XM-L Sled Light- Mattthemuppet-style.
I thought I'd start a new thread, as Matt's old thread was about a single XP-G light.
I've got a light in progress using Matt's housing and sled idea.
All I'm waiting for now are the electronics.
The top row shows:
-Lexan outer cover- to be siliconed in place.
-1" tubing main housing, still to be cut to length once I measure final electronics.
-L-shaped bracket, which will get 3M Dual-lock on the bottom and velcro over the top. The light should mount well on a helmet and tilt nicely with this. It may also sink some heat.
-End cap with obligatory fins.
Bottom row shows:
-Regina reflector, to be cut down (Also an 18mm DealExtreme reflector on the way to try)
-Mini-Sled cut from 1" tubing- it's a nice tight fit in the back of the housing.
-Waterproof momentary switch
-Magicshine cable with cable gland stolen from old cell phone charger.
- XM-L emitter on a 20mm board, which goes on the front of the sled. Probably take forever from Dx, but they say they've packed them for shipping.
- L-Flex, which goes on the back of the sled front, behind the XM-L. - probably take 4 days from Taskled.
- Protected batteries and charger - already have 1S2P holders
The end cap will be JB welded to the back of the sled, to allow an O-ring seal between sled and housing for easy 1-screw disassembly.
Matt was kind enough to send some heat sink too, which I may mount later if needed.
I should have parts for more lights after this, once I decide whether I prefer the XM-L or a Quazzle triple.
I think you will have thermal bottleneck that limits the light output. If I understood you correctly you plan to mount LED on one side and driver on other side of 1.5mm aluminium profile that is mounted to the rectangular body that works as heatsink. All the generated heat must be transferred to the body via narrow 1.5mm bridge. Even if you cool the body of the light, the LED and driver will still be at elevated temperatures. If the temperature is too high, Lflex will dim the light to save the driver and LED.
Thicker sled might help. Or separate sled for driver.
Thanks, I've been wondering about that. I'm thinking of an L-bracket inside the sled for the L-flex if it turns out to be a thermal problem, as long as there's enough room.
Originally Posted by arnea
OK, L-bracket made up for the L-flex, which will be mounted with thermal tape to the bottom of the sled and screwed together. Now, should it be thermally coupled with the front of the sled as well, or should I leave a small space between the sled front/XM-L and the L-bracket/L-flex?
I'd leave a gap or stuff something non conductive down there (rubber washer, electrician's tape) to give it a bit of support.
I've decided to use 1.250" tubing, 1" ID. 1/8" walls w/ exterior fins cut w/ a table saw. That, along w/ an "accessory wing" for the lflex, should make the heat dissipation a non-issue. The sled and accessory wing will use 1/16" square tubing. The larger exteriror housing should also make the build much easier. The housing should be approximately 43.5mm X 31.75mm. I have everything but the driver and xm-l but should get them both this week from George and Cutter.
A progress report of sorts- I JB welded the back plate on the sled, and did a trial assembly with an o-ring between the back plate and body.
The tension required to compress the O-ring was enough to partially de-bond the back plate.
The whole idea was to allow for a tight seal with only 1 screw, and easy dis-assembly.
I was hoping not to have a tightly bonded sled that's a b!tch to remove for tinkering.
ODTexas's design is much simpler, potted up with JBweld, but it's never coming off.
I think I'll have to use black Gasket Former silicone instead of an o-ring between back cap and body, which can be a bit messier. I'll need to lubricate the body so the back plate/sled is easily removable.
So far, I'm not sure the back plate idea is worth the trouble. It was a fair bit of fiddling to prepare and align, with holes and fins, even if it does look cool.
The secondary bracket for the L-flex should be fine in the sled.
It's looking like a build with a Quazzle triple and no back plate might be less work, if you're looking for a quick and simple build.
Could you use a plastic end cap to enclose the end?
You would have to relocate the switch to the top maybe, but the power wire could still feed through the end cap.
just sealing the back with a thin bead of silicone just inside the lip is really easy (push in, wipe off excess, all done) and it comes apart easily too. Then all you have to do is peel off the old silicone and add a new bead. I've done several like that and taken a couple apart, and it hasn't been a hassle at all.
Originally Posted by Ofroad'bent
Last edited by mattthemuppet; 02-25-2011 at 07:12 AM.
