# Finally, a Real Light (TM) for a Real Man (TM)



## mattthemuppet (Jul 16, 2004)

None of this machining nonsense, XYsandwhatsits and all that jazz. I'm going to be rending a light with cold bare hands (cue Charlton Heston voice), some entirely inappropriate tools, a dash of incompetence and even my teeth if necessary.

So, after that intentionally inflammatory and attention grabbing title, can anyone guess what this simply awesome light will be made out of?


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## BKruahnndon (Jul 17, 2009)

hopes and dreams?


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## mattthemuppet (Jul 16, 2004)

nope, not bright enough


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## bobdotorg (Feb 8, 2011)

A quad XM-L urologist's scope?


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## unterhausen (Sep 28, 2008)

unicorn tears?


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## mattthemuppet (Jul 16, 2004)

bobdotorg said:


> A quad XM-L urologist's scope?


ooh, interesting. I did read proctologist for some reason, which is a touch disturbing. Either way, bacteria, cancer, anything really wouldn't stand much chance with that..


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## find_bruce (May 8, 2011)

Edited: delete failed attempt at humour


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## mattthemuppet (Jul 16, 2004)

unterhausen said:


> unicorn tears?


hadn't thought of that actually.

Sadly, now I've hyped it all up the answer is much more prosaic:










however, if I had to choose between a small lump of aluminium and 6ft of 1in.sq. tubing with which to fight an angry bear, the tubing would get it every time (quickly followed by me, I guess)


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## mattthemuppet (Jul 16, 2004)

might as well get into the meat and potatoes of it.

Meant to take a pic of the 3 sled pieces but it was a bit boring so I didn't.

here's the back end of the sled, about to be chopped up










after being chopped up










and with its matching front sled pieces loosely bolted on










driver (h6flex) goes in the middle, LEDs on the end and switch/cable/remote cable go on the other end (top, in the picture).

Have to cut the outside bits (from my bear-beating, Real Man 6ft length of tumultuous tubing) off tomorrow and haphazardly cut them to size


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## bobdotorg (Feb 8, 2011)

I'm making a similar build, but using a DIY Class A Amp heat sink as the base. A hacksaw, file, drill and tap should get most if it done. Maybe I can finally put the cordless Dremel to good use.


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## mattthemuppet (Jul 16, 2004)

find_bruce said:


> Oh oh oh I got it.
> 
> You are going to make a tail light, by using your hands to take one of these
> 
> ...


how do you guys come up with this stuff? Genius 

Funnily enough (hence the morbid dwelling on proctologists), I heard a funny saying the other day:

"may your proctologist have thin fingers"


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## mattthemuppet (Jul 16, 2004)

bobdotorg said:


> I'm making a similar build, but using a DIY Class A Amp heat sink as the base. A hacksaw, file, drill and tap should get most if it done. Maybe I can finally put the cordless Dremel to good use.


neat! You'll have to do a build report so we can see how you did it.

Sadly, I have all the imagination of a snail, so all my lights are made out of exactly the same material. As a technological improvement akin to the invention of the steam engine, I am now using a jigsaw with a metal blade to cut off the lumps. Takes a couple of minutes and the bits end up relatively square, as opposed to 30min plus and like an Escher drawing using my Dremel


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## odtexas (Oct 2, 2008)

Long days of Northern Hemisphere Summer are upon us. Building slows. 
Order your parts now from DX and KD and maybe they will be here in time to build lights for winter riding season.
In the mean time be thankful for hyperactive worm wranglers hacking lights out of tubing and keeping this forum going.

Appreciate the entertainment and good luck with the new light. Thanks. :thumbsup:


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## Goldigger (Nov 6, 2009)

Come on Matt please talk x y and z, its the only language I understand


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## klynk (Apr 18, 2010)

New bombproof light with 10*XML?


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## mattthemuppet (Jul 16, 2004)

odtexas said:


> Long days of Northern Hemisphere Summer are upon us. Building slows.
> Order your parts now from DX and KD and maybe they will be here in time to build lights for winter riding season.
> In the mean time be thankful for hyperactive worm wranglers hacking lights out of tubing and keeping this forum going.
> 
> Appreciate the entertainment and good luck with the new light. Thanks. :thumbsup:


don't forget the boyz dahn unda, they're starting to hit "winter" about now 

funnily enough, I ordered some of the parts for this light back in January, I've just been futzing around doing other bits and pieces in the meantime (although I do now have a very neat rear facing dome light for my Focus wagon). Plus, my helmet light is actually pretty decent, it's mostly the fact that I ride v. rocky trails but can't see the rocks (no shadows) that prompted building this light. And the fact that it'll piss off my riding buddy with his Seca 700 :devil:

on the subject of funny, I built my commuter light when it was ~ -20C in the garage and you could barely see me under all my clothes, now it's ~ +30C and I'm getting bits of Dremel disk pinging off my chest. Crazy.


