DealExtreme 18650 Q5 "Piston" flashlight: first impressions

[Fallingwater]

I just received this flashlight.
The "Piston" nickname is unofficial, by the way. It just looks kinda like a piston to me.

The good:

I was expecting something with the size and heft of my U2 clone, but it's considerably smaller and much lighter. The Piston with a 18650 in it weighs a bit less than the U2 clone without.



This gives the U2 clone a lot more aggressor-smacking potential, but since the Piston is not meant for any sort of tactical duty the lighter weight is a good thing.

I'm not usually one to choose things for their aesthetics, but it must be said that the Piston just plain looks nice. Not many flashlights look as if they ought to be inside an engine.

The threading on the tailcap feels ok, even if a bit tight. The threads are pre-lubricated, and there's an o-ring that seems to be doing its job.

It has memory, which DX didn't specify. It was a pleasant surprise; you don't have to click through modes every time if you're ok with using it in the mode you used it last.

DX's page says the modes go Mid > Low > High > Strobe > SOS, but in my light they go Low > Mid > High > Strobe > SOS, which makes more sense to me.

It seems bright.

The bad:

The beam is by far the worst I've seen on a Cree flashlight, and this includes my originally-intended-for-Luxeons MXDL 123. It's uneven and very ringy. The plastic reflector is obviously not a good choice.
It's not a crippling problem, because when you're actually using it (as opposed to just pointing it at a wall) the beam pattern's relevance decreases greatly, but still. One of the many reasons I steer clear from incandescents is to avoid seeing this sort of crap.

The deity-damned strobe and SOS modes are there and there's nothing you can do to avoid them (update: actually there is. Read the following posts for more details about this). This was expected, of course, but it's still bad.
I can just believe strobe mode could be useful to someone, but SOS should be banned from all flashlights everywhere, with the death penalty for anyone who builds one with that mode regardless.
Well, maybe the death penalty is a slight exaggeration, but a severe whipping is definitely in order.

The ugly:

The switch is the definition of the term "craptacular". It's a two-stage, which means two switching actions are needed for every mode change. It might be possible to depress it partially to change mode, but I can't tell you because I didn't have enough time to test it before it failed completely.
For a few times it didn't want to pop back out when pressed, and only strongly whacking it eventually caused it to relent. Then whacking no longer did it and it got stuck in pressed-off mode, after not even five minutes from the moment I started using it.

This is also the reason why there are no beamshots and no comments on the light level. I'll post some once I manage to unstick it, or replace it completely.

Other notes:

There's a slight whining noise when it's in low mode, but it's not very loud.

For the very short time while it was actually working, I noticed the flashlight sometimes randomly turns off for a fraction of a second while in low mode and being moved around. I'm not sure if it's a driver defect of a switch defect, although I'm inclined to believe it's the latter.

Conclusions so far:

I'm pretty disappointed. If this was a $12 light I'd go "eh" and consider these shortcomings the price to pay for cheapness, but $25 is supposed to get you better quality from DX. The U2 clone is actually cheaper, and works rather better.

I'd send it back to DX for a replacement if it shipping didn't take so darn long. I'll try to fix the switch myself and see what can be done for the beam. Maybe I can get a proper metal reflector for it.

 

[IcantC]

Nice writeup. Looks like a wannabe Z2

 

[shinbone]

You know you will order something else from DX and you would have to wait for it anyway, I'd recommend trying to exchange it. I got the C2 Q5 light that came out at the same time and am very happy with it, you might consider it as a replacement.

If you decide not to hassle with a return, swap the Q5 emitter with your U2 clone and at least get some joy from that little upgrade. The Piston can then become that light you don't mind rolling around in the crawlspace of the house or dropping while working on your car.

I'm not familiar with your modding background, so I'll throw these out as possible ideas, perhaps ones you are already aware of:
-The Sandwhich Shoppe website has some good reflector reference pdf files on their site, hopefully you can find a close match.
-There was a sputter technique that might help the beam if it's a smooth reflector, some type of Krylon spray if I remember correctly.
-Some people have been able to bypass the multi mode functions on driver circuits by relocating the (-) emitter lead, maybe a fix there if you want a single function light. A pic of the circuit might be enough for these gurus to help figure out where the sweet spot is.

Thanks for the highly informative review!

 

[Sgt. LED]

Wow, I no longer have to wonder about this interesting looking light. It is utter crap, thanks for taking the hit for the rest of us!

 

[garence]

Wow, I no longer have to wonder about this interesting looking light. It is utter crap, thanks for taking the hit for the rest of us!

Agreed -- I'd also managed to spot this one and the shape, thought not ergonomic, is really striking to me. I had it on my spreadsheet of future light possibilities--stricken now, thanks to your advice. Hopefully DX will be good about taking it back.

