DIY Reef Light HELP

[Amphibious Wallet]

If you haven't yet, you should check out steve's leds for name brand stuff at good prices currently.

Thanks for the heads up, I may do just that if chucking it over to the other hemisphere doesn't kill me.

300 mA is the maximum he should run these chips at, actually. They are probably rejects and have bad efficiency, but he can counter that by running a lot parallel.

Agreed. Most 1W and 3W LED's from youknowwhere look identical and might just actually be. Those labelled as 5W on the same physical form factor have a visibly larger square of phosphor. On the plus side, more soldering practice running double the LED lol.

 

[mk_reefs]

You shouldn't run these junk chinese led chips at 100% power anyway.
They will overheat and burn out in under one year and give you terrible efficiency. No led chips have a linear efficiency power curve, but these chinese rejects are particulary bad.
I am using them too, but running mine at 30% power max. Just means i need more LEDs to reach the required par, but they are so cheap it doesn't matter.
Right now i am running 180 watts of leds at 40 Watts over 15 gallons.
You may want to look at meanwell drivers. They are dimmable.

If they do burn out definitely going with the 3535 crees

 

[Tavero]

If they do burn out definitely going with the 3535 crees

You have a whole bag of 3w bulk LEDs. Just use them all in one light and run them at 20% power. No reason not to use them.
Maybe mix in a few whites and put them on a separate ciruit with variable dimmer.

 

[oreo54]

If they do burn out definitely going with the 3535 crees

My experience it is hit and miss regarding failures of these cheap diodes.
One person found that the heat transfer from the "egg" to the star board was not addressed well
as in no contact/no thermal compound/no solder.
Actually bought the "loose" ones and thermal siliconed them to the heat sink.
Failure rate dropped significantly.

Of course one has to bend the "ears" out to avoid contacting the heat sink.
They do break fairly easy.

And yes, most black boxes using "3w class" diodes run at around 550mA which is where one really should start.
Less is more so to speak.

At 100 pieces for $8 bare eggs.. well what can one say.

https://www.aliexpress.us/item/2251832619066511.html?pdp_npi=2%40dis%21USD%21US%20%249.70%21%248.54%21%21%21%21%21%402101d1b116700833119556128e5b1e%2164331851725%21btf&_t=pvid%3Ae6d346dd-f103-4404-b743-404ab409e5f9&afTraceInfo=32805381263__pc__pcBridgePPC__xxxxxx__1670083312&spm=a2g0o.ppclist.product.mainProduct&gatewayAdapt=glo2usa&_randl_shipto=US

Opp's I SEE you are mounting the eggs to boards.

https://www.aliexpress.us/item/2251832560006939.html?spm=a2g0o.ppclist.product.12.550dyykryykrLh&pdp_npi=2%40dis%21USD%21US%20%246.39%21%246.39%21%21%21%21%21%402101d1b116700833119556128e5b1e%2112000019873552896%21btf&_t=pvid%3Ae6d346dd-f103-4404-b743-404ab409e5f9&afTraceInfo=32746321691__pc__pcBridgePPC__xxxxxx__1670083312&gatewayAdapt=glo2usa&_randl_shipto=US

Also inexpensive..

 

[Nonya]

My experience it is hit and miss regarding failures of these cheap diodes.
One person found that the heat transfer from the "egg" to the star board was not addressed well
as in no contact/no thermal compound/no solder.
Actually bought the "loose" ones and thermal siliconed them to the heat sink.
Failure rate dropped significantly.

I never lost any of the old large old-school LEDs. I always bought them separately from the heat sinks and mounted them with thermal epoxy myself.

 

[Koh23]

You shouldn't run these junk chinese led chips at 100% power anyway.
They will overheat and burn out in under one year and give you terrible efficiency. No led chips have a linear efficiency power curve, but these chinese rejects are particulary bad.
I am using them too, but running mine at 30% power max. Just means i need more LEDs to reach the required par, but they are so cheap it doesn't matter.
Right now i am running 180 watts of leds at 40 Watts over 15 gallons.
You may want to look at meanwell drivers. They are dimmable.

Nope.....

Chinese 3w leds, without any driver, connected to 12v power supply, 3 in series x parallel.... Soon hitting 10 year mark of constantly working.

Leds are rated to 700mA, 3,6-3,8v, with 3 in series, each gets 4v, calculate vdrop, they get exactly 3.6v each....

And connect them to any pwm dimmer, so you can adjust power... No problems at all.....

Its not the current that kils leds, its a heat. Ensure great cooling via adequate alu profiles and fans, and no worries.

Chinese led drivers are mostly 300mA, sometimes 600mA.....

 

[Tavero]

Nope.....

Chinese 3w leds, without any driver, connected to 12v power supply, 3 in series x parallel.... Soon hitting 10 year mark of constantly working.

Leds are rated to 700mA, 3,6-3,8v, with 3 in series, each gets 4v, calculate vdrop, they get exactly 3.6v each....

And connect them to any pwm dimmer, so you can adjust power... No problems at all.....

Its not the current that kils leds, its a heat. Ensure great cooling via adequate alu profiles and fans, and no worries.

Chinese led drivers are mostly 300mA, sometimes 600mA.....

Just because your LEDs are technically still emitting light doesn't mean that there is no damage. And after 10 years at 100% power i can guarantee you that they are done for.

While i agree with you that it is heat that is killing LEDs, electical power is energy and will produce heat as undesirable waste product. More energy means more waste heat and with a chip the size of 1mm2 it is physically impossible to tranfer enough of the 2.5 watts of heat to keep the silica under 100°C no matter how your heatsink on the other side looks like.