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## mattthemuppet (Jul 16, 2004)

Goldigger said:


> Come on Matt please talk x y and z, its the only language I understand


and to think we're both from the Motherland, sniff


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## mattthemuppet (Jul 16, 2004)

klynk said:


> New bombproof light with 10*XML?


I wish! On both points!

It will however have a completely mismatched set of hacked up computer heatsinks cooling (possibly) it down so it doesn't self combust


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## TTGV (Oct 31, 2008)

computer heatsinks...

+1 !!:thumbsup:

and Artic Silver epoxy and lexan and ...

Good luck !


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## brad72 (Jun 12, 2009)

Goldigger said:


> Come on Matt please talk x y and z, its the only language I understand


Jay, what about A & B axis when you convert the SX2 beast into a 5 axis milling machine


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## Goldigger (Nov 6, 2009)

brad72 said:


> Jay, what about A & B axis when you convert the SX2 beast into a 5 axis milling machine


Thats just crazy


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## mattthemuppet (Jul 16, 2004)

brad72 said:


> Jay, what about A & B axis when you convert the SX2 beast into a 5 axis milling machine


whaaat? Stop speaking in tongues will you!

I see the invidious (perfidious?) influence of the machining monkeys is seeping into this thread. I must stamp it out at once!


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## mattthemuppet (Jul 16, 2004)

TTGV said:


> computer heatsinks...


they're the best ones! You get added brownie points the older they are - the one I have in mind is from a PII (that's Pentium, not Phenom) slot heatsink. There's a risk that it'll make the light look like Dame Edna's glasses, but that's a risk I'm willing to take..


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## TTGV (Oct 31, 2008)

Whouaou !
What a night bird look ! Do you often cross this cyclist ?
The hairs make me say that you should have a go for a violet ano on your PII heatsinks !
Ah, and diamonds are the best for heat conduction....


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## brad72 (Jun 12, 2009)

mattthemuppet said:


> whaaat? Stop speaking in tongues will you!
> 
> I see the invidious (perfidious?) influence of the machining monkeys is seeping into this thread. I must stamp it out at once!


when words like invidious and perfidious are being used, it is time to get the hand tools out. Hand scrape the flats where the led dies sit and file the heatsink grooves. Must say though if my workshop was sitting at around -20º i would want to have a hack saw or file in my hand to get the blood pumping.

As for heatsinks, I found one from about 15-20 years ago. Perhaps I should donate it to the national trust or perhaps attach it to my mill made light to keep it real


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## mattthemuppet (Jul 16, 2004)

TTGV said:


> Whouaou !
> What a night bird look ! Do you often cross this cyclist ?
> The hairs make me say that you should have a go for a violet ano on your PII heatsinks !
> Ah, and diamonds are the best for heat conduction....


she/he rarely looks much better than that I'm afraid.

Only silver heatsinks - I once tried painting a light so the black heatsink and silver body didn't look so goofy and that was a time consuming mess.


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## mattthemuppet (Jul 16, 2004)

brad72 said:


> when words like invidious and perfidious are being used, it is time to get the hand tools out. Hand scrape the flats where the led dies sit and file the heatsink grooves. Must say though if my workshop was sitting at around -20º i would want to have a hack saw or file in my hand to get the blood pumping.
> 
> As for heatsinks, I found one from about 15-20 years ago. Perhaps I should donate it to the national trust or perhaps attach it to my mill made light to keep it real


it's the only way you can reconnect with the Real Man(Tm) within you Brad!

Also, having a slightly shonky looking light makes other riders, with their shop bought lights, a little less embarrassed that yours kicks their arses. IMO obviously


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## mattthemuppet (Jul 16, 2004)

and you all thought I was joking about the 6ft length of bear-beating tumultuous tubing?


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## mattthemuppet (Jul 16, 2004)

managed, just, to fit it in the vice and cut two lengths for the housing










cut a section out of each centre facing side to leave room for the driver and wire between the 2 LEDs










and JBwelded the 2 together overnight










now I know that JBweld sticks pretty well to wood  After cursing at it for a bit I got it all apart, it's all straight and the sled slots in perfectly.

now I need to drill and tap various holes, hack up a PII heatsink and figure out how to attach my Cateye spacer without skewering the driver. Off to a conference tomorrow, so no updates until next week..


