JC did you see the aquarium torture test? I'm now thinking about just mounting the LEDs on some 1" angle aluminum and running them unprotected under my soffit.
JC did you see the aquarium torture test? I'm now thinking about just mounting the LEDs on some 1" angle aluminum and running them unprotected under my soffit.
away from angles, channelsdo exist. I'll see if I can conjure up some pictures this weekend
I think from a purely experimental standpoint wrapping duct tape on the side opening of the channel should be more than adequate to keep water from flowing into the assembly from the top, though mounting ability might need some looking into. Granted I can drill holes on the side and mount it in that manner, but having a nail or a lag screw head stuck out within the emitter's viewing angle may introduce unwanted artifacts
Kapton tape is nice, but I'll check for local availability of teflon washers before I go about testing the waters in DX or KD.
Last edited by Illum; 11-29-2009 at 12:04 PM.
The dome did come off when cleaning was attempted and look at how filthy and poor the light quality must have been at the end. Granted, it's likely out of and away from water an LED won't get that bad that fast, if ever, but it is reasonable to think they could need cleaned one or more times within their viable lifespan. I've torn domes off XR-E's just barely wiping around the dome.
From a construction/materials cost and design/build time perspective I accept running bare LEDs could be desirable to some people, it is up to each to decide for themselves. I would want something that resists damage if someone not acquainted with how fragile the dome is, tried to clean it.
Last edited by J_C; 11-19-2009 at 03:00 PM.
the LED enclosures are underway, for now I'm surprised no enclosures exist for the xitanium, either too big or too small
Its thanksgiving week/Exam review week so I had made no progress on the build. the power system is under way but water proofing the concept still proved to be an obstacle. I used paper twoel wadding stuffed to sides of holes around the experimental boxes then sprayed water all around after the glue is dry. No go, there were no stock on three gang exterior junction boxes [dunno if they even exist] and the three gang interior junction boxes had so much holes on it its impossible to waterproof for outdoor use
If you haven't bought the Xitaniums yet, another option might be to use an exterior 12V lighting power supply (Malibu ...) and then use individual 12V drivers at each LED. You should be able to drive a lot of leds off one power supply. These DX drivers have been well reviewed and cost under $2 when you buy more than 3.
MR16 1*3W 320~350mA Constant Current Regulated LED Driver (8~40V Input)Price: $2.40
Given the location of the light is primarily outdoors, designing seperate enclosures for drivers for each LED [6 on one string, 12 total] sounds like an addition expenditure I can afford to do without
All this L and U stuff here started getting confusing, as some people can't understand the figurative speech. L is for aluminum angles, U is for Aluminum Channels.
Here’s my “workbench” lit by 3 LuxVs on the front driven at 700ma, a central overhead “75W” CFL and flanked by three RX1H Luxeon stars [350ma] above my LM317 voltage regulated power supply.
I set up the central bus that connects the two Xitaniums to a central junction that plugs in into the wall. I found an AC pull switch for a florescent fixture that was thrown out and decided to use that for the main switch.
I resized pictures at 640x480 because when I previewed this post sized at 800x600 was way too slow even of my broadband
the enclosure shown here is a Radioshack 4" x 2" x 1"
It cannot be an easier build, find a 6 row bus bar, inter tie 3 channels to each, 1 for power the other two for the two xitaniums, drill a hole where the pull switch will sit, mark the holes on the side to drill out for power chords, put it together with a wiring diagram
It will be mounted upside down from the first picture.
I found a box big enough to hold the xitanium, but from the looks of it, I could fit TWO xitaniums and then some. 0.o
Okay, now for the LED modules...
Grab a bar of 1-1/2” x 1/16” Aluminum Angle and start marking the pieces. Each 12” partition will suffice the thermal output of two CREE XREs at 700ma.
Cut the Angles to spec, the first partition on the picture from the top is more another project, driven at 350ma. It is what you in the first picture of the post where the luxeons are shining from
With the placements now marked and stamped, it’s chucked and drilled, bore at 1/8” for both mounting and wiring
With the holes bored we can now get to work epoxying the LEDs down
Now that its epoxied, we can go about soldering in the connecting wires, I’m using 22 Gauge AWG for the long distance ahead
With All three modules connected between LEDs, I connected all three modules together with some scrapped 24 gauge wire to do an overnight test run and determine what will go wrong before I go about installing it outdoors
In my room, pre-test
The output is incredible, no words can I describe how bright my room is at the moment, it was previously lit by 3 fenix lightbars at max, and this blew that out of the water!