 

[Fallingwater]

I've managed to unstick the switch. It still needs unsticking every three or four clicks, so it's a temporary solution at best, but it allows me to operate the light. It's possible, as I thought, to depress it partially to change mode.

Some beamshots follow.

Here it is against the U2 clone:



The U2 has a slightly ringed beam itself, but it only appeared after I'd disassembled and reassembled the head. Another member told me it was normal with this light, and adjusting the position of the pill fixes it. Adjusting the pill requires unscrewing of the battery tube, though, and that is problematic because there's a crapload of threadlock.

Edit: I noticed the picture doesn't give justice to the difference. I tried snapping a few more shots, but it just doesn't come out right. The U2's beam is much cleaner than the Piston's in reality. In additon to the rings, the Piston's beam also has an irregular hotspot, which you can't see in the pictures due to lack of focus or overexposure.

Anyway, back to the Piston: it's definitely whiter than the U2 (not immediately apparent in the rather overexposed beamshot), but I can't say which is brighter just by looking. Update: actually, I can. If pointed at a surface far enough away (as opposed to the wall at one metre) it's quite clear that the Piston is noticeably brighter than the U2, and the beam is less bluish.

Fortunately, I own a light meter. It gives substantially higher readings with the Piston, and since the center of the beam is of roughly the same size it should be a good indication of relative brightness.

At a distance of one metre the Piston reads about 7000 lux, while the U2 reads about 5500. I think these readings are way higher than they should be; I may just have a wonky meter, or maybe I'm doing it wrong. Whatever the case, the difference still shows that the Q5 emitter is not there just for show.

More beamshot goodness:



These are both of the Piston in full power mode, but with different shutter speeds. I couldn't decide which is better to show the beam artifacts, so you get both.

At full power and from a freshly charged cell the Piston draws 980ma at full power, about 200ma at medium and 70 at low. The U2 draws 900 at full power; I don't know how much it draws at low because low mode is provided by a resistor in the tailcap. I could rig up some wires and take a measurement, but a severe attack of laziness is preventing me from doing that.
There is a certain level of approximation here, as my multimeter doesn't show single milliamps on the 10A scale.

Oh, but there's more weirdness.

The flickering in low mode is caused by the driver. Whenever low mode is activated it waits a bit more than a second and a half, flickers once very quickly, waits another second and a half, flickers a second time with a longer and definitely more noticeable moment of darkness, waits yet another second and a half, flickers once again quickly, and then it stays on.

In medium mode it only does the first short flicker once, then it works ok.
Full power mode has no flickering whatsoever.

Considerably more weird is that I managed to get it to skip strobe mode and SOS entirely. I was happy about that, until during more testing it decided it wanted to have not one but many strobe modes.

All this tells me that this light does not in fact have a 5-mode driver. Instead, it has one of those horrendous hyper-multimode drivers with an interface, akin to the one in this thing. The flicker in low mode is the driver giving its "change group" signal. If you power-cycle the flashlight after the second (long) flicker but before the third (short) one, it goes to the next group.

I've played around with it a bit, and here are all the modes I've managed to find:

Group 1: low > mid > high > fast strobe > SOS (the flashlight comes set in this group)

Group 2: low > medium > high (no strobe or SOS modes whatsoever)

Group 3: low > medium > high > fast strobe > pulses of five fast strobes > medium strobe > slow strobe > SOS

Now that I've discovered this, I can't decide what to do.

On the one hand I hate hyper-multimode drivers with a passion, because having to navigate an interface in order to operate a flashlight is cumbersome and inefficient. When I discovered the presence of the groups the first thought that crossed my mind was "this goes back to DX".

On the other hand, I'm loving the no-strobe no-SOS group. It's good to be able to change brightness level without having your eyes assaulted by a full-power strobe in the process.

The only problem is that it's all too easy to switch group by mistake. I wish there was a way to lock the current group.

 

[Fallingwater]

After using it a bit I've come to the conclusion that it's not actually a bad light after some tinkering.

Replacing the switch cures the biggest problem... which, of course, you might not actually have if your light has a decent stock switch. Some reviews have popped up on DX and nobody complains about the switch, which leads me to believe it's not a problem common to all Pistons.

Once the switch is taken care of, and the light is set in the three-mode group, it's pretty pleasant to use. You don't really notice the ringy output when you're using it actively (I'm still going to order a replacement reflector), and that Q5 is really rather powerful.

I can say my overall opinion of it has improved considerably, although it'd still be worthless if I couldn't, or didn't want to, tinker with it to replace the switch.

