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Sold/Expired SOLD - The Latest Stubby - SST-50 @ 4.2A

saltytri

Enlightened
Joined
Dec 20, 2008
Messages
531
$250 conus.

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My latest stubby raises the photon count from earlier efforts. A 4500K SST-50 is driven by a hybrid driver that gives the following tail cap currents measured with a Fluke 117 with heavy 4" leads: High = 4.2A; Medium = 1.22A; Low = .40A.

The driver is a ShiningBeam #1217 sandwiched in parallel with a 4x7135 board. Of course, the standard leads were replaced with #24 Teflon wire.

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The driver is packaged in a brass sleeve,

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which is held deep in the heat sink with a brass retaining ring. Those deeply recessed threads were cut with some blind faith, let me tell you. :eek:


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The emitter was reflow soldered onto a small raised pad on a substantial copper plate.

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The point of this whole exercise was to maximize the transfer of heat away from the emitter. The Mag, as well as many other lights, has the head threaded onto the body. The result is that for heat to get to the head, it has to transfer across an interface between the heat sink and the body and then across another interface from the body to the head. Since the Mag head has a lot of mass that really ought to be put to use for heat dissipation, it seems more efficient to screw the head to the heat sink directly. I'm no engineer but this makes sense to me.

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So, the heat sink has two threads, one to allow it to be screwed into the inside of the body and the other to mate to the threads inside the head.

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The end product looks similar to the standard Mag configuration but provides a direct path for heat to get across a single interface from the heat sink to the head. Also, note that the heat sink has a long, hollow section that extends well into the body to facilitate heat transfer along that path. The inside of the body is very smoothly bored to closely fit the outside diameter of the heat sink and thermal grease was applied in final assembly. The hollow section is sized to fit the front end of a 26650.

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The aft end of the 26650 is supported by a Delrin tube that is held firmly in the body with an o-ring.

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A smaller tube is provided for an 18650, though an IMR 26650 is the better choice for this light because of the current that it can deliver.

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The tail cap incorporates a McClicky.

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This conical reflector gives a nice beam with a strong hot spot that has fairly diffuse edges as compared with the more flat-bottomed P7/MC-E reflectors that also work well with the SST-50. This reflector, in conjunction with the warmth of the 4500K emitter, yields a luscious beam. Beam shots will follow if I can stay up late enough to take them.

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A UCL lens from flashlightlens.com rounds out the specs.

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Here are some beam shots.

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This one shows the cutoff at the edge of the spill - it's well-defined.

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The color is slightly warm - it looks especially good indoors for some reason.

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SmurfTacular

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Feb 16, 2010
Messages
704
Location
Orange County, CA
Re: The Latest Stubby - SST-50 @ 4.2A

Once again, you have made a beautiful stubby 1D Mag. You have earned yourself a solid reputation.

Good work :twothumbs
 

F250XLT

Flashlight Enthusiast
Joined
Dec 7, 2008
Messages
2,385
Location
CA
Re: The Latest Stubby - SST-50 @ 4.2A

Really nice, wish I had the funds to add this one to the collection.
 

waddup

Flashlight Enthusiast
Joined
Oct 29, 2008
Messages
1,269
Re: The Latest Stubby - SST-50 @ 4.2A

beautiful light,

High = 4.2A; Medium = 1.22A; Low = .40A.

very practical spacing of levels.

doesnt it make sense to try and keep the driver away from the heat?
 
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saltytri

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Dec 20, 2008
Messages
531
Re: The Latest Stubby - SST-50 @ 4.2A

Thanks, folks!

beautiful light,

High = 4.2A; Medium = 1.22A; Low = .40A.

very practical spacing of levels.

doesnt it make sense to try and keep the driver away from the heat?

That's an interesting question. What do the experts think? If the heat management system is getting the heat away from the heat sink well enough, the driver shouldn't get enough heat to do anything bad to it. The 7135 drivers are pretty efficient and don't generate much heat of their own on a single Li-ion.
 

ejot

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May 27, 2009
Messages
372
Location
East Fishkill, NY
Re: The Latest Stubby - SST-50 @ 4.2A

You keep outdoing yourself each build. This is fantastic. :thumbsup:

Regarding the mounting scheme for the driver, I think brass is a good choice especially if you ever sink any chips on the driver. Since most brasses have a lower thermal conductivity than aluminum, emitter heat will preferentially conduct through the aluminum and into the body instead of toward the brass/driver. (At least I think so, I'm far from a thermodynamics expert.)

