# I call it the SL2K



## KBARK (Aug 7, 2007)

I finally finished up my single XML light. I still haven't found a good place to take beamshots so I'll have to add them later.


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## Toaster79 (Apr 5, 2010)

How will the battery holder cope with moisture? 

Nice build by the way!


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## KBARK (Aug 7, 2007)

I have a few ideas on a cover that would protect the battery. That is the only 18650 battery holder that I know of so I don't think anyone will make a snap on cover any time soon.

The body is sealed so as long as it is not totally submerged in water it should work in the rain.


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## Toaster79 (Apr 5, 2010)

But the contacts in the holder will ger rusty soon, so you'll have to swap it again and again. Same thing with the batteries :S


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## mfj197 (Jan 28, 2011)

KBARK, how did you go about colouring the square aluminium tubing? It does look a lot better than plain aluminium.


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## KBARK (Aug 7, 2007)

mfj197 said:


> KBARK, how did you go about colouring the square aluminium tubing? It does look a lot better than plain aluminium.


Do a search on here for rustolem textured enamel paint.


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## odtexas (Oct 2, 2008)

I like the battery mount. Light looks good too.
Put a little di-electric contact grease on the termnals and that will slow down any possible corrosion. You can get the grease at any auto parts store. It's used on light bulbs like blinkers, running lights,etc.

He could search for toaster oven as well and pull up that thread.


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## KBARK (Aug 7, 2007)

Beamshot....


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## yetibetty (Dec 24, 2007)

That's great output from a single LED. What current are you running it at?


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## KBARK (Aug 7, 2007)

I set the lflex for 3 amps max.


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## yetibetty (Dec 24, 2007)

Nice I like the LED tint too. But shouldn't it be called the SL3K as it's 3A?


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## mfj197 (Jan 28, 2011)

I do remember the toaster oven thread the first time around.  Unfortunately we don't get textured black rustoleum here in the UK (hammered only) but I'll probably just paint it with flat rustoleum and see how it goes.


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## mattthemuppet (Jul 16, 2004)

that's a tidy little light kbark and a really nice beam pattern. How does it cope with the heat at 3A?


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## KBARK (Aug 7, 2007)

mattthemuppet said:


> that's a tidy little light kbark and a really nice beam pattern. How does it cope with the heat at 3A?


When indoors I was a little disappointed with the new XML optics, but after I got the light on the trail I was very pleased with the beam pattern. The real spot has a good mix of spot and flood.

When I was taking the beamshots it never got above what I'd call "warm". The XML is glued to a 1 inch long piece of aluminum stock. That should be enough mass and surface area to dissipate the heat to the body and then the air.


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## mattthemuppet (Jul 16, 2004)

I agree, it does look like a really nice beam pattern. Nicer than the Regina imo.

Interesting about the alu stock - I guess that gives the light enough thermal mass to cope with dips in airflow. I was only asking as my single XM-L sled light gets uncomfortably warm sitting still at 1.5A and has a similar surface area as your light, perhaps even a bit more. It doesn't trip (set at 70C) with some airflow though.


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## Vancbiker (May 25, 2005)

KBARK said:


> When I was taking the beamshots it never got above what I'd call "warm". The XML is glued to a 1 inch long piece of aluminum stock. That should be enough mass and surface area to dissipate the heat to the body and then the air.


How long was it on for? Seems odd that it does not get hot (120F+) when stopped. The 1 inch long chunk will absorb heat, but once it is hot it stays that way a long time. It can transfer heat to the body well if it has good tight wall contact but it does not dissipate heat. The only way that heat is dissipated is to the air. A single XML at 3A needs a minimum of 9-10 square inches to keep cool with moderate airflow.


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## KBARK (Aug 7, 2007)

Vancbiker said:


> How long was it on for? Seems odd that it does not get hot (120F+) when stopped. The 1 inch long chunk will absorb heat, but once it is hot it stays that way a long time. It can transfer heat to the body well if it has good tight wall contact but it does not dissipate heat. The only way that heat is dissipated is to the air. A single XML at 3A needs a minimum of 9-10 square inches to keep cool with moderate airflow.


I'm not sure how long it was on for but the temp was in the 60's so that could have helped some.

I can hold it in my hand on high for about 5 mins before it gets too hot to hold. It is about 75 or so in my office right now. I have an infrared thermometer at home so I'll do some more testing.


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## yetibetty (Dec 24, 2007)

KBARK, would you mind also testing to see how fast it cools after turn off. It's not inportant, I'm just curious.

I agree with matt that you have a nice beam going on with that optic.


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## Ofroad'bent (Jul 10, 2010)

I bonded on some heat sink on my lights with thermal tape to help with the heat.
Where did you get the Rose Real Spot? Is it very different from the Laura RS?


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## KBARK (Aug 7, 2007)

yetibetty said:


> KBARK, would you mind also testing to see how fast it cools after turn off. It's not inportant, I'm just curious.
> 
> I agree with matt that you have a nice beam going on with that optic.