 

[Fallingwater]

Having previously replaced the switch with an external contraption, which worked but which didn't make it a pleasure to use it, today I removed the external switch and installed a replacement switch from DX (this one, which fits just fine once you grind off some of the plastic and bend the tabs upward).

I actually like it now. The beam is still pretty ugly, but you don't really notice it when you use the light, and the three-mode group is a blessing. The group-changing blink doesn't happen too soon, so I don't find myself changing group by mistake.

It also has an excellent candle mode. You can unscrew the upper part of the head, and you get the bare emitter with no metal around it. You don't have to worry about losing the reflector and lens, since a retainer ring keeps them in place.
There is a small and very easily loseable plastic ring on the emitter, to prevent it from being shorted by the reflector. However, since the reflector is plastic and the conductive end is just paint, a kiss from the bench grinder is all it takes to remove it, with no loss of performance from the reflector when installed. This way you don't need to worry about the plastic ring and you can use candle mode anywhere.
Kinda makes you wonder why they used a conductive reflector in the first place...

The Piston has become my main in-house light now, and I carry it outside when I know I'll need more light and runtime than my NDI can provide.

I'd still prefer the U2 clone to it in an emergency, though, since I'm pretty sure it can handle more physical punishment.

 

[wgibso]

Fallingwater, thanks for the reviews and advice on dx 9634. I've just ordered two of these to use as dual bike headlights. I like how small and light they are, and the multi-modes will come in handy as the mission changes according to conditions: high mode to see in the pitch dark, low on intermittently-lit bike trails, strobe to be seen in traffic, etc. in various combinations.

I'd like to leave one as is, for throw, and to mod one for a more floody light. Have you (or anyone else who owns these or a similar light) experimented with diffusion? From what I've read, the UCL with Light Diffusion Film at flashlightlens.com spreads the beam, but how much? Anyone tried it for this kind of application?

Thanks!

 

[Fallingwater]

I haven't, but candle mode will give you perfect flood (though no throw at all). If what you want is a mix of the two, you probably need another reflector. On this subject, I still haven't gotten around to ordering a suitable metal replacement...

 

[Jarl]

I was looking at a piston for a super throw monster (with some modding). You just put me right off it (my finances survive another day!!)

 

[r-s]

PMJI...

I spent a nontrivial chuck of the afternoon wading through DealExtreme's driver board offerings -- many of them have "features" of the type complained about in this thread (and complained about by me, in subvocalized muttering as I read through their listings). (I am trying to find a few driver boards for a few build-it projects.)

Anyway... one thing I noticed in some of the comments accompanying the drivers was the undocumented ability to bypass the stinkinblinken stuff, without any great trouble (i.e. resolder one wire).

I would wager that there's a good chance they're using one of those same boards in this flashlight (the feature set sure sounds familiar), and if so, you might want to dig through their listings -- the comments in particular -- to see if you can strap this sucker into "flashlight-only" mode.

If worse comes to worst, you could probably replace the driver board (they're remarkably cheap!) to get rid of the unwanted features (and then sell the board on fleabay "LQQK! Upgrade your LED Flashlight! FEATURES! $10.00 BIN!"

Yeah, I'm cynical and jaded (but ethical<g> -- I wouldn't do that even knowing that *someone* would likely bite. I'd just toss the old board into a drawer to keep for backup use).

 

[Khaytsus]

It's really annoying that almost every flashlight, cheap or expensive, the highest failure point is the switch. Cheap lights tend to have switches which barely work from the start, better switches either give out after a while or immediately die after being dropped, etc.

It would be nice if higher end lights could use bombproof switches which won't just randomly fail and are more drop-resistant, and it'd be nice if cheap lights at least used switches that would work for a reasonable amount of time.

I know pennies per part adds up fast if you're making 200,000 but my opinion is that I'd pay $.50 more for that additional $.03 for a better switch.

 

[LukeA]

Fallingwater, thanks for the reviews and advice on dx 9634. I've just ordered two of these to use as dual bike headlights. I like how small and light they are, and the multi-modes will come in handy as the mission changes according to conditions: high mode to see in the pitch dark, low on intermittently-lit bike trails, strobe to be seen in traffic, etc. in various combinations.

I'd like to leave one as is, for throw, and to mod one for a more floody light. Have you (or anyone else who owns these or a similar light) experimented with diffusion? From what I've read, the UCL with Light Diffusion Film at flashlightlens.com spreads the beam, but how much? Anyone tried it for this kind of application?

Thanks!

Strobe will only blind oncoming traffic, making a dangerous situation for everyone.

 

[Gryloc]

I have one of these on its way (I think). When I first saw it, I thought that it was very nice looking. I, too, am the type that is turned off by excessive, bulky aluminum protrudy tactile bits, so this will be a pleasant change. Another thing that struck me by your review is the size!

