Troubeshooting DIY LED

[Stones]

I've read through nearly all of the DIY LED threads on several forums as well as followed all the instructions from RapidLED on wiring a series of CREE XP-G's to a Meanwell ELN-60-48D driver but I just can't seem to get my light to work.

First off, I wired in a potentiometer to a 10V power source and to the Meanwell driver. Using a multimeter, I'm getting 350 mA with the potentiometer on full and the Meanwell driver internal pot set to the minimum with the multimeter connected to the V+ and V- leads from the meanwell. If I turn up the internal pot on the driver, I can bring my current from 350 mA up to 1.3 A so I know I'm getting power to the LED series as the driver and potentiometer are working correctly.

Now after connecting the V+ and V- leads from the Meanwell driver to my series of LED's, none of the LEDs will fire. I assumed I had a bogus LED so I tested them all indiviudlaly with a battery and sure enough, the 1st LED in the series was fried. After removing the LED from the series, I reconnected the V+ and V- leads from the Meanwell driver and the LED series still won't ignite. When I connected my multimeter in series with the LEDs after the final LED, I'm getting no current reading so I'm not getting any power going through my circuit.

I then went and tested all of the LEDs indiviudally again with a battery and they will only fire up when the battery is connected to the + and - posts on an individual LED. If I try to connect 2 or more LEDs together in a series none of them will fire. However, if I connect the battery to the + terminal of the 1st LED and to the + terminal of the 2nd LED in the series, the 1st LED will fire showing that the wiring/soldering between the two LEDs is sound. When I then connect the battery to the + terminal of the 1st LED and the - terminal of the 2nd LED, neither of the LEDs fire up when both of them should.

Any help would be greatly appreciated. I wasted about 4 hours last night troubleshooting this thing and ended up tearing out all of my wiring and redoing it to no avail.

Here is a pic of how I have the LEDs mounted to the heatsink. Ignore the 1st LED with the black marker as that was the dud.
http://i53.photobucket.com/albums/g47/prestieb/IMG_7716.jpg

Here I pencilled in how I had the LEDs wired together before removing the wiring last night.
http://i53.photobucket.com/albums/g47/prestieb/IMG_7716_2.jpg

Here is a close up of how i have the LEDs wired. I only resoldered the first 2 LEDs together again for testing purposes and was unable to get both to fire at the same time off of a battery.
http://i53.photobucket.com/albums/g47/prestieb/IMG_7719_2.jpg

[mike31154]

What size wire are you using there to connect the LEDs? Looks a tad too large to me, which makes soldering difficult since you need a lot more heat with larger guage wire. Solder joints don't look too good in the last pic. My guess is you had a cold solder joint and all it takes is one to prevent current flow through your series of LEDs. You may end up frying all your LEDs or the small wire runs on the starboard by needing too much heat with large jumper wires to get a good solder joint. Also, not sure the way you've secured them with screws is the best way to go.

[Stones]

Thanks for the help Mike. Originally I had used smaller gauge wire but I tore all of that out to troubleshoot the LEDs individually or in shorter series. I guess I can pick up smaller wire and re-solder all of the LEDs to see if that solves the problem as its 16 G wire that I had used for the last pic.

At the time I purchased the LEDs, I didn't know that there was thermal adhesive available to glue the LEDs to the heatsink so I drilled and tapped the heatsink to mount the LEDs instead. It was a painstaking process and I will not be doing that again if i build another LED light.

[StirCrazy]

just looking at some of the solder in the pictures they do look cold. did you pre tin all the pads? you want to pre tin the pads and the wires then solder them togeather that way will give you a much sounder conection.

also with the meanwells you want to adjust the max curent down to 1000mA befor you hook it up to your aray to prevent over current.

Steve

[martinmcnally]

Interested to see if you get this working because I ended up giving up on mine after I couldn't get it working. I had major problems with soldering and wiring. Apparently you need flux core solder... I didnt know that and not really sure if I have it or not still haha.

Good luck!

p.s. you can get thermal glue at Rona!

[Stones]

Thanks for all the pointers guys! I was using rosin core solder and did pre-tin all of the terminals on the LED pcb's but I didn't pre-tin the tips of the wire. I'm going out to pick up a better soldering iron and some thinner wire here tonight so I'll let you know how i make out.