The main point of Matt's sled design is that all the electronics are on the sled. An end cap and a relocated switch would work, but would need a different design. I am also counting on some heat sinking from the back.
Originally Posted by KBARK
I think the sled would be easier to make without the back cap.
Woo-hoo, got the L-Flex. It fits behind the front of the sled OK, but since I added a secondary bracket to mount the L-Flex within the sled I will need to grind a deep groove almost all the way through the base of the bracket to allow it to fit. I'll get some pics once it's mounted.
I got the battery case wired up too.
My XM-L and stuff should be here soon- DX says it shipped last week.
I am using the larger aluminum for the housing which has an ID of 1" and I still don't see how I am going to cram it all in w/ the interior of the switch and all. It all fits fine, in theory and on paper.....There's just not alot of room for error. I'm really glad I am not using the smaller tubing!
Here's my modified L-flex bracket, which will sit within the sled with the base facing backwards. It will attach with the same screw that holds the sled to the body.
Originally Posted by Andy13
There's a cut-out for the L-flex, and one for the cable gland too. Things will be a bit tight but it should all fit
I think using 1.25" OD square tubing to make a longer sled inside the same 1" OD housing would give more room to allow a bracket to face forwards, and then no mod will be needed to fit the L-flex. Picture a 2-seater sled.
Last edited by Ofroad'bent; 03-03-2011 at 07:38 AM.
I was able to shave off some of the sides of my lflex in order to fit it in my square tube housing. I tested it and it still seemed to work fine.
I'm still waiting on a 2600mah battery to be delivered so that I can finish it up.
looking good I take it that, even though you said you're waiting for the lflex, the fact that you have one wired up means you're waiting for the XM-L? Looks like it all fits in there surprisingly well, if a bit fiddly.
BTW, if you're ever in need of a good strain relief/ cable gland material, Sugru is fantastic. It's some kind of magical silicone rubber blend that's hard but flexible. I used it on all 4 of my new XP-G lights and it's been holding up well on mine.
looking forward to the finished product!
Originally Posted by mattthemuppet
shows how to make a similar product for a LOT less $
Basically acetic curing caulking silicone and corn starch. Just helped my son with a science project and we used it to make some casts from home made molds. The stuff works great - just make sure you squeeze out any air pockets - but that's typical of any similar potting type compound.
cool, thanks for the tip George! I have five packets left (1 packet did 4 cables plus one kitty face), but when it runs out I'll definitely try this. I wonder if this could be used to encase and protect LiPo batteries?
I also make a lot of silicone molds for a table top game I play, which is pretty damn price ($30/lb), be interesting to try this for making molds too.
Thanks, fixed it - I have the l-flex but not the XM-L LED.
Originally Posted by mattthemuppet
Last edited by Ofroad'bent; 03-05-2011 at 03:37 AM.
georges80, thanks so much for the tip on the Oogoo - Sugru substitute. That deserves a sticky all by itself.
The study du jour: can one's reputation be artificially inflated by simply putting a request for rep in one's sig?
Interesting. Dentists use all kinds of silicone putty and pastes of different consistencies for super-accurate impressions. They are 2-part ones that set in 3-6 minutes. They do tend to come only in brilliant colours. I have a ton of pale blue 2-part putty that expired years ago but still works.
Originally Posted by georges80
looks really tidy, I'm impressed! Glad DX came through for you, takes a fair bit of forethought and patience to deal with them.
has the thermal protection tripped at 3A while riding, even slowly? That's the most useful test for me as most of our high powered lights will trip eventually in still air.
if you want to remove weight, you can always trim the bracket too.
oh, and another thought - this would be ideal for a remote switch on the side of the helmet, something using an old Taskled switch and some sugru, for example..
Thanks, Matt. I just got the light assembled last night. The trails are covered in ice right now, so no riding for a while. I set the thermal trip to 70C, so we'll see. I may need to dial it back to 2.5A max. The light gets warm, but maybe that's the heat radiating out from the thin aluminum more than with a heavier light.
Originally Posted by mattthemuppet
The bracket's oversized because I am hoping it will act as a further heatsink. Rather than fins, I thought a wide but thin bracket would add a couple of square inches, so I didn't even round off the bit that sticks up.