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LED light unit failed

Hi again.

I took off the led strip that failed and haven't done anything yet but the led that had lost brightness before the strip failed altogether looks very dodgy visually. Like it has failed really because the colour of the little bulb has changed from lemon yellow to darker yellow. So I suspect it is the one bulb that failed and not a connection. I would presume they are wired in series for all of them to fail to light up if one fails?

See on the picture below. The right light is the one that had gone dim/possibly failed(dark yellow) and the left one was a working one(lemon yellow). All working ones on the other strips are lemon yellow.

Do you think it was the old driver that damaged it? Also should I run the leds on 700mA or 500mA? What difference does it make?

LED_zps63606dcb.jpg


The wires are inside the aluminium body. I can detach the failed bulb from the strip, take off the lenses and then take off the wire from the star itself where they are soldered. What's the easiest to bypass the failed light? I don't even have a soldering iron.[DOUBLEPOST=1400660797][/DOUBLEPOST]The lenses came off easily so this is how it looks inside, bad job to start with?

There are two wires going to the right side and one on the left. This is the first led on the strip from the power cable side.
The rest of the leds have just one wire soldered on both sides.

LED2_zps99e7d70e.jpg
 
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Well it possibly looks damaged, the yellowing & browning of the chip.

This can be caused by
- Thermal overload due to too much current
- Thermal overload due to not being heatsinked sufficiently
- Not being a Cree device, but cheap Chinese copy.

Looking at your picture and knowing CREE product packaging, this doesn't look like a Cree product. (maybe wrong, might be old Cree product). Search for "cree star" in google images, you will get loads on star PCB shapes, but Cree LED's tend to be square rather than round and have Cree printed on the PCB (maybe wrong of course).

An interesting match I found is this
http://www.ledsales.com.au/shop/index.php?main_page=product_info&cPath=148_188_221&products_id=1334

An LED package that matches is....Warning word here is "Taiwanese"
http://www.ledsales.com.au/shop/index.php?main_page=product_info&cPath=148_188_221&products_id=984

So your LED's could be from same country of manufacture as your LED driver......:drowning:

In the mean time unsolder the two wires from the failed LED and join them together, simple "chocolate block" connector is fine for testing. Or for even quicker testing just hold a short piece of wire across the two soldered joints or use a pair of pliers anything to electrically bypass the failed LED.
 
ian_m said:
Looking at your picture and knowing CREE product packaging, this doesn't look like a Cree product. (maybe wrong, might be old Cree product). Search for "cree star" in google images, you will get loads on star PCB shapes, but Cree LED's tend to be square rather than round and have Cree printed on the PCB (maybe wrong of course).
Click to expand...

Thanks Ian.
I am not surprised. I already googled a bit and had my doubts about these being Crees, possibly cheap leds too along with the nice Chinese drivers :)[DOUBLEPOST=1400669212][/DOUBLEPOST]
ian_m said:
- Thermal overload due to too much current
- Thermal overload due to not being heatsinked sufficiently
- Not being a Cree device, but cheap Chinese copy
Click to expand...

Could I be running them on too much current with the new driver? It's on 700mA, should I changed the dip switches to 500mA or not?
 
sciencefiction said:
Could I be running them on too much current with the new driver? It's on 700mA, should I changed the dip switches to 500mA or not?
Click to expand...
Well if they are Cree LEDs rated for 700mA (as your original driver was) then 700mA is OK, but watch your algae as thus could be a huge amount of light.

Could of course be a failed Cree LED due to thermal issues. If it had not been attached fully the bar and overheated, it could have failed that way. Check if firmly attached to aluminium bar heatsink. I know a lot of early on DIY aquarium LED lights had failures due to the sticky thermal pads failing due to moisture allowing LEDs to come loose, which then over heated and failed.

However, if you suspect they are not Cree LED's you have to use your judgement. 500mA may prolong the life of the LEDs, but have you enough light then ?

Genuine Cree 3W star LED's are about £5 or more each, but no longer made.