I've done a few small soldering jobs in the past (LED moonlights) and have never had any issues but I guess there is a first for everything...

[eli@fijireefrock.com]

like most said keep you screws and soldering job is clean no loose wires or solder touching the star. And it is better for agonizing drilling and tapping into the heat-sink for if any problem arises later with individual led.
check some of the work i done on my arrays.
http://i726.photobucket.com/albums/ww269/chefely/led/IMG_0606-1.jpg?t=1301959527
here is another
http://i726.photobucket.com/albums/ww269/chefely/led/IMG_0595-1.jpg?t=1301959986

[martinmcnally]

Well my prayers have been answered. This might help you too:

http://www.rapidled.com/servlet/the-127/Solderless-Connector-for-CREE/Detail

[GMGQ]

I agree with the others, the soldering connections seem to be the problem. You need to tin the pads of the LED, tin the wire, then solder them together.

http://reefblog604.files.wordpress.com/2011/03/img_4013.jpg?w=300&h=225

Helps a LOT if you have a high wattage soldering iron. You want to heat up the target, not the solder wire. Then touch the solder wire to the target, and let the solder melt onto it.

Careful of the flux (the clear stuff that comes out of the solder wire). If the flux is coating the pad or the wire, then that could be preventing a conductive connection. Don't be afraid to give the wire a good yank after you've soldered it. It should be ROCK SOLID. If it comes off, then obviously the connection was poor.

[mike31154]

If you enjoy soldering and builiding your own arrays with heatsinks, wiring, screw tapping, mounting, fine, but if not, more and more options are appearing on the market that are plug & play without breaking the bank. A net search using "High Power LED E27 base" will yield a multitude of info on LED options with conventional screw in type bases. Some of them will work straight off your household AC while others work with a 12VDC supply. Personally I like the MR16 two pin 12VDC form factor. You could arrange a bunch of these with little effort since they push in to the MR16 base very easily and it's not as large a connector as the conventional household E27 screw in base. I can see this being somewhat more water resistant as well, with a small rubber gasket over the base which you would then push the lamp pins through. You could also run them directly from a 12VDC source like a deep cycle battery, provided you have a reliable way of keeping the battery charge at the required level to run the number of lamps you plan to use. No drivers converting AC to DC to run your LEDs, which are after all DC devices. You could also add a potentiometer to dim the LEDs directly in line with the voltage source. The electronics geeks could make this dimming feature automatic, I'm sure. Below are just a few links showing what's available these days. A little more patience, these things will start dropping in price as LEDs slowly start replacing the CFLs which replaced the incandescents in our homes. If/when one of these burns out, yank it & replace it, simple.

If you're still keen on assembling the parts required to DYI a soldered array, knock yourselves out, but I'm waiting a little longer and will build either an E27 or MR16 based lighting system when the price & availability of this form factor drops in price a little more.

http://www.ledlightbulb.net/store/index.php?main_page=index&cPath=4_31

http://www.dhgate.com/15w-high-power-led-bulbs-e27-base-with-cree/r-ff8080812af9fc17012afa0b9aa25384.html

http://www.ledlightsworld.com/mr16-1x3w-led-spotlight-p-99.html

I know this doesn't help solve the problems with your current LED job, but so many folks are getting caught up in this DIY LED array craze when there are easier options on the horizon.

[StirCrazy]

If you're still keen on assembling the parts required to DYI a soldered array, knock yourselves out, but I'm waiting a little longer and will build either an E27 or MR16 based lighting system when the price & availability of this form factor drops in price a little more.

http://www.ledlightbulb.net/store/index.php?main_page=index&cPath=4_31

http://www.dhgate.com/15w-high-power-led-bulbs-e27-base-with-cree/r-ff8080812af9fc17012afa0b9aa25384.html

http://www.ledlightsworld.com/mr16-1x3w-led-spotlight-p-99.html

I know this doesn't help solve the problems with your current LED job, but so many folks are getting caught up in this DIY LED array craze when there are easier options on the horizon.


I think your missing the point here. your first eg is 90 to 180/bulb and still are a 60 degree output so you will need a fair amount, and they come in cool, nutral and warm white.

the second eg is not practical for a fish tank as it is a 360 design so 70% of you light is going where you don't want it.

for the third eg 9 bucks each ya they will work but color is limited as they are for household track lighting and they still have a transformer.

the point of people building them there selves is

1, to save a tone of money. for 200 to 500 you can buils a system that would retail for 800 to 3000.