Ok, I'll do some testing on the warm up and cool down times, with and with out air flow. Should be interesting...


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## KBARK (Aug 7, 2007)

Ofroad'bent said:


> I bonded on some heat sink on my lights with thermal tape to help with the heat.
> Where did you get the Rose Real Spot? Is it very different from the Laura RS?


I'm hoping that a large internal heat sink will be enough without having to add external heat sinks or fins. I could probably increase the size of the heat sink from 1 inch to 2 inches if it would help keep the led cooler.

I ordered the Rose RS from Newark in the UK. It is similar to the Laura RS but seems to be optimized for the XML led. It has a "divot" in the center of the lens that the Laura RS doesn't have.


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## mfj197 (Jan 28, 2011)

KBARK said:


> I'm hoping that a large internal heat sink will be enough without having to add external heat sinks or fins. I could probably increase the size of the heat sink from 1 inch to 2 inches if it would help keep the led cooler.


Well, at the end of the day internal heatsinks won't help - it is purely a combination of emitter / driver heat dissipation (power) and external surface area. An internal heatsink just transfers heat within the light whereas the aim is to take heat away from the light. Having said that, I would imagine your light would be okay as it has a reasonable bit of surface area. How long is it?



> I ordered the Rose RS from Newark in the UK. It is similar to the Laura RS but seems to be optimized for the XML led. It has a "divot" in the center of the lens that the Laura RS doesn't have.


Interesting. It would be good to have back-to-back beamshots of the two - do you have a Laura RS you can try in a comparison shot?


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## KBARK (Aug 7, 2007)

The body is 3 inches long. The heat sink is press fit into the housing just like on Trouties "1" light so the heat sink transfers the heat to the body and then to the air. 

I do have a Laura RS that I can use to make some comparison beam shots.


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## Vancbiker (May 25, 2005)

At 3 inches long you'll have ~8 sq. inches of area to dissipate heat as the battery and mount cover more than 25% of the available area. You have ~9W of heat to get rid of. With cool air temps and a moderate pace you will be OK based on my experience with really small 6W lights. You need to be mindful of the fact that high temps are not kind to light output, electronics, and batteries and switch to a low setting when the pace is slow or stopped.


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## mfj197 (Jan 28, 2011)

You might be okay with heat then. As Vancbiker said above, you'd need a minimum of 10 or so square inches of surface area, and the straight aluminium tube and endcap would give you 13 square inches. Of course quite a bit of that is covered up with the battery holder, mount and rear switch, so the only way to find out is to try it, as you have been.

People like the Laura RS on the XM-L but I've found it to be a little short on throw so it would be interesting to see if your Rose RS is better in that respect. It does look a nice beamshot.

Edit: posted at the same time as Vancbiker!


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## Ofroad'bent (Jul 10, 2010)

Vancbiker said:


> At 3 inches long you'll have ~8 sq. inches of area to dissipate heat as the battery and mount cover more than 25% of the available area. You have ~9W of heat to get rid of. With cool air temps and a moderate pace you will be OK based on my experience with really small 6W lights. You need to be mindful of the fact that high temps are not kind to light output, electronics, and batteries and switch to a low setting when the pace is slow or stopped.


I've been building similar lights, but a bit shorter. My mount adds 2 square inches, and I add at least another 1 or two with heat sinks. Still hoping I can get the ideal XM-L build with an EasyDIY body in future.


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## KBARK (Aug 7, 2007)

Well the body length was basically determined by the battery holder length so I'm glad that it should all work out. I didn't really do any calculations, just thought it out in my head.

The run time on high (L5) is about an hour so I think it will be ran on L3 or L4 most of the time during use. This will increase the run time and reduce the temps.


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## jbflyfshr (Jul 24, 2006)

KBARK,

what driver is in there..? Looked at the other posts but didn't see it. Also, how is the mount attached?

JB


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## KBARK (Aug 7, 2007)

jbflyfshr said:


> KBARK,
> 
> what driver is in there..? Looked at the other posts but didn't see it. Also, how is the mount attached?
> 
> JB


The driver is a Lflex from taskled and the mount is attached with 3M VHB tape.


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## jbflyfshr (Jul 24, 2006)

Got it!

I can't decide on a cheapo from DX their XM-L light or building up 2 of these for my and the boy...always more satisfaction in a DIY but time and parts may outweigh that bit of fun

JB


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## mattthemuppet (Jul 16, 2004)

more thermal mass will help with smoothing out spikes in LED temperature resulting in dips in external airflow, but it won't make any difference in how quickly heat is transferred from the LED to the air. I wouldn't personally run more than 2A in my single sled housing as I use it all year round and it was throttling on the warmer summer nights with the trip point set to 70C and current at 1.5A, plus that was on the road. However, you do have the thermal protection in the lflex, so with that set at a comfortable level your light should be fine, whatever current you have it set at.