I’m really looking forward to putting it outside and see it from the outdoors perspective
There's some minor delays until it can be mounted to the porch
for now, there's some weatherproofing to do
Had some medical grade tubing to spare, decided to use that to link up the wires
I decided to tie everything in the negative line and leaving the positive wire in a straight run, but as it turned out to run the tubing I had to cut them open and resplice/solder them
I dropped some elmer's glue where the wires perforate to the other end. I'm out of candles or else melted wax will do
For the central junction box, there's tubing for that as well the tubes from the connecting module will be taped to the extensions being a little offset for proper strain relief and allow a little "give" on the tube channel
I have already set up the mount placements, once this is all done the third and fourth module will be installed in a similar manner, hung up, and energized
You're not going to make the switch pull chain a piece of fiber optic cable lit by an internal blue led?
Looks good so far, am anxious to see the finished result.
As for the LED moisture barrier, I've finished cutting pieces of cellophane film and stretching them over the LED dome. Lay on 1-2 layers and pushed down to stretch over the LED yielded much needed rain protection without artifacts. Its not waterproof, but droplets of water from the gutter and mist will take sometime to get near the LED
If I must "waterproof" it, I suppose a square cut film flanked by tape on all four sides could be an option
They don't look too fancy looking at it but at night I doubt anyone would look for it.
The best "caps" I've found thus far is the left over plastic carton from radioshack's button cell cartons
Last edited by Illum; 11-27-2009 at 11:28 PM.
Since dad is planning sometime next year to modify the gutters, I designed everything to fit together with breakouts as well as mounting them to the beams the way one would hang a picture. All I need is a Philips head and I can take apart everything and put them in rudimentary piles
Continued from yesterday
the last of the soldering
As mentioned yesterday, I was pondering the use of cellophane wrap.
Its remarkable ability to cling to the aluminum and acting as one single layer of plastic when overlapped had me optimistic...until
The LED still worked, but that made me change my mind about using it as a moisture barrier, and I went with the cheapest and readily available supply in my inventory room: tape
I used boxing tape to create a weather guard awhile allowing some air convection to access the LED. To prevent the tape from yanking the dome off, here's what I did
cut a 1" thick piece of tape and lay it sticky side up
Cut a ~3" thick piece of tape and adhere it with the 1" at the middle
Place the "assembly" over the LED, and only allow the sticky parts to contact aluminum
the heatsink design will not reach the temperature sufficient to melt the tape into a sticky mess, if it does, at minimum none of it will touch the LED
For the sheared dome LED, I decided to tape it down and seal it
More pics will continue on the next post, for now my computer is still resizing them
The central junction box had me working for a couple hours. In design I specified 18 gauge and had simulated the wiring using spare wires..but when dad came in and said we have weather resistant wires in the garage I went with it, but as I started splicing I realized it wasn't such a good decision
change in specs
Stranded copper -> Solid copper
18 Gauge [AWG] -> 15 Gauge [AWG]
So I had to open up the holes a little bigger, and force the wires around to get it to fit
What I began with
the new wire couldn't fit the silicone tubes, so that plan was scrubbed
Spliced, I bent the ground wire down and crimped it backwards into the wire. this made a bump on the wire surface that, when forced into the enclosure, stays in the enclosure. Should one assembly fall from the mounting place, it'll act as a strain relief from directly pulling on the wires in the breakout
The jumpers on the terminal block is 18 AWG, the copper alone on this new wire is the same thickness as the 18AWG with the insulator on
Not wanting to put new holes where I expect water to hit, I taped the terminal block to the enclosure
I couldn't wedge the wire beside the screw so I had to take the screw out and stick it in. It cross threaded a couple times but it went in.