2, custom aplication. you can pick your lense, spacing, and color combanation.

3, features.. all the examples you showed are non dimable.. I was looking at leds for my lights down stairs and non dimable ones are 10 bucks each.. dimable ones are 30 bucks each for a 40 watt bulb replacment.

another issue you have to look at is what lind of LED are they using and you also need outdoor rated LEDs fixtures or they will burn out quite quickly. there have been sever house hold lighting products comming out laitly with cheep LEDs which use substandard methods of altering the color because it is way cheeper (like paint on the surface of the LED) this has been flaking off and causing color shifts ect.. when the people are building there fixtures they are using Cree for the most part which has way more out put than say a edison LED of the same wattage. so it not just about conveniance.

Oh and there also the "I built it myself" factor which to some is very satisfying

Steve

[mike31154]

I simply provided the links as an example of what's available currently and if folks are willing to wait a little longer, or contact the manufacturers for different colour options, I'm sure they would be able to assemble something suitable. I did a quick search and threw a couple of links out there for people to get the idea. It's an alternative if you're prepared to do additional research. Getting away from pure DIY a little, I know, just pointing out that there are other ways to build LED fixtures for salt water aquariums apart from soldering.

[GMGQ]

I agree that retail is not the same as DIY in that you get more and pay less for a DIY setup.

The retail LEDs are old technology. DIY with Cree, or even knockoff Cree LEDs, are waaaaay more powerful. One retail LED is not even in the same league as one Cree LED, so they cannot be compared as apples to apples.

[StirCrazy]

The retail LEDs are old technology. DIY with Cree, or even knockoff Cree LEDs, are waaaaay more powerful. One retail LED is not even in the same league as one Cree LED, so they cannot be compared as apples to apples.

ahh but a lot of new fixtures are comming out using new cree leds now so we have to watch how we compare things.

Steve

[GMGQ]

True... Still comes back to price then.

This one is still $1899 for a 4ft fixture, with i'm guessing 48 LEDs:
http://www.canreef.com/vbulletin/showthread.php?threadid=74421

ahh but a lot of new fixtures are comming out using new cree leds now so we have to watch how we compare things.

Steve

[StirCrazy]

True... Still comes back to price then.

This one is still $1899 for a 4ft fixture, with i'm guessing 48 LEDs:
http://www.canreef.com/vbulletin/showthread.php?threadid=74421

yup and you can buy a kit with everything you need including optics, but no heat sink, for 48 LEDs for about 400 bucks.

Steve

[Stones]

Thanks for the links guys. I'm still preferring to do this total DIY as the fixture is for a Fluval Edge planted tank. I could have went with 2 MR16 base LED bulbs that would have plugged right into the Fluval edge fixture but I opted to go with 9 Cree XP-G 3W LEDs instead as I assumed I'd get better coverage and I enjoy most DIY projects. This is the 1s time I've ever had any problems with a DIY build and thanks to some of your comments, I'm assuming it was likely due to a build up of flux while soldering.

I haven't been able to find any wire thinner than 18 G locally so I still haven't resoldered the LED array. I did pick up a better soldering iron and a solder sucker to remove the excess solder from the previous job. I'll let everyone know if I do manage to get this build up and running.

I had seen the "solderless" LED connectors but opted to go without them due to mounting options. Very neat idea though.

[HeliWrench]

Seems to me the screw head are grounding/shorting the LEDs to the heat-sink. Maybe try using smaller head screws that don't contact the terminals on the LED stars.

Let me know if this helps.

HeliWrench


Here is a pic of how I have the LEDs mounted to the heatsink. Ignore the 1st LED with the black marker as that was the dud.
http://i53.photobucket.com/albums/g47/prestieb/IMG_7716.jpg

Here I pencilled in how I had the LEDs wired together before removing the wiring last night.
http://i53.photobucket.com/albums/g47/prestieb/IMG_7716_2.jpg

Here is a close up of how i have the LEDs wired. I only resoldered the first 2 LEDs together again for testing purposes and was unable to get both to fire at the same time off of a battery.
http://i53.photobucket.com/albums/g47/prestieb/IMG_7719_2.jpg

[mark]

^ looks like the OP is using nylon washers so shouldn't be shorting