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## Goldigger (Nov 6, 2009)

mattthemuppet said:


> and you all thought I was joking about the 6ft length of bear-beating tumultuous tubing?


6ft = 1828.8mm
That gives you room for 91 xml's on 20mm stars

Just stay off narrow single track with a 6ft wide light


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## mattthemuppet (Jul 16, 2004)

that should give me enough light I guess.

like you said, maneuverability would take a hit, plus passing people on even fireroads would be tricky!


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## jmitchell13 (Nov 20, 2005)

mattthemuppet said:


> None of this machining nonsense, XYsandwhatsits and all that jazz. I'm going to be rending a light with cold bare hands (cue Charlton Heston voice), some entirely inappropriate tools, a dash of incompetence and even my teeth if necessary.
> 
> So, after that intentionally inflammatory and attention grabbing title, can anyone guess what this simply awesome light will be made out of?


achesalot beat you to it...
http://forums.mtbr.com/showthread.php?t=272951


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## mattthemuppet (Jul 16, 2004)

beat me to what?

his (and Scar's) lights were the inspiration for my original helmet lamp last year, but their style is a pain to work with which is why I thought up this "sled-light" variation. This is my 1st double sled light after building 5 single sled lights. Thought people might be interested to see how it goes..


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## Goldigger (Nov 6, 2009)

I think we all are looking to deeply, well done Matt for making a 6ft long square tube.
How many rolls of foil did You have to melt down and extrude?


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## mattthemuppet (Jul 16, 2004)

Goldigger said:


> How many rolls of foil did You have to melt down and extrude?


none, though I did have to leave the wife at the shop so I could fit it in the car. She didn't say anything so I assume she was ok with it :yikes:


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## emu26 (Jun 23, 2008)

mattthemuppet said:


> none, though I did have to leave the wife at the shop so I could fit it in the car. She didn't say anything so I assume she was ok with it :yikes:


That reminded me of this super cheap auto ad from a few years back 





Matt, next time you JB weld like that stick a small piece of baking paper, you know the stuff the little lady cooks your cookies on, between the tube and the clamp. This stops the wood from sticking and the paper "should" peel of the JB weld dags that seep out. Also i have found the tubes stick together much better if you give the two facing sides a hit with coarse sand paper. The epoxy seems to key better that way.

Nice work


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## mattthemuppet (Jul 16, 2004)

thanks for the tips Emu, especially the baking paper. I scuffed up the mating surfaces with the dremel before hand as I've had plenty of experience of JBweld being poo. More progress next week, shouldn't take too long to finish up..

funny ad  I remember Supercheap, used to get alot of my car bits'n'pieces there.


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## mattthemuppet (Jul 16, 2004)

right, some more work done on Dame Edna. She aint pretty, but she's entertaining:









from the back









and underneath (oo-er missus)









heatsinks are from an old Pentium2 gel imaging PC that blew up at work when the power went out a while back. Drilling is superbly shoddy, but adds to that quintessential "made by a blind Englishman in a shed look" that hipsters get all wet over. The platform on the bottom is to add some more meat for the Cateye spacer screws to bite on - the housing tubing is thinner gauge than the sled ($20 for 6ft or $25 for 4ft, do you think I'm an idiot Mr. Homedepot?).

Now I need to drill some more holes - for the sled and spacer screws, plus the LED mounting screws. Tonight or tomorrow night, depending on how knackering the ride is tonight.


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## Vancbiker (May 25, 2005)

Hmmmm.... Might be a good time to buy stock in the JB Weld company 

I do like the large heat sink area. As long as you have a good thermal path from the LED to the housing those emitters should be happy.


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## mattthemuppet (Jul 16, 2004)

A little bit goes a long way  Seriously, since I started clamping parts together to JBWeld them, I've had to use hardly any of the stuff. Seems to help with the thermal transfer from housing to heatsink too.

The whole bottom of the sled will be in contact with the housing (cinched down with 4, possibly 6 screws, with thermal paste in between) so hopefully the contact will be ok. Seems to work well in the single LED sled lights I've made, so hopefully it'll be able to handle the full 20W. It's not as good as the unibody lights which have at least 1 less thermal junction, but mine is clearly going to be prettier!


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## mattthemuppet (Jul 16, 2004)

emu26 said:


> the little lady


if I called Ingrid that, she'd cut my nuts off. Seriously, she comes from the same region of Ecuador (Manabi) that Wayne Bobbit's wife came from (don't search from work, please). Even calling her The Wife gets me a dirty look.

oh, the baking paper trick worked a treat though, thanks


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## brad72 (Jun 12, 2009)

many have used a table say with carbide tipped blade for cutting fins. 

