Kudos to Fenix on the L0D Q4 holiday special edition light

[Luminescent]

Fenix just introduced a nice L0D Q4 Holiday Special Edition light for the holiday season.


This light offers performance matching what a Rebel 100 based light could be expected to offer, and Fenix was nice enough to offer it at the standard L0D pricing with a nice presentation box.

I'm not sure that everyone appreciates the festive RED holiday color that Fenix chose for this light, but I like it, so I went ahead and ordered one.

Got my light yesterday, and, in a word, it's INCREDIBLE !!!

This light is everything I expected it to be; Super bright, perfect 'water-white' tint, and a nice beam pattern.

Due to the way the HAIII type three hard anodizing takes the red dye coat, the light does look different than standard smooth type 2 red anodized aluminum, having a rich dark burgundy almost metal flake red apperence (I like it).

I have tested it up against some known 80 lumen lights and it seems to be right on the button with at least 75 lumens output (brightest AAA light I have ever seen!), and run time on high was better than an hour on a 1000mAh NiMH with the light barely getting warm! :thumbsup:

I have been fairly vocal in the past in critiquing Fenix for introducing the L0D RB80 :thumbsdow pointing out that RB100 emitters cost literally only a few dollars more than Rebel 80's and that it was boneheaded stupid not to take advantage of a more efficient emitter in a tiny light like the L0D due to the fact that it was 'battery challenged' (due to it's single AAA power source), and therefore needed all the help it could get.

Ok fair is fair. I have to admit that this light, with a nice efficient Q4 emitter (at the standard price no less) including a nice little presentation box, is one hell of a great deal.

Way to go Fenix!!! :twothumbs

 

[daveman]

Good to know it's solid. I would jump in if not for the color; got to have black, no pink or red for me...

 

[Luminescent]

Good to know it's solid. I would jump in if not for the color; got to have black, no pink or red for me...

Truth be told, I also prefer most of my flashlights to have a simple black, dark gray, or satin-silver natural anodized finish, but variety is the spice of life as they say.

Think of it as 'aerospace red' not pink.

I guess no self respecting S.W.A.T. or Deltaforce wanabe would ever be caught dead with a 'pink' anodized light, but I am more the astronaut/fighter-pilot wanabe type, and blue and red dyed anodized parts are very common on aircraft and space vehicles, and, trust me on this one, this little red light would look right at home in the sleeve pocket of any flight suit.

I remember seeing a little 2AA golden anodized flashlight (that looked a bit like a modern 2AA mini-mag) in a Smithsonian air and space museum Apollo exhibit and thinking that this NASA light may actually have been what kicked off the whole precision milled aluminum flashlight revolution.

 

[veleno]

Has the L0D Q4 still got a dark ring around the hot spot?

 

[jasonsmaglites]

and super bright on 10440s too!

 

[Luminescent]

Has the L0D Q4 still got a dark ring around the hot spot?

The dreaded CREE dark ring is there allright, but it's not too bad in my light. It is quite noticable at some distances when shining the L0D Q4 on a white wall, but is not really noticable at all when actually using the light.

Here's a quick white wall beam shot at about 5 feet:

 

[veleno]

Thanks for the anwers!

 

[Lobo]

Nice pics!
I have to say that it looks much better on your pics than the previous ones I've seen. Nice catch!

 

[Luminescent]

and super bright on 10440s too!

My L0D is more than bright enough for me on simple NiMH cells, and the runtime charts for the L0D show that it is a bit brighter on Energizer L92 E2 lithiums (which unlike 10440's are 1.5 to 1.6 volts and are fully approved for use in the L0D).

So I don't plan to use 10440's, but those that do want to try it should be a little careful about 10440's until they get a feel for how they work in their L0D.

In general, when the L0D gets to hot to hold, it's time to shut it off.

10440's don't make the driver in the L0D 'work better' as some seem to think, they just bypass the boost circuit and force the light into direct drive, which pushes a LOT of current through the emitter and makes the light run insanely bright.

The only problem with this 'direct drive' situation, is that you are pushing the emitter LED right to it's upper limits (right to the ragged edge), without being able to control exactly how much current flows.

Once the L0D is in this 'direct drive' mode, the only thing controlling the current is the slight internal resistance of the battery and circuitry inside the L0D and the voltage differential between the battery voltage and the forward voltage drop across the LED (Vf).

It's not rocket science, just simple division based on ohms law.

It works like this.