Good luck with your sale, that is a killer deal given the amount and quality of work here.
 

saltytri

Enlightened
Joined
Dec 20, 2008
Messages
531
Re: The Latest Stubby - SST-50 @ 4.2A

Those are two 7135 drivers? Are they the same as the ones CPF member Download sells?

I believe that his multi-mode 8x7135 is the same as or very similar to the ShiningBeam unit that makes up half of my driver. (I've never had one of Download's units - not that there's any good reason not to get them from him but I've had such good results with many purchases from Bryan that I like doing business with him.) The other half of the driver is the single-mode 4x7135 1.4A unit from DX. These are very compatible with the SB board - the layouts make it easy to sandwich them.
 

saltytri

Enlightened
Joined
Dec 20, 2008
Messages
531
Re: The Latest Stubby - SST-50 @ 4.2A

Regarding the mounting scheme for the driver, I think brass is a good choice especially if you ever sink any chips on the driver. Since most brasses have a lower thermal conductivity than aluminum, emitter heat will preferentially conduct through the aluminum and into the body instead of toward the brass/driver. (At least I think so, I'm far from a thermodynamics expert.)

Thanks for the kind comments, ejot!

Your observation about the use of brass for the "pill" is very astute. I hadn't thought of that but it does seem sensible.
 

waddup

Flashlight Enthusiast
Joined
Oct 29, 2008
Messages
1,269
Re: The Latest Stubby - SST-50 @ 4.2A

Your observation about the use of brass for the "pill" is very astute. I hadn't thought of that but it does seem sensible.

agreed :twothumbs
 

F250XLT

Flashlight Enthusiast
Joined
Dec 7, 2008
Messages
2,385
Location
CA
Re: The Latest Stubby - SST-50 @ 4.2A

Wow, that looks great. If only I weren't a CR123 kinda guy...

I am a CR123 kinda guy, but had to buy THIS anyway. I have been using it every night, very solid build. Whomever buys this one, will certainly be happy with their purchase.
 

vestureofblood

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Joined
Jun 19, 2008
Messages
3,210
Location
Missouri
Re: The Latest Stubby - SST-50 @ 4.2A

Thanks, folks!



That's an interesting question. What do the experts think? If the heat management system is getting the heat away from the heat sink well enough, the driver shouldn't get enough heat to do anything bad to it. The 7135 drivers are pretty efficient and don't generate much heat of their own on a single Li-ion.

Let me start by saying that your work is astounding. At first glance I didnt think that much of the light, it just looked like any other grooved mag. But the work on the heat sink, and the recessed tailswitch sets this light in a class almost of its own. Very nice.

As far as heat IMO if anything I would say that brass pill is probly reducing the heat of the driver regardless of heat generated by the emitter. I use a set of 3x Shiningbeam boards in parallel for my SST-90. I like to use an aluminum plate between each board to dissipate the heat. I have found when these drivers heat up in high current apps the current drops after a short time. To me it seems the chance of "dammage" to the board though is zero in your case.

Again in my mind your work screams quality, and just plain good design. Thanks for sharing.
 

fyrstormer

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Jul 24, 2009
Messages
6,617
Location
Maryland, Near DC, USA
Re: The Latest Stubby - SST-50 @ 4.2A

You keep outdoing yourself each build. This is fantastic. :thumbsup:

Regarding the mounting scheme for the driver, I think brass is a good choice especially if you ever sink any chips on the driver. Since most brasses have a lower thermal conductivity than aluminum, emitter heat will preferentially conduct through the aluminum and into the body instead of toward the brass/driver. (At least I think so, I'm far from a thermodynamics expert.)

Good luck with your sale, that is a killer deal given the amount and quality of work here.
Heat moves in the direction of lower temperature, not lower thermal energy. The metal closest to the driver would need to have both a lower thermal conductivity and a higher specific heat (i.e. the amount of thermal energy needed to raise its temperature by another degree) in order to provide the maximum redirection of heat from the emitter away from the driver and into the aluminum shell of the light. In reality, brass has a lower thermal conductivity but also a lower specific heat (66% lower than aluminum!), so while it doesn't conduct thermal energy as well, it also takes less thermal energy to warm it up. So, even though aluminum conducts thermal energy 2.5x as well as brass, it also requires 3x as much thermal energy to raise its temperature the same amount. Unless there's something I'm failing to consider, that still means the brass pill will come up to temperature faster than the aluminum shell, even if only by a metric smidge.

That being said, it's very unlikely the driver would ever fail due to heat. Most surface-mounted electronics are designed to be able to cool themselves sufficiently through infra-red radiation alone.
 
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