I use 125mm carbide tipped blades in angle grinders all the time for cutting alloy. Does a fantastic job. I also have a 125mm carbide blade mounted on an arbor for my mill. Just need to keep fingers away an they are far from forgiving.


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## brad72 (Jun 12, 2009)

Real men aren't scared of their wives. But like all real men we know what's good for us and by creating the illusion that ours wives are the boss we are able to get what we want and still get some action, if you get my drift. 

As for the light she's coming along nicely. Certainly looks like will handle the heat nicely and plenty of finned surface area. I look forward to seeing the finished product.


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## brad72 (Jun 12, 2009)

Goldigger said:


> Care to show us a pic Brad? I can only imagine its a slitting saw hence the arbor?


I'll put a pick up tomorrow Jay. More or less a slitting saw, just take 4mm cuts which is perfect for fin cutting, like trouties table saw. One of my workers has a 300mm saw blade on his mill. He did say he stands well back though


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## rschultz101 (Oct 5, 2009)

how do you cut your fins ?
without loosing fingers ?

still to poor, to get an X3 or even a ZX45 mill,...
anybody tried a plunge router ? or do you use a table-saw ?


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## Goldigger (Nov 6, 2009)

brad72 said:


> many have used a table say with carbide tipped blade for cutting fins.
> 
> I use 125mm carbide tipped blades in angle grinders all the time for cutting alloy. Does a fantastic job. I also have a 125mm carbide blade mounted on an arbor for my mill. Just need to keep fingers away an they are far from forgiving.


Care to show us a pic Brad? I can only imagine its a slitting saw hence the arbor?


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## find_bruce (May 8, 2011)

I want to say "looking good" but that doesn't seem quite right, nor does "not as ugly as you threatened".

How about "looking purposeful & practical"?


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## mattthemuppet (Jul 16, 2004)

brad72 said:


> many have used a table say with carbide tipped blade for cutting fins.
> 
> I use 125mm carbide tipped blades in angle grinders all the time for cutting alloy. Does a fantastic job. I also have a 125mm carbide blade mounted on an arbor for my mill. Just need to keep fingers away an they are far from forgiving.


I agree, that's a really neat way of cutting fins. However, I'm incredibly accident prone (plus I need all my fingers for work) and can't find locally the thicker gauge tubing that Troutie and Andy13 use. That's the trouble with buying 6ft of the bloody stuff, you're kind of stuck with it for the next 10 lights or so


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## mattthemuppet (Jul 16, 2004)

brad72 said:


> Real men aren't scared of their wives. But like all real men we know what's good for us and by creating the illusion that ours wives are the boss we are able to get what we want and still get some action, if you get my drift.
> 
> As for the light she's coming along nicely. Certainly looks like will handle the heat nicely and plenty of finned surface area. I look forward to seeing the finished product.


so very true. However, Manabitas (women from Manabi, Ecuador) are renowned for a) their firery tempers and b) punishing their husbands transgressions with a machete; flat side if you've only been a little bit naughty, sharp side if you've been very naughty. Pays to err on the side of caution IMO 

thanks for the comments. It'll certainly be a face only a father can love


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## mattthemuppet (Jul 16, 2004)

find_bruce said:


> I want to say "looking good" but that doesn't seem quite right, nor does "not as ugly as you threatened".
> 
> How about "looking purposeful & practical"?


thanks! the "not as ugly as you threatened" is quite a complement.

no progress planned until the weekend as I feel like I've been hit by a train after last night's ride and I plan on doing no exercise at all tonight


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## mattthemuppet (Jul 16, 2004)

okey doke, housing is now finished, with a bit of polish and elbow grease so it doesn't look _quite_ so ghetto



















cateye spacer, as usual










close ups of the sled










left to right: cable gland>remote wire>main switch










it's even bling on the inside 










thought that might help with heat transfer to the outer housing, though it's probably entirely unnecessary.

left to do:
add LEDs and wire it up (duh)
wire up 3S2P battery (double duh)
make remote switch from old taskled switch (hmm)


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## emu26 (Jun 23, 2008)

mattthemuppet said:


> right, some more work done on Dame Edna. She aint pretty, but she's entertaining:


Love the reasoning behind the name :thumbsup: I never thought I would say this but I honestly didn't ever think I'd see Dame Edna polish up so well

Light is looking really good but you know if you left it rough instead of polishing it you might have got away with half that amount of finning


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## Ofroad'bent (Jul 10, 2010)

Oh man, now we have to polish our sled lights? Matt, stop raising the bar.