Let's assume that the battery voltage is 3.6 volts and the Vf of the emitter is about 3.3 volts and that the total internal resistance of the battery and circuits in the L0D is 0.3 ohms.

The voltage available to drive current through the LED emitter is the difference between the 3.6 volt battery and the the 3.3 volt emitter Vf (which in this case would be 3.6 - 3.3 = 0.3 volts).

Ohms law says if we divide the voltage by the resistance (0.3 volts/0.3 ohms) we get the current (1 Amp in this case).

These are pretty reasonable numbers, and one Amp of current won't fry the emitter if you don't let the light run too long, but notice that if the Vf of the emitter drops even a few tenths of a volt the current could DOUBLE (ouch!).

I think one reason that Fenix went with a Q4 instead of a Rebel100 (aside from the fact that they probably got a good price on them), is that some folks have had trouble with the Rebel when using 10440's due to the lower Vf, and even though Fenix never approved the light for use with these batteries, they know that some folks will do it anyway and they don't want to get fried L0D lights back.

The CREE emitters like the Q4 do seem to average a bit higher Vf numbers, which usually makes them a little more likely to work with a 10440, but nothing is guaranteed because, as the production processes have improved, some of the CREE LED's are also showing much lower Vf numbers (lower Vf numbers give better ' Lumens per Watt', which is the true measure of LED efficiency, so the manufacture wants to drive this number down).

There are all kinds of silly ideas about this floating around, like the idea that you can't use a Q5 in a L0D due to the fact that the Vf is too high (when in fact this was just based on ONE BATCH that someone saw with really high Vf values). The truth is that they have bins for Vf, just as they do for color tint, because, although the manufacture would like to make every emitter perfectly consistent, there are variations, and the Vf you get is going to be a bit of a crap shoot (just like tint).

In simple language, all the above means you can't tell how much current will flow very accurately when you twist the bezel and turn on any given L0D with a 10440 cell in the light for the first time.

It could be as little as 500mA or as much as 2 Amps!

If your light gets too hot to hold in just a few seconds, while others brag about leaving their L0D running for several minutes, this is why.

EDIT:

Some have pointed out that the multi-level nature of the L0D provides protection, because, unlike some other Fenix lights, you don't completely loose control of MEDIUM, LOW, and HIGH modes when 10440 cells are used. The reason that other Fenix models can completely loose the low modes when used with higher voltage cells, is due to the fact that the brightness modes are done by current regulation in the boost converter circuit, so when the higher cell voltage hits and the light and bypasses the boost circuit, all control is lost.

In the L0D, the lower modes are handled differently. The L0D uses a separate PWM chopper circuit that is still in the circuit when the boost converter looses control due to the higher cell voltage, so some control is still available.

That's the good news, the bad news is that this is NOT a regulated circuit, just a simple on-off chopper that cuts down the apparent total brightness by turning the LED EMITTER on and off at about a 100Hz rate.

When the PWM switch is 'on' the resistance is extremely low, and the resulting pulsed current hit's the same 'peak' level as it does continuously when the light is set to 'high'.

This puts a lot of stress on the switch device if the Vf and battery voltage are such that high current flows as described above.

So, the way that the MODES control is done in the L0D creates both an advantage (you don't loose control completely when over-voltage 10440 lithium cells are used), and also a vulnerability (the PWM switch is switching much higher current pulses and may actually fail due to the overload).

I mention this because, folks should be aware that, if their L0D is getting VERY HOT, VERY FAST when set to high power mode, just selecting a lower mode may not provide complete protection, because the very-hot, very-fast situation is a sure indication that the Vf and Battery voltage are such that the light is pushing way too much current, and therefore the PWM switching MosFET is switching much higher current pulses than it was designed for and could fail at any time.

At least a few L0D's seem to have suffered near immediate failure when 10440 cells were tried, and I suspect that the reason was due to this switching device burning out. If the PWM switch MosFET fails 'open', the light will never light again until sent to Fenix for repair, and if it fails 'short' then all lower modes will not be available and the light will run full time at max brightness until sent for repair. I have seen at least a few posts indicating both these types of failures after 10440 cells were used, so this is more than just a theoretical issue.

 

[datiLED]

If anyone is interested, there is a good deal on the L0D Q4 in the B/S/T forum. FWIW, the seller is a really good guy, and I have dealt with him several times.

 

[PocketBeam]

I think the reason Fenix went with the Q4 is that they couldn't get the Rebels in the quantities they needed. Or at least this is what David basically said in another thread.