Solder the switch on, my 25W iron took awhile to heat the new wire up, I think I need a new tip or a retinning
As mentioned before I want the parts to be removable, so I sticky taped the enclosure to an angle, taped it down for extra hold. this tape is not the 3M variety and you can't tear it apart with giving it a little cut to start
After the connections were tested and function, the unit is sealed and hung. Here we are, the wire leading off to the right is to the xitanium, the one leading to the overhang is to the receptacle, I decided not to fuse the circuit, the xitanium draws 200ma max, I don't know if 125V .25A fuses exist
Wiring the xitanium box is in the next post
Last edited by Illum; 11-29-2009 at 12:17 PM.
The downside of that approach is that when it gets moisture in there, it can't get out.
I plan to give some a coat of epoxy. There's a big thread on here speculating about it. It didn't look like there was any proof about it working or not.
that's true that's something I'm still trying to figure out. I wonder if I leave it on 24/7 would it retain moisture?
The enclosure with the xitanium, what I like about the enclosure is not that its big enough to stuff in a couple xitaniums...but that's certainly a good thing to have.
Note how close the length is of the xitanium with the length between the standoffs, its a snug fit
I've added a 4 block terminal bar here that will receive incoming AC and departing DC, this allows me to isolate the AC input or isolate the DC end [good for breakdowns]. I changed the configuration after the picture, the block diagram from top to bottom is Line, Neutral, Positive, Negative
This also allows me to swap out xitaniums [if 700ma was too strong and 350ma is ideal] without having to manipulate the connections, just unscrew the AC end and DC end then do anything on the floor instead of standing up and resting my head on the gutter
Last edited by Illum; 11-28-2009 at 04:51 PM.
Results, it was better than I expected, I did not want the wall to be screaming bright but I was afraid it might be too dim. It came out balanced pretty well, but I might have to move some of the hanging plants for the added effect
Dusk, Since the screened porch is flanked by a wall of plants, there's little to no need to zip up the curtains, the daylight that goes in the windows saved us alot of money for lighting
The picture is dimmer than it appears, NW had the best color rendition over WW and CW. But it illuminated the ground, the wall, and vegetation with adequate intensity. Since all fixtures are movable, I might adjust the placements in the future, for now I'm done
Last edited by Illum; 11-29-2009 at 12:18 PM.
The problem with clear tape over the emitters is you'll eventually get moisture / condensation in there, and it will have a hard time going anywhere then. This might actually cause the emitters to fall apart faster.
For general protection, a cheap optic over the emitter along with a generous spread of expoxy around the base works good. Acrylic and hardened epoxy are among the toughest materials in a harsh environment.
I hate to give away ideas, but one thing I'm working on you might want to try for outside duties is this: get a couple pieces of 3/4 inch wood strips from a hobby or home supply store. Cut the strips the length of your alu bar, and glue them to either side of the emitters along the alu bar length. Now, get a cut piece of clear plexi, or, acrylic diffuser from a home supply store meant for fluorescent ceiling lights and attach it to the wood strips. This way your LEDs are inside a nice housing. I use this method for my reef tank light because bare LEDs don't last long under the salt splash. I guarantee it will take plenty of abuse outdoors.
Illlum, well done.
Given the success of this project came the failure of meeting to budget and deadlines. I overshot this by two weekends so Part B has been placed on hold indefinitely. I'll be away on a family vacation by the 16th.
I understand epoxy might be the best answer for everything, but I failed to understand it prior to buying stars. I could've used emitters
where potting with epoxy would have been very easy and will save me some $10.
I have been looking into optics, specifically
But I'm not sure whether or not that has the effect I'm looking for
I have a couple of these: http://ledsupply.com/247-10-lens.php
Bought for the bike light project, which works well for a headlight but not exactly what I'm looking for in this build
Whenever people speak of epoxy in relation with LEDs I think of stuff like Norland 61...and that stuff isn't cheap
This porch is like a black hole at night, with dark walls lined with dark vegetation. I mounted the bars on the center of the 2x6 beam to faciliate light downwards but not outwards where it would be distract anyone sitting on the deck. While lighting up the vegetation I also wanted light to light the wall as far up as possible, which was one of the main reasons I mounted the LEDs on the bottom of an aluminum angle rather than on the inside of an aluminum channel.
