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Convoy S2+ has a challenger

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#1 UlfW

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Posted 28 July 2020 - 15:42

I have found a worthy challenger to the Convoy S2+ based on a 15W 4-chip LED.
https://www.ebay.co....ch/233620900023

The torch is wisely powered with a thicker 26650 cell instead of the 18650-cell used in the Convoy.
That makes it easier to get a battery with high capacity and a low internal serial resistance.
That is important as the torch use more current.
I will buy more quality batteries for these torches as the included ones had a rather high internal serial resistance.

The torch's mechanical design and build is good.
It has ring-shaped cooling finns around the front part to improve the cooling of the LED.
Attached Image: IMG_2183.jpg

There is a 2mm thick Ø40.9mm UV-pass filter that likely is a ZWB2 glass.
Attached Image: IMG_2186.jpg
Attached Image: Screen Shot 2020-07-28 at 16.39.00.png

In front of the filter there is a fluorescing rubber ring that helps to show when the torch is on.
For UVIF photography that can be placed behind the filter glass, to not be visible. replaced with an o-ring of suitable dimensions.
Attached Image: IMG_2184.jpg

The connecting parts in the front and rear modules appear to be well designed and assembled.
Attached Image: IMG_2187.jpg

The front part has a metallic reflector that easily can be removed.
The entire set of parts in front of the LED can be accessed and rearranged by unscrewing the front ring by hand.
Attached Image: IMG_2181.jpg

The LED chip is mounted on a 20mm star-shaped copper based PCB that is glued with thermal glue to the anodised aluminium-structure.
Attached Image: IMG_2180.jpg

The LED seams to be of good quality with nice wavelength distribution.
The wavelength-peak (blue) is more narrow than the one in the comparison Convoy (red) and with the peak almost 1nm closer to the nominal 365nm.
With the filters the remaining light at 400nm is ca 1/1000 of the peak at 365nm.
Attached Image: Screen Shot 2020-07-28 at 16.36.41.png Attached Image: Screen Shot 2020-07-28 at 16.36.57.png

I made an intensity comparison with both flashes on side by side at ca 45cm from a sheet of paper containing fluorescent whitener.
This image shows the two different hotspots created by the reflectors and it is quite clear that the Convoy is less powerful:
Attached Image: IMG_2174.jpg

With the reflector removed a very nice and even illumination can be obtained spreading cone-like as it is shielded by the front walls of the torch.
Attached Image: IMG_2176.JPG Attached Image: IMG_2177.jpg

When I tested the torch for adjusting the focus with a U-360 stack, illuminating the motif was much easier than with the small spot of the Convoy, No careful aiming was needed.

Edited by UlfW, 29 July 2020 - 08:19.

Ulf Wilhelmson
Curious and trying to see the invisible.

#2 Stefano

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Posted 28 July 2020 - 16:30

Very interesting. I would personally replace the fluorescing ring with a non-fluorescing one.

The LED seems similar to my super powerful one (https://www.ultravio...n-ebay-powerful). De-doming it (removing the lens) will make the beam tighter and more powerful (if you want a "thrower"). Otherwise you will have more "spill", the right choice depends on how do you want to use the flashlight.

The idea of using 26650 cells is nice, as you can get 5000 mAh ones, so the runtime will be longer of course.

#3 UlfW

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Posted 28 July 2020 - 16:53

View PostStefano, on 28 July 2020 - 16:30, said:

Very interesting. I would personally replace the fluorescing ring with a non-fluorescing one.
That was my initial thought too, but then I realised that the fluorescing ring might be useful, if you are not into UVIF but using the torch as a focussing aid, like I mostly do.
Then it is much easier to see that the torch is on and avoid draining the batteries unintentionally. I have sometimes forgotten to switch off my Convoys, being too focussed on focussing. ;-)

Edited by UlfW, 28 July 2020 - 19:14.

Ulf Wilhelmson
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#4 colinbm

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Posted 29 July 2020 - 03:22

That is a good find Ulf & thanks for the demo & comparison.
The fluorescing o-ring is a good idea, but if it annoys you, you could place it under the glass instead of on top.......

#5 dabateman

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Posted 29 July 2020 - 05:31

This looks excellent. I ordered two, as was actually cheaper than the recent 2 convoys I got from gearbest. A high intensity 365nm led is something I recently seem to need for other fluorescent experiments.



#6 UlfW

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Posted 29 July 2020 - 05:47

Be prepared about that the product packaging is primitive. It is just a rather simple paper box.
The Convoy sometimes comes in a nice product box and appear as a professional package suited for a shop display.
These new ones may not be finished all the way to package routines. The torches them selves appear quite OK.

I bought three and one of them had the battery put in reversed, but with a protective insulation tab at the pole. No harm done.
The correct orientation is with the battery's positive pole towards the LED.
I am confident that reversing the battery is not harmful for the torch. That only prevents it from working.
Ulf Wilhelmson
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#7 Andy Perrin

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Posted 29 July 2020 - 06:40

It looks very nice. One of the new people wanted to do UVIVF landscapes and such a powerful torch would be ideal for that...

Edited by Andy Perrin, 29 July 2020 - 06:40.


#8 UlfW

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Posted 29 July 2020 - 08:08

View Postcolinbm, on 29 July 2020 - 03:22, said:

That is a good find Ulf & thanks for the demo & comparison.
The fluorescing o-ring is a good idea, but if it annoys you, you could place it under the glass instead of on top.......
That is a smart suggestion, Col.
It works well.

