replaced the Haiku XP-G in interest and demand and I think this is for good reason. The XM-L is a fantastic LED and its boost in efficacy and flux for the most part, IMHO, compensates for its larger die size, relative to the XP-G. There have been some requests in inquires about a warm XM-L offering and guys, I am just not going to go there. I can't satisfy everybody no matter what I do but I certainly could loose the balance of my hair and my sanity if I tried to. :duck:
Here we go...