As for optic - I think the Laura and Regina are about equal on throw, with the Laura having a smoother beam pattern. Be interesting to see how the Laura and Rose compare. I don't like the divot thing though, that's one thing that annoys me about the CXP-RS.


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## KBARK (Aug 7, 2007)

I just did an unscientific no airflow temperature test. With the light on L5 (turbo) I was able to hold the light in my hand for 5 mins. With the light on L4 (high) I was able to hold the light in my hand for 30 mins (until I got bored). 

I don't think heat will be an issue...


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## KBARK (Aug 7, 2007)

Good news.... I found a battery cover!


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## Vancbiker (May 25, 2005)

KBARK said:


> Good news.... I found a battery cover!


No good without details!


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## KBARK (Aug 7, 2007)

The lead time on the cover is two weeks so it'll be a while before I can post pics.


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## mrradlos (Sep 3, 2010)

Did you find any covers?


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## KBARK (Aug 7, 2007)

mrradlos said:


> Did you find any covers?


Yes. I had to have them semi-custom made but they are a perfect fit. My camera doesn't take very good close up pics so I'm waiting on a friend to take some pics that I can post up.


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## rlouder (Jun 26, 2007)

Nice light. 

I think those who said the heatsink size doesn't affect heat dissipation may be wrong. I would think the bigger heatsink puts more surface area in contact with the housing, which should create a larger thermal path - assuming the whole sink contacts the housing.


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## mattthemuppet (Jul 16, 2004)

rlouder said:


> Nice light.
> 
> I think those who said the heatsink size doesn't affect heat dissipation may be wrong. I would think the bigger heatsink puts more surface area in contact with the housing, which should create a larger thermal path - assuming the whole sink contacts the housing.


a larger LED slug can increase the rate of heat transfer from LED to housing (although its increased mass will slow the time taken to reach equilibrium) but will do nothing for how quickly that heat is then transferred to the surrounding air, as that is purely a function of the effective surface area of the housing.

as long as the thermal path to the housing is capable of transferring heat from source to sink as quickly as the housing can transfer it to the air, there is no special gain from having a larger thermal path. It might affect cool down times, although that's getting into the realm of FEA and other people know a lot more about that than I do.


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## KBARK (Aug 7, 2007)

Here are some pics of the finished light with the battery cover and with out.


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## Vancbiker (May 25, 2005)

Excellent looking cover!


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## mrradlos (Sep 3, 2010)

That is just the cover I was looking for! Where did you find or how did you make it?


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## brankulo (Aug 29, 2005)

not sure how kbarks cover is done but here is what i am thinking how to do mine. i have two battery holder, will install batteries, tape it tight with clear tape and apply layer of bondo over it. than sand to desired shape and apply finish, most likely black paint.


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## KBARK (Aug 7, 2007)

I had the covers custom made, but I have a few extra that I could part with. Send me a pm.


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## mrradlos (Sep 3, 2010)

KBARK said:


> I had the covers custom made, but I have a few extra that I could part with. Send me a pm.


Private Message sent!


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## KBARK (Aug 7, 2007)

mrradlos said:


> Private Message sent!


PM replied, and a better pic with the cover.


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## Andy13 (Nov 21, 2006)

PM sent.


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## Alinvanc (Nov 15, 2011)

Does the paint affect the heat transfer ? I was thinking about painting my light, but wondered it the paint might slow down heat transfer.


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## KBARK (Aug 7, 2007)

Alinvanc said:


> Does the paint affect the heat transfer ? I was thinking about painting my light, but wondered it the paint might slow down heat transfer.


No, the paint doesn't seem to affect heat dissipation. I guess if you made a really thick coat it would, but a thin coat is better.


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## KBARK (Aug 7, 2007)

I can't believe it's been almost 6 months since I started on this "little" project! 

There are about 30 of these lights riding in and around Charlotte now. Thanks to George and all of my fellow diyers for your help.


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## mrradlos (Sep 3, 2010)

Thank you for sending me one of your battery holder and cover - I really like them:thumbsup: I filed my holder on both sides a little bit to make it easier to take the batteries out of the holder.


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## KBARK (Aug 7, 2007)

I'm glad you were able to put them to good use. That's the good thing about those battery holders, they will NOT let go of the battery. You can crash hard and I'm sure that battery will still be there.

I have been using tape to make a little "tab" on the batteries so that you can pop them out easier, even when wearing gloves. I can swap out batteries in less than 10 seconds.


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## Frede (Dec 7, 2009)

KBARK would you care to share the drawings of that neat little light or is it better to keep them for yourself now that you have startet a small production of them?

Also, how much would one light be if I were to purchase one from you?

Thanks!

Frede


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## KBARK (Aug 7, 2007)

Well, I'd rather not share ALL of my secrets... 

It's basically just a "slug in a tube" light that I put my own touches on. I didn't make any drawings, just planned it out in my head and made a few prototypes and went from there.

I've been selling them to friends locally for $85, that is without shipping though. Send me a pm if you want more info.


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