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## mattthemuppet (Jul 16, 2004)

emu26 said:


> Love the reasoning behind the name :thumbsup: I never thought I would say this but I honestly didn't ever think I'd see Dame Edna polish up so well
> 
> Light is looking really good but you know if you left it rough instead of polishing it you might have got away with half that amount of finning


I'd love to rename it "The Black Mamba" a la Megamind, but Dame Edna's kind of stuck now..

I might have got away with less finning, but would it have looked as *awesome*? I think not


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## mattthemuppet (Jul 16, 2004)

Ofroad'bent said:


> Oh man, now we have to polish our sled lights?


not just on the outside either, but on the inside too! What, you want people to think we're amateurs?

this is the kind of polish I expect..


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## mattthemuppet (Jul 16, 2004)

any way, enough of those ridiculously overblinged Chinese cars, here's the sled all wired up









note to self, don't be a numbnuts and wire the driver in place BEFORE sticking it down with its thermal pad. What a PITA that was.

managed to hack up the optics holders (Laura RS in white, CXP RS in black) which fittingly were a piece of cake to locate over the LED (Laura) or a pain in the neck (CXP, had add a couple of layers of electricians tape). I don't care what the beam of the CXP RS looks like, no way am I using it again.









and underexposed









thankfully it all works - always the scariest moment in building a light!

now I have to find a pristine CD case to hack up into protective lens covers (CXP RS also has a big hole in it ) and build the remote.


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## Toaster79 (Apr 5, 2010)

Beautiful! That's some tidy wiring :thumbsup:


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## brad72 (Jun 12, 2009)

It's Alive.........well done mate. It's always a relief when light beams from those leds the first time it is powered up.


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## mattthemuppet (Jul 16, 2004)

Toaster79 said:


> Beautiful! That's some tidy wiring :thumbsup:


thanks! That's one reason why I like making these sled lights; they really make it easy to do tidy wiring as it's easy to get to everything. Oh, and I also chose the picture angle so you wouldn't see the shoddy stuff on the other side


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## mattthemuppet (Jul 16, 2004)

brad72 said:


> It's Alive.........well done mate. It's always a relief when light beams from those leds the first time it is powered up.


cheers  Scarily, it didn't light up the first time I connected the pack, only the STAT LED. I choose to ignore that fact, stuck the optic on and then tried again and it worked. Only explanation I can think of is that the battery came out of the fridge and needed time to warm up.


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## emu26 (Jun 23, 2008)

mattthemuppet said:


> cheers  Scarily, it didn't light up the first time I connected the pack, only the STAT LED. I choose to ignore that fact, stuck the optic on and then tried again and it worked. Only explanation I can think of is that the battery came out of the fridge and needed time to warm up.


I had that happen on the last light I built. Was rushing to get it finished before I went away for a 24hr event, ended up leaving it at home because I didn't have time to fix it. When I got home it worked :madman: Spent a bit of time going over it but found an intermittent short. Glad I did because it would certainly have played up on the trail. Go over everything again, just to be on the safe side.

Nice light, well done


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## mattthemuppet (Jul 16, 2004)

thanks, I'll do that.

Didn't get anything done last night, other than raid Ingrid's CD collection for unscratched cases.


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## mattthemuppet (Jul 16, 2004)

*finally, it is done*

as always, the last few steps are the hardest, but it's finally done.

Here's a breakdown of making the remote. Taking my hand of the bars to adjust the light setting is a pain, particularly on the rocky trails I ride, so when I saw Goldigger or Troutie (or someone else, my memory's crap) fashioning one out of an old Taskled momentary switch, I figured I'd have a go.

Body is made out of a alu offcut - I have loads of these left over









Switch is 5min epoxied to the underside









so that the switch pokes through the top









then, the magic ingredient - thermoplastic! Big thanks to Of'roadbent for the gift :thumbsup:

Starts hard









few minutes in my wife's coffee cup with some hot water and I shall call him Squishy









some frantic molding and shaping with my garden trowel and... ta da!

















some spare innertube and the eponymous 5min epoxy, plus an O-ring scrounged from the LBS:


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## mattthemuppet (Jul 16, 2004)

money *ahem* shot of Dame Edna (gah, that's a horrible thought)









and ze back


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## mattthemuppet (Jul 16, 2004)

now the battery

wired up









cables Sugru'd









first wrap of marine tape (from Home Depot, ~$13 I think)









several wraps later (I used 30in in total, out of 10ft)









then the velcro strap added and 3 coats of plastidip later









I just need to find a vacuum plug or something that fits over the balance port. The battery is 3S2P 4.8Ah, so should last 2 to 2 1/2h on full power.