As for the color, well many people buy a black light that is hard to see in the dark. So they then put something that glows in the dark on it. Why not a light that is a little easier to see in the first place??? What good is a tool if you can't find it or you have a little trouble finding it when you need it?

I like the red, it is similar to a red sports car. It exudes performance...

I ordered two of these lights. One to give away and one to upgrade my current 10440 Lux III pocket light.

 

[Luminescent]

I think the reason Fenix went with the Q4 is that they couldn't get the Rebels in the quantities they needed. Or at least this is what David basically said in another thread.

I hear that old saw about availability of the Rebel 100 emitters over and over again, but I have actually ordered several batches of rebel 100's from Future Electronics (the official Lumiled dealer), and never found them to be out of stock (I thought they were out of stock once, but Future's search function was just fouled up, and I found them to be in stock once I figured this out).

If Fenix has any brains, they will offer BOTH a Q4 (or Q5) CREE version AND a Lumiled Rebel 100 version of the L0D side by side. Not only would this let them please the customers who have a preference one way or the other, but it would let them play 'dual source' games, playing off CREE against Lumiled to get the best pricing. Vendors are always willing to ****er more when they know you have the option of shifting your production to another supplier if you don't get the price you want.

As for the color, well many people buy a black light that is hard to see in the dark. So they then put something that glows in the dark on it. Why not a light that is a little easier to see in the first place??? What good is a tool if you can't find it or you have a little trouble finding it when you need it?

I like the red, it is similar to a red sports car. It exudes performance...

I ordered two of these lights. One to give away and one to upgrade my current 10440 Lux III pocket light.

I actually lost my last L0D-CE (which was black), because I walked away and left it laying somewhere that I shouldn't have, after using it to peek up inside some ducts while running some cables. So I was thinking along, somewhat similar lines, hoping that the RED version would stand out a little better so I would not be quite as likely to goof up and forget to pick it up and put it back in my pocket after using it.

As far as the aesthetics of the red color goes, I think the flight suit example, proves your second point that the red color can be very attractive and professional looking, and would actually be preferred in certain settings.

 

[geepondy]

I look at that light and I think it would be a good present for my girlfriend. But then I think she would never bother with rechargeables, she would only use alkalines, and alkaline's do terrible with that light, don't they?

 

[Luminescent]

I look at that light and I think it would be a good present for my girlfriend. But then I think she would never bother with rechargeables, she would only use alkalines, and alkaline's do terrible with that light, don't they?

Good point, alkaline cells have been shown to cut the runtime down by about half in continuous tests, but this seems to be true for ALL high performance lights due to their higher current demands.

But there are two things that will help a lot in the case of the L0D when used with alkaline batteries -

- First; the typical CPF runtime tests are run in a one pass continuous discharge which favors NiMH. With intermittent use, Alkaline batteries recover a lot of capacity that would be lost in a continuous test and give more total hours of use than shown on the runtime test.

- Second; the initial MEDIUM mode is the first one that comes up when you turn the light on, and thanks to the nice efficient Q4 emitter it is so bright in this mode that she will almost surely use this lower power mode 99% of the time. This will help out, because lower power modes favor the Alkaline batteries. Alkaline batteries actually have really good ultimate capacity at very low loads (in fact at very low loads it can even exceed NiMH).

NiMH cells give about three hours, in medium mode, and with intermittent use figured in, the Alkaline cells will probably also hit close to three hours as well (even though the continuous runtime tests only show about two hours for Medium mode).

So one of those giant packs of AAA Alkaline batteries from Costco will be more than a full YEAR's supply unless she is really going nuts using the light (and if she turns out to be that big of flashaholic, she will not mind dealing with a nice set of rechargeable NiMH batteries).

For heavy use of the high power mode, NiMH cells are definitely the most cost effective solution.

For disposable cells, this light really likes energizer L92 lithium, but they cost about 2 bucks apiece, and to get that good price you normally have to get them by mail order through the net.

I see that Battery Junction now has no-name E2 clone cells for about $1.59 each in quantity 10, so with luck these cells will get a little less costly in the future.

You could always get her 10 or 12 of the E2 or E2 clone cells to get her started (that should last a full year or more even with heavy use of the high power mode), but be sure to tell her not to waste them by using them in a MP3 player or some similar low power device, because in these applications these high cost cells don't really offer enough of an advantage over simple cheap alkaline cells to be worth the higher cost (alkaline cells work pretty well with low power loads, and L92 lithium cells really shine with higher current loads like a high performance flashlight).