If I wanted to make a fish tank light I'd use a 3/4"-1/2" wide 1/16" thick channel where LED stars can easy "drop" into the channel with a window and end caps fitted over it. Depending on mounting methods one could buy some long finned heatsinks made for passive cooling and epoxy them to the top or side of the channel
I hear what your saying though. And something similar was designed in the past as well. It concerns the use of an aluminum gutter and very amateurish metal fabrication. I apologize for the messy and ill-proportional picture drawn in mspaint. If my drafting license didn't expire I'd come up with a technical drawing
What I came down with is:
- If I was to seal it up using some medium or method I have not yet devised, moisture will find its way into it and every time the light is turns off it'll condense to water and stay in the medium and collect on the lowest point, where happens to be the LED dome in the current setup.
- If I left it open for air convection flow, then the LED will contact moisture very easily and may perish through electrolytic corrosion and sequential oxidation. But it is also self drying as each time the fixture is turned on the heat produced from the LED will heat the metal to 85-90F and it will slowly "cook away" the water condensate.
- If I did nothing about it by spring the monsoon season will trip a couple breakers, fry a couple LEDs, and laugh at me in the face for building such an ill-protected contraption in the first place
- If I built a sophisticated air cooled/humidity controlled environment for them where I can store my stamps, cameras, and photos in its air reservoir cell I will have overshot my budget so many times over that it'll be cost effective for me to buy low dome outdoor HIDs and toss the whole LED assembly in the trash
So, my proposal for now, until I can achieve the 5th alternative, I've wrapped all the LEDs in tape [not sticking to the dome except the failed one] but left the sides open and leave them on running 24/7, keeping the metal warm and the LEDs dry.
Its going to be the final exam season for the next two weeks so I don't have time this year to go back and do any substantial modification. However, I can still sketch up new ideas for it.
Last edited by Illum; 11-29-2009 at 12:03 PM.
you might try something like "Electro-Seal" it comes in a spray can and goes on like a thick contact cement but dries quickly and is quite rubbery so can handle expansion, it says it will work even if the item is going to be used under water and while it looks like it would work well i haven't tried dunking my cell phone yet to see
i have used it on some of my DMX Decoder boards that were to be outside somewhat unprotected and it seems like really good stuff, it ranges from $8-$15/can so it is not expensive. i have even sprayed the circuit boards including the front screen "not the main one tho" on my cell phone to help make it more water/shock proof.
i would still tape off the center of the dome as it is clear but not as clear as glass and you don't want to loose any light output.
it would be a lot easier than making a box or cover for them and you wouldn't have to worry about condensation or moisture buildup:-)
they also make a high temp version but i have not tried it nor do i think you would need it for this
well, its still going strong.
We had a couple torrential downpours so far with no issues. Instead of turning it on and off I decided I'd leave it running 24/7. Even when its 40 something out the heatsinks are quite warm throughout the night.
No condensation has yet to be observed to accumulate under the tape seal.
However, I have one emerging issue....one of the CFLs from the wall fixture burn out prematurely, upon inspection the globe is half filled with water possibly resulting from the rainwater trickling down the power line I installed adjacent to it
By dad's request I might go about modifying the wiring and possibly create a channel to duct the rainwater away. For now I'm stuck on another project...this time for an astronomer friend who needed to illuminate a remote 10ft by 10ft work deck in red LEDs...preferrably dimmable and 12V input. I'm currently tapping out the bugs of running close to 300 Piranha red LEDs on a single Luxdrive boostpuck.
There is some blue RTV compound you can get at auto parts stores- I used to use it to pot CPUs back when the 'peltier' craze was going on- you could coat the back of a Slocket adapter and put neoprene around it to help insulate. No issues booting, which meant no conductivity- and no water intrusion over several thermal cycles.
Anyway- what I was getting at was I really like the ideas. I wonder if theres an easy way to bore out the inside of the copper caps (or just go to 1" copper) to try and smooth out the surface. Wouldn't be but two seconds for someone with a functional lathe or end mill (do they make 3/4" end mill bits? Hrmm...)
You could easily pot a piece of lexan or glass (no plexi!) over the end of the cap, and attached to the aluminum bracket you'd be in pretty good shape for conducting the heat away.
Very interesting project.
Since its completion back in late November of 2009 the assembly has been on every night from sunset to sunrise...on occiasion left on to dry out the metal if a strorm passed at night.