Now I need to get some beam shots and take it into work to weigh it.


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## brad72 (Jun 12, 2009)

Nice work Mat :thumbsup:. Has she been out for the maiden voyage yet.


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## damian777 (Feb 7, 2007)

Looking good Matt!

I'm about to do the same thing (2 XML, regina sled build) and need some help on the wiring. I have done a quick sketch of how i think it goes, but would like some input from the seasoned light DIY builders.

I understand the H6Flex has a 1400mA minimium output. Is there a way i can wire it so each XML gets 700mA as this would be ideal for a low beam. Then medium could be 1400mA (half 2800mA) and high 1800mA (half 3600mA). Can i do this?

Cheers, D.


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## bobdotorg (Feb 8, 2011)

As I understand it, 1.4A is the minimum 'High' level - if you set it to 1.4A max, then there will be a few levels of brightness between 50mA and 1.4A:

I'm not yet worthy of posting a link, but here's the table from the tasked site:

Level	1400mA	2000mA	2800mA	3600mA	5000mA	5600mA	6600mA
L1	50mA	50mA	50mA	50mA	50mA	50mA	50mA
L2	116mA	116mA	220mA	220mA	250mA	307mA	505mA
L3	311mA	450mA	730mA	937mA	1105mA	1420mA	1620mA
L4	680mA	1020mA	1593mA	2022mA	2450mA	3000mA	3377mA
L5	1420mA	2022mA	2800mA	3610mA	5040mA	5640mA	6570mA

Also, the momentary switch and battery power each have two leads going to the driver - your diagram shows an on / off switch for the battery.


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## mattthemuppet (Jul 16, 2004)

brad72 said:


> Nice work Mat :thumbsup:. Has she been out for the maiden voyage yet.


not yet, although there are a lot of surprised/ blind rabbits in our back garden now. As long as we don't get a thunderstorm Thursday night I'll be taking it out for a spin then. I'll have to wait until it's properly dark so my mates are suitably impressed


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## mattthemuppet (Jul 16, 2004)

damian777 said:


> Looking good Matt!
> 
> I'm about to do the same thing (2 XML, regina sled build) and need some help on the wiring. I have done a quick sketch of how i think it goes, but would like some input from the seasoned light DIY builders.
> 
> ...


pretty much what bob ^ said - took me a few attempts to figure this out too. You set the max drive current (L5), then the driver uses a fixed table of current figures for L1>4, depending on the max current you selected. So if you select 3A for L5 (those figures above are for the older hipflex), L4 will be ~1.8A. If you want a dimmer medium mode, L3 will give ~800mA which would suit you perfectly.

I almost always use threemode L1>L4-L5, where clicking switches between L4 and L5, with a press to go back to L1 when I stop or need some light for getting something out of my pack. I might use L3 for medium, depends on how much I annoy my riding buddies with my new light


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## damian777 (Feb 7, 2007)

Ahhh, thanks guys. Makes sence now i read the guff on the H6Flex.

So the mom. switch gets wired to SWA and SWB on the driver? Battery to IN+ and IN- and LED's wired in series between LED+ and LED-?


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## bobdotorg (Feb 8, 2011)

damian777 said:


> Ahhh, thanks guys. Makes sence now i read the guff on the H6Flex.
> 
> So the mom. switch gets wired to SWA and SWB on the driver? Battery to IN+ and IN- and LED's wired in series between LED+ and LED-?


Looks correct. You'll need a 2S ( 8.4V) battery to run 2 XM-L in series.


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## damian777 (Feb 7, 2007)

Ah, I have a problem. What do i do when running 2 XML's from 18V?


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## bobdotorg (Feb 8, 2011)

damian777 said:


> Ah, I have a problem. What do i do when running 2 XML's from 18V?


Get two or three more XM-Ls and a pair of really dark sunglasses.


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## damian777 (Feb 7, 2007)

Sorry for the thread hijack Matt . . .

so, will the H6Flex driver not "buck" 18V down to the vf of the LED circuit?

I thought i had it sussed until today.


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## bobdotorg (Feb 8, 2011)

damian777 said:


> Sorry for the thread hijack Matt . . .
> 
> so, will the H6Flex driver not "buck" 18V down to the vf of the LED circuit?
> 
> I thought i had it sussed until today.


Yeah - hijacking is bad form, but anyone who sees the Dane Edna light as high art (myself included) won't be all that bent from a hijack. After this start a new thread, or do a quick search here and or on candlepower forums.