Do try to come up with at least a single set of L92 Lithium batteries to put in the light when you present it to her because they not only last a lot longer, but they are noticably brighter than even NiMH, and significantly brighter in high mode than Alkaline, and so will create and incredible WOW FACTOR for this tiny light (I own a couple dozen lights and even I said WOW!). Make sure to get the real L92 Lithium E2's, as the wonderful folks at Energizer have started to use 'E2' for crappy 'sucker bet' Alkalines that offer only marginally better performance than cheap costco alkalines at 3 times the cost.

 

[Dances with Flashlight]

It works like this.

Luminescent - Explanations such as yours I can understand. Thank you for taking the time to lay it out.

 

[geepondy]

Luminescent, thank you for the post as well. You're right she would use it intermittently and really I wish it was a single stage with the medium as the default output. I suppose I could give it to her and put in a L92 lithium as an initial default first cell.

One other question, when these lights go out of regulation do they suddenly stop working (like my Huntlight) or do they just dim in a hurry. I have a strong dislikes for lights that just stop working.

I've been working a lot lately and am considering a flashlight purchase for myself for Christmas. I am thinking either one of the Fenix Rebels or a Surefire G2L. I'm sure the Fenix would provide better bang for the buck but I like the runtime and runtime curve of the G2L and think it would make an excellent car light. Can't really be a true CPFer and buy both at the current moment.

 

[Rzr800]

Luminescent - Explanations such as yours I can understand. Thank you for taking the time to lay it out.

+1 here; great post to tuck away in your gift set this Christmas. :santa:

 

[Luminescent]

Luminescent, thank you for the post as well. You're right she would use it intermittently and really I wish it was a single stage with the medium as the default output. I suppose I could give it to her and put in a L92 lithium as an initial default first cell.

One other question, when these lights go out of regulation do they suddenly stop working (like my Huntlight) or do they just dim in a hurry. I have a strong dislikes for lights that just stop working.

I've been working a lot lately and am considering a flashlight purchase for myself for Christmas. I am thinking either one of the Fenix Rebels or a Surefire G2L. I'm sure the Fenix would provide better bang for the buck but I like the runtime and runtime curve of the G2L and think it would make an excellent car light. Can't really be a true CPFer and buy both at the current moment.

As I mentioned, because there is no mode memory, if you turn the light off for more than a few seconds, it defaults to turning back on in MEDIUM. This means that it can be painlessly used as a one mode (medium only) light with no effort whatsoever.

Here is a link to the actual runtime graphs of the L0D

My L0D Q4 has more output, but maintains runtimes at least this good.

I also prefer lights that go into a nice low output 'moon mode' instead of just cutting off, and the L0D not only has a very nice 'moon mode' capability, but even more impressive, my L0D even starts back up again in 'moon mode' when shut off at very low cell voltages (which is a test that a LOT of lights fail, even if they offer some extended runtime in 'moon mode' if not shut down). :twothumbs

Note that there is a truely enormous 'moon mode' runtime when using Alkalines and a quite respectable one on L92 cells.

No light will give a super long moon mode on NiMH (the NiMH discharge curve cuts off too quick when they are fully discharged) but this little light does better than any of my others by a wide margin.

My experence is that NiMH do NOT cut off aburbtly as shown in the runtime plots (I suspect that the test was terminated when the light hit 50% on NiMH to protect the battery).

The general recomendation is to stop discharging NiMH cells at about 1 volt and never run them below 0.8 volts.

My personal experence is that running the NiMH cells flat doesn't usually hurt them in single cell lights like the L0D. The real danger is in multi-cell lights where the weaker cell will go dead first then be reverse charged by the stronger cell (this reverse charging can destroy the weaker cell). So I don't mind running the single cell lights like the L0D-Q4 into 'moon mode' on NiMH because the battery will just run flat with no danger of being reverse charged (but I am much more careful to cut off my multi-cell lights as soon as they start to dim).

If the NiMH runtime test had not been stopped as soon as the light started to dim, the L0D would have gone into 'moon mode' and run the cell all the way down below 0.8 volts (the NiMH 'moon mode' curve should look similar to the lower part of the curve shown for the L92 cell).

 

[swxb12]

Wow, great shot. Luminescent, is there some sparkle or glitter effect in that deep shine (like some car paints)?

In comparison the red in the stock photo provided by Fenix looks really dull like something dipped in red house paint.

 

[Luminescent]

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