To date it has ran a total of 220days, assuming 12 hours/day the assembly has operated without an issue from any part for over 2600 hours
The house had new windows put in as the old ones were some 30 years old and the insulation is essentially non-insulating. The new ones has dual reflection coatings [two layers of glass, argon filled] and these LEDs provided just enough light to create a one way privacy window to the master bedroom at night.
Mom noticed that the plants under the LEDs seem to grow better, despite the lack of evidence that such LEDs has what it takes to stimulate chlorophyll the plants do see to like it, it changed mom's perspective on residential LEDs and so it did I.
There were issues though regarding the LEDs attracting bugs, being lukewarm all the time it provided a haven for spiders and flies who likes to congregate between the tape shield I placed on the emitters...it takes one bug to dehydrate and die at the entrance to cause the entire assembly to die under it. Out of 6 LEDs 2 had this fate, I had to cut it open and rub down the LED to allow light to come out of them.
Since the intensity hasn't appeared to dim after over 2600 hours, and that the heatsink is hardly warm, I'm thinking of going up one tier higher and use a Xitanium off-line 1000ma driver. Last I recall CREE 7090 XRE Datasheet indicated the absolute maximum foward current as 1000ma, but the 25W Xitanium's 1050ma...I'm not sure if I'm willing to lose $50 worth of LEDs for kicks.
Last edited by Illum; 08-02-2010 at 01:42 PM.
Well, a year and a half down the road running 24/7, over half of the LEDs in one string failed [close circuit] and the other half the xitanium went bottoms up.
The XREs were so fogged up by the humidity and the resultant corrosion that they were actually becoming discernably dimmer.
the dead Xitanium 700 on top, notice two resistors are missing, a transistor blew up, and several diodes have failed. The cause was traced to a water leak and a spider egg sack that was nested [of all places] under the output connectors.
Given the condition of the xitanium [melted plastic, a gut wrenching smell of burnt electronics] I was blessed to know the house didn't catch fire.
The existing system has been decomissioned, a future system shall employ a dusk to dawn switch and a modular system operating on a 12V rail. This way failed modules can be removed and replaced without shutting down the entire system. LEDs will be sealed with dielectric spray and be configured to increase the heatsink temperature as high as safely possible [to ward off the critters that likes to sleep on it, such as frogs]. 12V as opposed to other voltages would allow me to use different LEDs up and down the stream, plus the ease of using tri-XPG stars vis current limiting resistor.
I wanted to create waterproof modules that have integrated buckpucks, but thermal dissipation has long been the main obstacle. I could use die-cast aluminum enclosures, with a hole opened for the LEDs, but the material cost of that idea easily overrules its benefits.
I'm not familiar with the moisture resistance of the buckpucks. Would it be feasible to epoxy it to some aluminum extrusion and then spray it with conformal coat to provide the needed moisture resistance? I'm assuming that the proper aluminum extrusion, such as C channel, could keep rain off the buckpuck, and the conformal coat would resist the humidity and condensation.
edit: conformal coat is the standard material used in the electronics industry, but I've had good results with Plasti-dip on my bicycle electronics. In either case, use multiple light coats to get better coverage and less trouble with tiny pinholes letting moisture in.
Last edited by Steve K; 05-21-2012 at 02:23 PM.
for sealing the LED's, LEDSupply sells a product called LEDSeal - http://www.ledsupply.com/9013-07.php Its meant for outdoor products liek this. Also their PuckPucks are fully waterproof since they are fully encapsulated
I've been testing Ducky's Electro Seal spray-on on a number of outdoor mounted LEDs. But since then it has yet to go through a downpour while its on.
this stuff: http://www.carolinaboatoutfitters.co...-d1005-p-76490
you are correct, the wired buckpucks are confomally coated which makes then essentially "dunkable"
I have bought several ABS enclosures with clear tops to test the feasibility of outdoor fixtures.
I used one of make a fishing light runnig 8 green Lux1s with optics and a boostpuck off 12V
It ran well until the power outlet joint got corroded, water flooded in, and ruined everything on the inside.