Your LED's resemble Luxeon products, especially as you have the lens/optics, again no longer made (acquired by Philips ?).

However these @ £3 each, Lumiled star series look very similar and rated 700mA and not Chinese rip-offs.
http://uk.farnell.com/lumileds/rebel-star-es-nw200/led-rebel-star-es-nw200-700ma/dp/2115405

You would need to ascertain if your lens/optics will fit and how to attach to your aluminium bracket.
 
ian_m said:
Could of course be a failed Cree LED due to thermal issues
Click to expand...

No, I don't think they are Cree's. I was ripped off definitely.

Check if firmly attached to aluminium bar heatsink.
Click to expand...

Yes, firmly attached.

Well if they are Cree LEDs rated for 700mA (as your original driver was) then 700mA is OK, but watch your algae as thus could be a huge amount of light.
Click to expand...

They are very strong as they can burn the immersed plants near them but I've always ran them suspended above the water surface and never had algae in this tank. Now actually there isn't enough light going down there as the strips haven't worked together at the same time for months due the drivers and most my submerged plants melted. The immersed have overshadowed the tank a lot too.

However these @ £3 each, Lumiled star series look very similar and rated 700mA and not Chinese rip-offs.
http://uk.farnell.com/lumileds/rebel-star-es-nw200/led-rebel-star-es-nw200-700ma/dp/2115405
Click to expand...

Thanks for this. I'll have a look and possibly try them.

Just one question, what soldering iron can I buy that's cheap but sufficient to re-solder a few failed leds(presuming they'll keep failing :) )
I'll be definitely saving for a decent led fixture but it doesn't look good at the moment.
 
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Hi Ian,

I need to buy a third driver for this strip as I only bought 2 Osram ones which are on the working 2 strips.

I came across this one below from the same website. Is it any worse than the Osram or better do you think? For some reason in pounds it's around £38 from co.uk but from the Irish website it's €46 where the Osram is £29 from co.uk but €50 from the Irish so to me the below works out slightly cheaper though I don't care for the €4 difference but just curious what you think..

http://ie.farnell.com/lumileds/929000614503/led-driver-ac-dc-0-7a-80v/dp/2115974?Ntt=929000614503

I ordered 2 amp chocolate block connectors and will test the strip bypassing the possibly failed led and will order the leds you recommended too to replace when I train myself in soldering. Do I need a multemeter to test the connection after I solder a new led or if they light up I am good to go and can save myself the money for a multimeter?
 
Its OK for 700mA but unlike the earlier one hasn't got switch settable lower currents. Can be used to dim lights but only with external controls.

The LED type you should be looking for replacements need to be the same star type package that will be suitable with your lenses. You will need to check this or else you will replace your LED's and find the lenses won't/don't fit.

If they light up I assume good to go.

If you want a multi meter just for testing connections any cheap one like this will do. http://www.tlc-direct.co.uk/Products/TMDM1.html. As long as it has a resistance setting, though more useful is audible continuity, ie if beeps if connection is good.

Personally at home I have http://www.tlc-direct.co.uk/Products/TMDL9206.html, which I got as it has a large easy to display and auto-ranging. I have worked with so many meters where hard to read display makes them hard use. My last meter I bought whilst at school (has move'y needle type meter) in 1980 and still works and is still used. But then my career is electronics.

Last time I was in B&Q I noticed they has a range of multi-meters at quite good prices.
 
Thanks Ian so I'll stick with the Osram model.

I am not sure how to check if the lenses will fit but they have the diameter of the star pcb which is 2cm and it has just two holes/dents on the bottom of the plastic cover at opposite sides for the two cables soldered to the star to come out, nothing special really. The lenses is glued to the star with some "white residue glue" which I am suspecting is superglue?

I'll just order a couple of stars and check before soldering :) I couldn't see the measurements of these from farnell.
I'll probably ruin one of them first so I am getting a couple of spares :)
 
Hey Ian, I am reviving this thread again as I still haven't fixed the lights. I was delaying it for ages because I wanted to buy proper light but to be honest even shop purchased ones have been failing on me these days so no point spending a fortune for a 5f tank light if I can learn how to fix these.