One nice thing about these torches is that it is very easy to reconfigure them on the fly without tools.
By just unscrewing the front ring by hand you can remove or add filter reflector and rubber ring.
Ulf Wilhelmson
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#9 nfoto

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Posted 29 July 2020 - 11:07

"Do not post to Norway" -- bummer. We are sidelined with nefarious countries elsewhere. :excl:

#10 Stefano

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Posted 29 July 2020 - 11:45

View Postnfoto, on 29 July 2020 - 11:07, said:

"Do not post to Norway" -- bummer. We are sidelined with nefarious countries elsewhere. :excl:
What does this mean? I don't understand.

#11 colinbm

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Posted 29 July 2020 - 11:48

View PostStefano, on 29 July 2020 - 11:45, said:

What does this mean? I don't understand.

It means they don't believe in Santa Claus.

#12 nfoto

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Posted 29 July 2020 - 12:04

The seller will not ship the torch to my country.

#13 Stefano

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Posted 29 July 2020 - 12:07

Ok, now I understand.

#14 JMC

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Posted 29 July 2020 - 13:45

Thanks for the heads up on these Ulf - I've ordered a pair.
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#15 UlfW

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Posted 30 July 2020 - 16:47

I have a warning about removing the reflector.

Today when I wanted to measure the PCBs final on-temperature, I noticed that the PCB is not glued with thermal glue, as I previously assumed.
The white stuff I thought was thermal glue is thermal paste.
Without the reflector I can slide the PCB a bit sideways.

The PCB is normally pushed against the thermal paste and internal heat-conducting aluminium housing by the reflector, filter, rubber ring and front locking ring.
With everything in place this is a very good thing, because it adapts to mechanical movements due to temperature changes.

Without the reflector, the PCB is kept in place only by the stickiness of the thermal paste, and there is a slight risk that the thermal contact decreases.
As the gap with thermal paste is rather thin the PCB is still held in place rather well, but not as good as when it is secured with the reflector.

Edited by UlfW, 30 July 2020 - 16:49.

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#16 SteveE

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Posted 13 August 2020 - 01:03

I am getting ready to order mine. For those who have already received theirs:
If I buy the version with the battery and charger, are the batteries of decent quality?
I don't want to experience a corner cutting Li-Ion battery explosion first hand.

Edited by SteveE, 13 August 2020 - 02:58.

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#17 Cadmium

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Posted 13 August 2020 - 01:30

I have had one for about a week.
Often the same charger that charges the 18650 batteries (for the Convoy S2+) will also charge the 26650, but you should check the info for your charger, because I am not sure if that is always true.
I was trying to figure out earlier today what filter it actually has in it. I gave up. I don't know if it is something closer to UG1/U360 or UG11/U-340.
You can feel more heat from the front of the torch, but I have not left it on long enough to see how much it heats up the front of the torch metal yet, but it does have a "HOT" warning on the front.
Definitely bigger than the Convoy S2+, not really very pocket sized like the Convoy.
I performed a no-filter / no-reflector comparison, same distance, the new no-name torch is definitely brighter.
Personally, I will remove the filter that came with it and install U-340 2mm instead, just so I know what I am getting, but it should work nicely the way it is also.

PS: For all you geeks out there, the thread on the front of the torch is 42mm, so you can use a 42mm to 52mm step up ring to attach a U-340 52mm x 2mm filter to the torch in a pinch.
Remove the torch front ring, remove the original filter, use a 42mm retaining ring, or an 42mm to 39mm step down ring as a spacer to hold the reflector in the torch, then install the 42mm to 52mm step up ring.
I have a 42mm to 52mm step up ring, but looked all over for it, can't find it.

#18 Andy Perrin

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Posted 13 August 2020 - 02:02

Ahhh, thanks, Cadmium, I was wondering how to find the right size filter, but it seems I have what I need already. Can I substitute UG11 2mm?

#19 UlfW

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Posted 13 August 2020 - 03:29

View PostCadmium, on 13 August 2020 - 01:30, said:

I was trying to figure out earlier today what filter it actually has in it. I gave up. I don't know if it is something closer to UG1/U360 or UG11/U-340.
The transmission spectrogram in my post above clearly indicates that the filter is a UG1/U360 "equivalent" filter.
" There is a 2mm thick Ø40.9mm UV-pass filter that likely is a ZWB2 glass."
That is good enough most of the time for UVIF.
Ulf Wilhelmson
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#20 Cadmium

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Posted 13 August 2020 - 03:36

Andy, Yes you can used UG11 2mm, same as U-340 2mm on the torch, but the UG11 is more expensive, it is about the second or third most expensive filter glass that Schott makes.
As long as you are using 2mm, I see no real need to use UG11 instead of U-340, but they work the same at that thickness.

Thanks Ulf, missed that.
Odd, does the filter have a little blip around ~430nm~ ?
Using U-340 will cut brightness ever so slightly from using UG1/U-360, and I won't venture to guess about ZWB2 because I don't use that stuff ever, like you say, "good enough",
but I might as well use what I know best and cut things exactly before the visual range to make sure it is totally clean.
The 430~ blip concerns me a little... someone else was questioning that also. So I am changing the filter on mine to U-340 2mm. Rock solid visual cut-off.
I like the torch though, so far. Your 300 range scan looks good to me.
I already made a case of two, but I have to make the U-340 40.9mm x 2mm filters still.
These are even bigger than a Convoy C8! So they require a bigger case.

Personally, I don't like the glowing O-ring. Looks nifty, but I don't want it.
You don't need it, except for water.
Make yourself a regular black rubber O-ring, get a larger O-ring if you cant find the exact same size, cut it and glue it back together the size you want, or get some O-ring cord,
cut it, and glue it for the ring size you want.
Get rid of the glowing ring. It is not as cool as it looks. I would eliminate it.

Edited by Cadmium, 13 August 2020 - 04:08.