A buck driver will typically drop the voltage by one volt, so you'll be way overvolting 2 XM-Ls with an 18V batt. The magic of a buck convertor is how it efficiently steps down the current by turning full current on and off really quickly. Whoever invented the PWM deserves a Nobel Prize. Or at least a cookie.

Stepping down DC voltage from 18 to 8.4V will dissipate quite a bit of heat, so with an H6Flex (or any buck converter) get a lover V battery or add more diodes in series.


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## brad72 (Jun 12, 2009)

Like bobtogorg said, the h6flex driver can drive a single led from a 5s battery (21v fully charged) but all that extra voltage and current will be turned into heat in the driver and give pretty awfull efficiency. 

Like all buck drivers the greatest efficiency comes from using a battery pack as close to the led forward voltage (vf) + 1 volt overhead to keep the driver in regulation. For eg a 3s led light will run best from a 14.8 v pack, staying in regulation for the entire battery discharge curve.


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## MtbMacgyver (Jan 23, 2007)

brad72 said:


> Like bobtogorg said, the h6flex driver can drive a single led from a 5s battery (21v fully charged) but all that extra voltage and current will be turned into heat in the driver and give pretty awfull efficiency.


Your statement would be correct for a linear regulator, but is not entirely correct for a switching buck regulator. A buck regulator will have a slightly better efficiency when the battery voltage is close to the output voltage, and the efficiency will fall about 4-5% when you start dropping more than a couple of volts between the battery voltage and LED voltage, but that drop in efficiency stays about the same as you go to even higher voltages.

In general, a buck driver is always move efficient driving multiple LEDs vs a single LED. That's because a lot of the losses in a buck driver are fixed voltage losses such as diode losses. When you drive a single LED with a high differential input vs output voltage, the diode loss in the freewheel path starts to dominate and you don't get great efficiency. But that case is a double whammy because you're getting hit with a few % loss from the single LED case, and a few % loss from the high differential voltage.

Driving a single LED off a h6Flex isn't terribly efficient even when the differential voltage is fairly low and in most case you would be better off using an Lflex for a single LED. Driving 2 XMLs with a h6flex, even off a 21v battery, will be over 90% efficient which isn't bad.


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## bobdotorg (Feb 8, 2011)

MtbMacgyver said:


> Driving a single LED off a L6Flex isn't terribly efficient even when the differential voltage is fairly low and in most case you would be better off using an Lflex for a single LED. Driving 2 XMLs with a h6flex, even off a 21v battery, will be over 90% efficient which isn't bad.


Really? I'm knowingly continuing to participate in hijacking the H.M.S. Dame Edna thread, but I was under the distinct impression that an H6Flex would spew heat if one tried to inject a 21V battery into two, three point something volt Vf diodes.

My EE exposure is decades old, but (I hope) the fundamentals are true. If I'm wrong, please be brutal in pointing out my error.

Having said that, it's first light here in L.A., so I'm off for a Runyon Canyon loop.


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## MtbMacgyver (Jan 23, 2007)

bobdotorg said:


> Really? I'm knowingly continuing to participate in hijacking the H.M.S. Dame Edna thread, but I was under the distinct impression that an H6Flex would spew heat if one tried to inject a 21V battery into two, three point something volt Vf diodes.
> 
> My EE exposure is decades old, but (I hope) the fundamentals are true. If I'm wrong, please be brutal in pointing out my error.
> 
> Having said that, it's first light here in L.A., so I'm off for a Runyon Canyon loop.


Sound like you think the h6flex is a linear regulator like the lflex, in which case your statement would be correct. The h6flex is a switching regulator.


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## bobdotorg (Feb 8, 2011)

MtbMacgyver said:


> Sound like you think the h6flex is a linear regulator like the lflex, in which case your statement would be correct. The h6flex is a switching regulator.


OK - I'm highly intelligent, but easily confused.

And this is my tenth post mofos. So now I can post links.

But I'm curious, slightly confused, and too lazy to look up the answer before hopping in the shower and taking a SoCal June Gloom nap.

Is the H6Flex linear, or switching, or both? My understanding is that it drops V by 1, no matter what Vin. It can vary A via PWM, but Vout is always about one volt less than Vin.


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## mattthemuppet (Jul 16, 2004)

no worries on the thread hijack 

as others above have said, the h6flex (and b2flex) are buck or step down switching regulators, so the battery voltage has to be LED voltage string + 1v for overhead, eg. 2S LEDs need *minimum* 3S battery, 3S needs 4S min. Battery voltage maximum is 21V IIRC for the h6flex. Now, if you ran a 2S LED string with a 2S li-ion pack, you'd still be fine, but the battery would go out of regulation about halfway through the discharge curve. This means that the LED would be direct driven (no voltage adjustment by the driver) and as it discharges further the LED would dim (as battery voltage dips below the LED string voltage).