The drivers you suggested as replacement are perfect and still working fine. Thanks. The problem is two of the LED bars have not been working in years due to a failed LED on each, subject to further identification..... I took out one of the led strips last Sunday and somehow got lucky by figuring out which led is at fault. The soldering job on it was horrible. I bypassed it and the led strip lit up. But I still need to replace the failed led eventually.

I am going to purchase a soldering iron, star leds(perhaps the same ones you suggested back then), thermal pads, etc.. and try to fully fix the lights by replacing the failed leds. Thankfully one of the strips is still fully working after all these years but my plants have been totally struggling with just one strip.

My question is, are the star leds you previously suggested from the links above still the best solution? I was also wondering if it's possible to get some coloured leds because the lights currently as a whole are very "white" and I like a bit of red hue personally? And if yes, which ones that are a match for that setup?

I also haven't grounded them. What's the best way to do that? The power goes from the socket, to the driver where the red, blue and green(ground) wires are connected. . Then from the out connectors on the driver that lead to the leds, only the red and blue wires are connected, leading straight to the leds, meaning no ground wire in that section. There is no "ground out" connection on the driver, just ground in and the latter is connected to the cable part that comes from the socket.
I see that on your diagram from first page that the ground wire should be also coming from the driver and leading to the leds, and there I should connect it to the aluminium body perhaps via a bold of some sort.
I can screw the ground wire to the aluminium body of the light unit on the side of the leds but its other end isn't connected to the driver at all so not sure if that will work? Where is that ground wire supposed to be connected, the part coming out from the driver?

I am sorry for the stupid questions but I have no clue whatsoever as you can see....

Thanks a lot.
 
The output from the driver will be much lower voltage than the input to the driver. Probably about 12V, which isn't capable of pushing significant current through the human body and therefore doesn't need any earth/ground.
 
Morning again...

did you ever get a soldering iron ? I notice Ebay sells tin/lead solder (60/40 Sn/Pb), this solders a lot easier than lead free stuff as it tends to "wet" a lot easier. But is not environmentally friendly (though that is debatable) and cannot be sold in a commercial products manufactured after 2006.

Yes you can change any LED to any colour you like, provided they are rated 700mA, the same current as your white ones. You need to look at some commercial LED lights to gauge how they mix their ratios of white, red, green and blue to get some idea of what you should be aiming for. Another option is to change some to warm white, as it sounds like yours are cool white.

The earth wire, if you decide to fit it is as per my diagram on below.

leddriver1_zpsd61614d8-png.21269.png


Not strictly necessary as the "proper" LED drivers, at least the Osram ones are properly insulated, it quotes 3700 Volts isolation mains in to LED out. A lot of commercial LED fixtures, made of aluminium are not earthed I notice, as they only have two wires connecting to the fixture.

What the earth does is provide a current path big enough to blow any fuse or trip a breaker if the mains live accidentally gets connected to the aluminium. Thus cuts the supply before the current passes through a person touching the aluminium (a bad thing).
 
Thanks Ian. I never bought anything at all. I'll take a look at the soldering iron.

The earth wire, do I need to connect a separate earth wire to the earth-in that goes in the driver? And if I connect it via a bolt to the aluminium body, do I need to insulate the part of the bolt that will be on the outside in case I touch it?
Basically from the setup on the diagram above everything is connected by the earth wire that comes out of the driver and leads to the aluminium body.
 
Dr Mike Oxgreen said:
The output from the driver will be much lower voltage than the input to the driver. Probably about 12V, which isn't capable of pushing significant current through the human body and therefore doesn't need any earth/ground.
Click to expand...

Thanks Dir Mike. It would be easier if I don't need to connect earth wire from the output because that's a lot of wires that will be hanging from 3 led bars ;)
I have been using just one led strip without being grounded for a few years now. I've avoided touching it when on :oops:
 
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