DGX PUSH Handheld Light Kit - Spot Beam

[stuartv]

Kryssa's post is from last April. She's probably squared away on lights by now.

For posterity, at the time of the OP I only really knew of one common LED emitter that was being used in all the "good" cordless lights. The Cree XM-L2. It comes in different binnings (i.e. quality levels, if you will) but they are all in the rough vicinity of 1050 lumens, max output rating.

To me, that is too bright for ideal night diving use. So, I would want a light that bright to have an option for lower brightness levels (which the DGX does not have).

The latest news, though, is that Cree came out with a newer LED emitter that is significantly better than the XM-L2 (IMO, for dive light usage). It is the Cree XHP35. It is rated for about 1600 lumens. And, it is physically smaller than the XM-L2. 3.5mm vs 5mm. That means that it is a lot brighter and it is easier for a manufacturer to get a tighter beam out of the light.

There is one new light out that uses this new LED (that I know of - there could be more): The Xtar D26 1600. I have one and it is significantly brighter than the lights I have with an XM-L2 LED in them (which includes the DGX 600). And it has a tighter beam than any of those, also. Unfortunately, the first production run of the 1600 has a couple of electronics issues that make it not really acceptable for use in almost any capacity. BUT, the good news is that Xtar is aware of the issues and has supposedly fixed them in their subsequent production. I have a new one on the way and I am keeping my fingers crossed that it has the problems resolved.

So, to anyone looking at this thread, if you are looking for a good cordless light for night diving, day diving, or any other diving that doesn't require a canister light, stay tuned. If the D26 1600 is fixed, I think it will be the best light, by far, of all the lights mentioned in this thread so far. Really, it could be the best <$300 light on the market and it is less than $100. Maybe the best overall cordless light you can buy, save possibly for some REALLY expensive lights like the Dive Rite HP50 and the Halycon Focus 2.0 (or whatever their cordless version of that is called). Both of which are over $900, I think.

 

[Rred]

Stuart-
Sorry, I missed April. Scubaboard served me up the thread as "new posts".
When you mention only one emitter, or now perhaps two, be aware that "the same" emitter can be very different in different lights.

"Binning" of white LEDs (which have the greatest manufacturing variations) typically will split them into three brightness groups, and each of those into three color groups. If the "middle" bin has emitters that give out 1000 lumens, the lower bin may only produce 500 lumens and the upper bin 2000 lumens. Yes, the differences can be that great--you'd have to check the details for a particular LED from a particular maker to find out specifics.

But it doesn't stop there, either. Someone at CREE mentioned that very curiously, there are more "genuine CREE" LEDs on the market than CREE produces at all their plants. (Like Jamaica Blue Mountain Coffee, where 30 years ago only about 5000 pounds were available to import to the US east coast, but over 50,000 pounds were sold in that market.)

And ignoring the binning and counterfeits, the brightness of the LED can be very different just depending on what power is applied to it. If the builder supplies excess current, beyond the nominal rating, they can easily bump the light output by 5x or more than what is nominal. Of course, that will also cut the lifetime of the emitter by a huge factor. So instead of 50,000 hours of normal rated life (to the point where it dims to 70% of original output, the industry standard) some companies only claim 10,000-20,000 hours. Still way longer than the old krypton bulbs, sure, but still, it means they are pushing the envelope.

Bottom line, if you don't know the maker and their reputation, or they don't know their supplier? "Same same" ain't all the same, they can be very different. The variations about beamspread and lumens versus any other measurements all make it REALLY hard to compare any of them, except to say "This manufacturer has had a great reputation for 20 years and offers a lifetime warranty!" versus "Hey, this is cheap enough."

 

[stuartv]

Stuart-
Sorry, I missed April. Scubaboard served me up the thread as "new posts".
When you mention only one emitter, or now perhaps two, be aware that "the same" emitter can be very different in different lights.

"Binning" of white LEDs (which have the greatest manufacturing variations) typically will split them into three brightness groups, and each of those into three color groups. If the "middle" bin has emitters that give out 1000 lumens, the lower bin may only produce 500 lumens and the upper bin 2000 lumens. Yes, the differences can be that great--you'd have to check the details for a particular LED from a particular maker to find out specifics.

But it doesn't stop there, either. Someone at CREE mentioned that very curiously, there are more "genuine CREE" LEDs on the market than CREE produces at all their plants. (Like Jamaica Blue Mountain Coffee, where 30 years ago only about 5000 pounds were available to import to the US east coast, but over 50,000 pounds were sold in that market.)

And ignoring the binning and counterfeits, the brightness of the LED can be very different just depending on what power is applied to it. If the builder supplies excess current, beyond the nominal rating, they can easily bump the light output by 5x or more than what is nominal. Of course, that will also cut the lifetime of the emitter by a huge factor. So instead of 50,000 hours of normal rated life (to the point where it dims to 70% of original output, the industry standard) some companies only claim 10,000-20,000 hours. Still way longer than the old krypton bulbs, sure, but still, it means they are pushing the envelope.

Bottom line, if you don't know the maker and their reputation, or they don't know their supplier? "Same same" ain't all the same, they can be very different. The variations about beamspread and lumens versus any other measurements all make it REALLY hard to compare any of them, except to say "This manufacturer has had a great reputation for 20 years and offers a lifetime warranty!" versus "Hey, this is cheap enough."

Understood.

Looking at the various binnings of the XM-L2, up to U4, they all are in that 1000-1100 range, I believe. And my earlier comment was specifically about the XM-L2 and the many dive lights that use that particular emitter (in one binning or another).

As for counterfeits and all that, i have heard it happens a lot. But, to me, that comes down to trusting the supplier of the light that claims it has Cree Inside.

Regardless, all these cordless XM-L2 lights seem to use the same batteries (either 18650 or 26650), so they all have somewhere in the same ballpark of power applied, as they all also aim for roughly similar total burntimes. So, it seems like they all have roughly similar ballparks for total lumen output. I have certainly not heard of or seen any light claiming an XM-L2 emitter that was significantly brighter than any of the others. Though I do kind of think Turbo mode on the D26 Whale is a bit brighter than the DGX 600, but I digress.

OTOH, the D26 1600 is quite visibly brighter than the XM-L2 lights I have compared it to. I have posted pictures and at least one other SB'er has also posted comparison pictures, I think. I attribute that to having the XHP35 emitter and otherwise roughly the same ballpark for power applied and optics.

 

[Rred]

It is kinda like shopping for a mattress. You know, no one really ever looks inside, and every store has a "custom" line where the only real difference is the color of the fabric, but who can tell?

In theory, if the nominal voltage for the emitter is matched to the nominal voltage of the battery(s), no current control is needed and the brightness is equal. But since lithium cells can exceed LED ratings there "should" be a controller chip in them and then there's a question of who is using what chip, what current limit, even if the LED and battery are identical. Some makers are up-front about over powering the LED, using a thermal sensor and thermal limiting to get better brightness without burning it up right away.

And of course if you put all your light output into a 20 degree cone and I put mine into 16 degrees...mine's going to look "brighter". That's a point commonly argued in dive light reviews.

Dunno. But having folks who have bought and compared several (like you) posting their comments online, is probably more valuable than running all the numbers. At least things are better than the old "change batteries every 3 dives, change bulbs every 4 dives" from the old tractor headlight Ikelite days.(G)