I was worried about the initial review, but I am pleased to hear that if you do the usual DX/KD fixes and maintenance on the light, it is not that bad. The ringy beam is sort of a bummer, but I am thinking of swapping the LED to something like a Seoul P4 or an 0200 TFFC K2. Some day, when I have access to a lathe, I would like to turn a beefier heatsink for this light, then shorten the bezel and re-thread it. This would be a nice host for a 18650 powered tri- or quad- Rebel 0100 light, using either the McR-10R or McR-12R reflectors from the Shoppe. Until then, maybe I can mod one of these with my Seoul P7. All I would need to do is trim down the plastic reflector, or add a nicer aluminum one, and remove the driver circuitry so it is atleast running in DD. We'll see.

Can you measure the diameter at the battery tube for us? I wonder if a different tailcap can be used to replace that ugly thing, or if it can be trimmed down to be flush with the rest of the battery tube. What do you think? Thank you for the detailed reviews! :thumbsup:

-Tony

 

[Fallingwater]

I was looking at a piston for a super throw monster (with some modding). You just put me right off it (my finances survive another day!!)

Did you read the rest? With the switch replaced and with the three-mode group active, I find it a pretty good light.

Anyway... one thing I noticed in some of the comments accompanying the drivers was the undocumented ability to bypass the stinkinblinken stuff, without any great trouble (i.e. resolder one wire).

I would wager that there's a good chance they're using one of those same boards in this flashlight (the feature set sure sounds familiar), and if so, you might want to dig through their listings -- the comments in particular -- to see if you can strap this sucker into "flashlight-only" mode.

I'm not interested in doing this.
It'd be good if it could be forever locked in the three-mode group, but I need the modes. Always-high is a big turnoff for me.

If worse comes to worst, you could probably replace the driver board (they're remarkably cheap!) to get rid of the unwanted features (and then sell the board on fleabay "LQQK! Upgrade your LED Flashlight! FEATURES! $10.00 BIN!"

The other modes are not much of a nuisance. Only thing that irks me a bit is the blink in low power mode as it signals it's ready to change group, other than that I never find myself in a mode I don't want to use.

I was worried about the initial review, but I am pleased to hear that if you do the usual DX/KD fixes and maintenance on the light, it is not that bad.

Order a 5-pack of replacement switches to go with the light. Chances are you'll need one sooner or later.

The ringy beam is sort of a bummer, but I am thinking of swapping the LED to something like a Seoul P4 or an 0200 TFFC K2

I don't know if the stock reflector will work well with those. For all I know it might give an even worse beam.

Some day, when I have access to a lathe, I would like to turn a beefier heatsink for this light

Heat sinking is pretty good IMO. There are even cooling fins behind the reflector (possibly only eye candy, though).

Can you measure the diameter at the battery tube for us?

Not right now, but I can tell you a protected Ultrafire 18650 fits tight enough that I have to shake the light to get it out.

I wonder if a different tailcap can be used to replace that ugly thing

I find the original tailcap fits well with the design of the light.

I think I'll try butchering some reflectors off old incandescent flashlights currently in the junk box in an attempt to find one that will give a better, floodier beam. I can stand the rings, but te original reflector doesn't have enough spill for my tastes.

 

[Jarl]

Did you read the rest? With the switch replaced and with the three-mode group active, I find it a pretty good light.

Yeah, I read that, but im thinking the VB-16 would be a more useful light generally.

 

[wgibso]

Strobe will only blind oncoming traffic, making a dangerous situation for everyone.

Strobe isn't brighter than constant-on, it just catches the eye better. If a driver is actually blinded by my bike headlights, I'm probably already on his hood.

And let's remember, even as bright as these lights are, they're not brighter than car headlights. People don't veer out of control every time a car passes.

 

[Fallingwater]

Something useful I just found out after connecting the Piston to my lab power supply: it still draws a tiny amount of current at 3.2V (20ma, still enough to be rather uncomfortable when looking straight at the emitter), but it stops working entirely at 3V. At 3.1 it draws one milliamp very briefly at power-on (no visible light), then drops to zero.

This means it's safe to use with unprotected 18650 cells, as it'll stop working before the cell gets overdischarged.

 

[LukeA]

Strobe isn't brighter than constant-on, it just catches the eye better. If a driver is actually blinded by my bike headlights, I'm probably already on his hood.

And let's remember, even as bright as these lights are, they're not brighter than car headlights. People don't veer out of control every time a car passes.

I think you're thinking of a maybe 1- or 2Hz strobe of a few lumens, not the strobe on this light, which would be in the neighborhood of 300 lumens and 6Hz, a frequency in the range best suited for visually incapacitating humans. I think that that is going to get someone hurt.