Now, linear regulators are essentially fancy resistors that burn of the difference between Vin and Vf as heat - so 1 LED with 1 li-ion is fine, 1 LED with 2 li-ion is very bad (bigger the difference, the greater the heat).

Then there are boost regulators, which increase the voltage from the battery to the voltage of the LED string, so that a 2S battery can drive a 3S LED string - the maxflex is a good example of this.

tricky to get your head around, but in summary:

Buck: battery cell count = LED number + 1
Linear: battery cell count = LED number (no >2)
Boost: battery cell count = LED number - 1


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## bobdotorg (Feb 8, 2011)

mattthemuppet said:


> no worries on the thread hijack
> {SNiP]
> tricky to get your head around, but in summary:
> 
> ...


I'm going to guess that that last line was meant to be 'boost'


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## mattthemuppet (Jul 16, 2004)

crap. thanks for keeping me honest


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## bobdotorg (Feb 8, 2011)

mattthemuppet said:


> crap. thanks for keeping me honest


Anyone who spends dozens of hours methodically grasping and and then trimming and polishing Dame Edna's unnecessary bits has no need to be honest. Deeds speak louder than words.

For those about to light the hillside, we salute you.

(I have _got_ to stop posting after staying up all night. Goddam grad school encourages bad posting habits.)


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## damian777 (Feb 7, 2007)

Thanks for your input fellas.

So in summary:

vf of 2 XML in series = 6.7V 
+ 1V for overhead = 7.7V
Therefor *minimum* voltage in H6Flex = 7.7V

so, 18V into the H6Flex is ok but efficiency will not be quite as good.

Hijacking over :thumbsup:


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## mattthemuppet (Jul 16, 2004)

damian777 said:


> Thanks for your input fellas.
> 
> Therefor *minimum* voltage in H6Flex = 7.7V
> 
> ...


that's right. So a 3S pack will always be in regulation (9V at full discharge) whereas a 2S pack will go out of regulation under 7.7V (6V at full discharge).

As mtbmcguyver said far more eruditely above, I don't think 18V for a twin LED light will be a problem, you'll just be carrying around a far bigger and heavier battery than you need to.


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## mattthemuppet (Jul 16, 2004)

some beamshots, sadly on wet grass (hey, at least it wasn't _in_ the rain)

see all of them here for comparison. Just Dame Edna:
















CXP-RS alone








Laura-RS alone









as you can imagine, I'm pretty pleased 

all grass (wet, sorry) pics were AWB, ISO200, 2s exposure. All side-of-garage pics were AWB, everything else auto


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## find_bruce (May 8, 2011)

mattthemuppet on another thread said:


> My new light has a cobbled together remote and it's awesome. You can even do "helmet slap" remotes for helmet lights.


Hey Matt, I can now picture you wearing Dame Edna, while you ride along slapping the side of your head.

I am hoping you annodise Dame Edna in an appropriate colour, say blue rinse or purple & add some diamantes. Don't forget to post a head slapping video


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## mattthemuppet (Jul 16, 2004)

ha ha, yeah, the helmet slapping would probably be me trying to change light modes before going over the handlebars onto some rocks. No way I would wear Dame Edna on my head though, far too heavy.

given the raised eyebrows I get at what I do in the garage already, I don't think anodising would be that great an idea. That and the fact that I'm _excessively_ accident prone..


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## mattthemuppet (Jul 16, 2004)

Just to give an update, I took Dame Edna out for her first ride last Thursday. 

Wow, a simply insane amount of light, so much so that there didn't seem to be a huge difference between L4 (1.7A?) and L5 (3A). Beautiful beam pattern too, very smooth, just the right amount of side spill and a nicely graduated hotspot. Having it on the bars made an enormous difference to my riding as our trails are incredibly rocky and I always struggled to pick out a good line through the rocks with just a helmet light. Now they all had enormous black shadows, so I couldn't miss them. Didn't go over the bars once!

No issue with heat, though I ran it at L4 most of the time (though I'm thinking of dropping it to L3, just so I can see the difference in levels), cable was cool, didn't even dent the battery pack's capacity. It also paired well with with my helmet light (XP-G R5 and XM-L T6 with Reginas @1.2A, so ~750Lm) although it did make it seem a bit dim in comparison. I might have to replace that XP-G with an XM-L and bump the power to 1.5A 

Next build is an Easy2LED light (the housing won from the recent poll) for a friend.


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