I got the idea to drill 1" holes on the side, snake a PVC conduit in and epoxy around the joint to seal the plastic. The problem now is the air is completely still inside it, which insulates the heatsink, and it gets to a point where its so hot that the ABS starts to melt. Only way I have found to remedy the problem would be to force air through the conduit from one end using a blow-fan and have the other end covered with mesh as a exhaust. But for every piece of hardware that blocks the line of sight airflow is reduced and every bend it enounters the air flow is effectively eliminated.
I have converted from force air heatsinks to passive heatsinks and currently found that a tri-rebel star driven at 700ma works well with this TO-3 heatsink. Its hot but not so hot I cannot comfortably touch it.
Dale 2 ohm 1% 5w aluminum clad wirewounds level the rebels at around 680ma on 12V
My plan now is to see whether or not I can find six die-cast aluminum enclosures without costing me an arm and a leg or a size so large I cannot effectively use it and house the heatsink in it [or the LED itself] and cutting a 20mm hold on the lid for optics.
Current tests tell me for the current I'm working with JST connectors are sufficient. Installation of modules will use heatshrink over the connectors, which can be peeled away to expose them if modules needs to be swapped out.
The dusk to dawn sensor is currently wired to a receptacle [actually, two receptacles] which the 12V SMPS will plug into. The SMPS will be rated for 10A, but I speculate only 5.5A will be used.
4x Rebel tri-stars at 700ma, ~3A
2x XPG tri-stars at 1000ma, ~2A
the XPG tri-stars will be connected on one of these:
Since the patio is facing the back yard, these will act as on demand walkway lights that will illuminate the rear of our property between the garage and utility shed. Field tests gave me excellent cover and sufficient to identify trespassers without them being able to look into the windows. I can activate the reciever anywhere in the house using the keychain. My SMPS allows me to put at least 5A of LEDs on that remote control. The poor fellow that stumbled into our yard and accidentally kicked a bucket or a pot will get one hell of a surprise when I put those XMLs in...
Last edited by Illum; 05-26-2012 at 07:53 PM.
What a wonderful project! I like it. The last time I was in a big-box hardware store I saw some fairly inexpensive waterproof LED fixtures designed for outdoor use. They would have the advantage of being a turnkey installation. Just a thought.....
Here much of the waterproof LED fixtures are based on clustering 5mm LEDs, which if driven correctly works well for general illumination, but a new work bench has been added that was sized to accomodate as a useable surface to lay out outdoor barbeque gear/meats on. Illumination on these areas must satisfy at least two criterias: on par color rendition, and bright enough to comfortably work but not so bright one would have to squint.
Heres one of the original strings that hasn't been disassembled
This one was closest to the house, pristine condition, still works
The one is in between, minor corrosion on the ring, one LED is closed circuit
This one is parallel to the leading edge of the house, about 20ft from the center of the house. It has been repaired twice, the second time new CREE XRE emitters were laid on the heatsink, one LED is closed circuit.
First installation in November 2009 they have worked 24/7, considering the fact that these LEDs were not coated with dielectric spray on and were shielded only by a gutter mounted above it, I have no complaints. Having the freedom to mix and match LEDs on a common voltage rail makes me want to use the Nichia 219 Tri-stars over the work bench side. But I have little familiarity with these new LEDs. I do know the Rebel Warm whites used in the evaluation of a feasible budget CRI LED was a . It made the place feel like I was lighting it with low pressure sodiums.
these (the bare aluminum 1-1/4" variety) on my outdoor lighting project and they're still running strong. I just AA'ed the star to the canister and the canister to the (admittedly a bit too small) quasi-heatsink. Been running a ~75% duty cycle for about 18 months now including one of the hottest summers on record. Inside are some Rebel tri-stars running at 350mA. Getting the wires routed is a bit of a challenge thanks to my awful soldering skills and resultant cold solder joints (not a fan of RoHS solders).
A bead of some sort of adhesive will keep the lid in place and the windows on the lid are actual glass. Appears to be sufficient vertical clearance inside for an optic, but I've admittedly never experimented with such.
I'm using the same canisters on a different project that's about two-thirds complete (need only spend a few hours in the attic ... yuck), albeit mostly as additional radiating surface area and as a means of keeping dust off the LED's.
I apologize that this letter is so long; I did not have time to write a short letter