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Xtar’s D28 3600 light looks great: powered by four 18650s, larger reflector to gain maximum throwing distance with 8-degree beam and XHP70.2 LED at 7000k, and turning/locking/illuminated magnetic switch showing approximate battery time remaining using red and flashing red at appropriate battery interval times left.
Published “parameters” also look great: 3600 lumens at 2.5 hours runtime, 2000 lumens at 4.0 hours runtime, etc., with a stunning 550 meter beam-throw at 8 degrees (see attachment). Why not just carry one (along with two additional backup lights) for a shorter cave/rn dive? Xtar makes only a lantern handle, but with the bolt hole cut in the light, I’m sure a 3D printer can do the job to fashion a Goodman handle if nothing off the shelf works. With these specs and for shorter dives, why not “cut the cord?” After all, I don’t think even my perfect eyes would be able to tell the difference between Bobby’s 4000 lumens at 6 degrees and Xtar’s 3600 lumens at 8 degrees, would they? (As an aside, I intend to buy Bobby’s light in the future regardless of the outcome of this discussion and inserted the question only to stimulate discussion on the topic so I can understand. His light is in a whole different league and is absolutely gorgeous.) However, my educated guess/fear is that the Xtar's 3600 lumens would shine for about 37 seconds or the like before drastically diminishing, notwithstanding the water cooling factor, to a much lower lumen level and then tapering out similarly to many cheap lights.
I just can't find any independent stats or tests. Many Chinese flashlight manufacturers fabricate wild numbers without substantiation; Xtar may be quite different because it keeps an open ear to this board and promotes on it, and as such, one would reasonably expect that it wants to maintain legitimacy. Yet, at 1lumen.com, results are shocking when reviewing data from power drain charts for other manufacturers who clearly inflate numbers beyond a small margin of what an acceptable "white lie" would be to a reasonable person.
Accordingly, based on the above, and related only to carrying the Xtar D28 3600 for shorter cave/rn dives, i.e., 45 minutes to two hours, I ask the following:
Published “parameters” also look great: 3600 lumens at 2.5 hours runtime, 2000 lumens at 4.0 hours runtime, etc., with a stunning 550 meter beam-throw at 8 degrees (see attachment). Why not just carry one (along with two additional backup lights) for a shorter cave/rn dive? Xtar makes only a lantern handle, but with the bolt hole cut in the light, I’m sure a 3D printer can do the job to fashion a Goodman handle if nothing off the shelf works. With these specs and for shorter dives, why not “cut the cord?” After all, I don’t think even my perfect eyes would be able to tell the difference between Bobby’s 4000 lumens at 6 degrees and Xtar’s 3600 lumens at 8 degrees, would they? (As an aside, I intend to buy Bobby’s light in the future regardless of the outcome of this discussion and inserted the question only to stimulate discussion on the topic so I can understand. His light is in a whole different league and is absolutely gorgeous.) However, my educated guess/fear is that the Xtar's 3600 lumens would shine for about 37 seconds or the like before drastically diminishing, notwithstanding the water cooling factor, to a much lower lumen level and then tapering out similarly to many cheap lights.
I just can't find any independent stats or tests. Many Chinese flashlight manufacturers fabricate wild numbers without substantiation; Xtar may be quite different because it keeps an open ear to this board and promotes on it, and as such, one would reasonably expect that it wants to maintain legitimacy. Yet, at 1lumen.com, results are shocking when reviewing data from power drain charts for other manufacturers who clearly inflate numbers beyond a small margin of what an acceptable "white lie" would be to a reasonable person.
Accordingly, based on the above, and related only to carrying the Xtar D28 3600 for shorter cave/rn dives, i.e., 45 minutes to two hours, I ask the following:
- Is there any known, independent validation of Xtar's published “parameters” of 3600 lumen for 2.5 hours and 2000 lumens for 4.0 hours? If not, can an engineering type reading this drum up some numbers that correlate to battery power (18650 x 4), lumens, and likely run time? The bulb is the XHP70.2 P4 and I don’t know what P4 stands for after it.
- Has anyone used this Xtar light or know of anyone who has used it? Please focus discussion on only this light and not other Xtar lights.