Also, the efficiency will be absolute garbage at 100% power.

 

[oreo54]

Nope.....

Chinese 3w leds, without any driver, connected to 12v power supply, 3 in series x parallel.... Soon hitting 10 year mark of constantly working.

Leds are rated to 700mA, 3,6-3,8v, with 3 in series, each gets 4v, calculate vdrop, they get exactly 3.6v each....

And connect them to any pwm dimmer, so you can adjust power... No problems at all.....

Its not the current that kils leds, its a heat. Ensure great cooling via adequate alu profiles and fans, and no worries.

Chinese led drivers are mostly 300mA, sometimes 600mA.....

Heck many Meanwell power supplies can have their voltage tweaked to match the diode V(f)

Wouldn't kill anyone to a a few pennies cost resistor at the end of each 3 diodes for current control..


Btw you use amps not mA's in the formula.
12-(3x3.6) ÷ say .5A = 2.4 Ohms.
Still need to calculate what wattage resistor

 

[Tavero]

Heck many Meanwell power supplies can have their voltage tweaked to match the diode V(f)

Wouldn't kill anyone to a a few pennies cost resistor at the end of each 3 diodes for current control..


Btw you use amps not mA's in the formula.
12-(3x3.6) ÷ say .5A = 2.4 Ohms.
Still need to calculate what wattage resistor

Thanks.
I didn't even realized that Koh23 is running his LEDs directly on a 12V power supply. If that's the case and he thinks this is fine, then i doubt that the LEDs are actually running at 3W. They were probably saved by limitations or internal resistance of the power supply.

I still want to repeat here for anyone else interested in DIY projects that it is absolutely NOT recommended to run LEDs directly on a power supply.

 

[Koh23]

Agree, its not recommended, but, almost 10 years ago, it was the fastes way

 

[Nonya]

Chinese led drivers are mostly 300mA, sometimes 600mA.....

You can get them in just about any amperage and voltage. Check Aliexpress.

 

[Nonya]

Agree, its not recommended, but, almost 10 years ago, it was the fastes way

It's fine as long as you used the right resistor on each branch.

 

[Koh23]

No resistor, like i said...

Pc power supply, 3 diodes in series, thats it. For white, blue, uv diodes. Reds needs lower voltage, so, 4 in series.....

Only thing to consider is, each series is 0.7A, so, not to exceed power supply capabilities, but since any decent pc power suply can give 16-20A per 12v channel....really its hard to overload power supply.

Also, dimmer is rated at 8A, so, one dimmer can regulate 11 series (33 diodes).

Thats how i (most of us here) did it way back, today i will probably go different route, but back in days, some things were hard to get, long waiting time, etc.....

 

[Tavero]

Thats how i (most of us here) did it way back, today i will probably go different route, but back in days, some things were hard to get, long waiting time, etc.....

Speak for yourself, lol. When i built my first DIY lamp 15 years ago, led chip did actually still cost money. I and many others didn't dare to run them directly on a power supply. Even at that time, cheap but inefficient linear drivers were the preferable option.

 

[Koh23]

Well, here was opposite...

Diodes were cheap, we buy them in packs 50-100 pcs...

But, drivers, dimmers, power supply...that was expensive, and require months of waiting, often just to realize that package is lost, and it will newer arrive...

So pc power supply and combining series+parallel was the way to go....

 

[mk_reefs]

Update:

New drivers came in, burnt out those 3w LEDs, I bought 2 -10 packs of 5w LEDs, both blue and royal blue and it looks like it matches my 50w nicrew that I'm supplementing my Waterbox with at 100% blues. I highly doubt it's running at a full 5w though..


Next is to pull the old PCB boards out solder back the connections and then epoxy them back in place. Maybe get a full test day in later this week...

 

[Tavero]

Update:

New drivers came in, burnt out those 3w LEDs, I bought 2 -10 packs of 5w LEDs, both blue and royal blue and it looks like it matches my 50w nicrew that I'm supplementing my Waterbox with at 100% blues. I highly doubt it's running at a full 5w though..


Next is to pull the old PCB boards out solder back the connections and then epoxy them back in place. Maybe get a full test day in later this week...

Some people just don't want to take advise and need to learn through own experience and brute force huh.
Well you do you. Good luck

 

[oreo54]

Update:

New drivers came in, burnt out those 3w LEDs, I bought 2 -10 packs of 5w LEDs, both blue and royal blue and it looks like it matches my 50w nicrew that I'm supplementing my Waterbox with at 100% blues. I highly doubt it's running at a full 5w though..


Next is to pull the old PCB boards out solder back the connections and then epoxy them back in place. Maybe get a full test day in later this week...

Sounds like your orig are "1W class" diodes..
Even the cheap "3W class" ones "usually" won't fail at 600mA unless heat transfer is really poor or
you got really unlucky.
800mA is where many approach an actual 3W rating.

5W diodes are generally 2 cores run in parallel thus keeping the same V(f) but splitting the current in half.
If the V(f) is listed above 3.5V-ish (7V) then they have 2 cores in series.
Anyways not that important.

Just make sure any glues/epoxies have good thermal transfer properties.
And you don't need the 2pt thermal epoxies. Just good silicone glue.

 

[mk_reefs]

Sounds like your orig are "1W class" diodes..
Even the cheap "3W class" ones "usually" won't fail at 600mA unless heat transfer is really poor or
you got really unlucky.
800mA is where many approach an actual 3W rating.

5W diodes are generally 2 cores run in parallel thus keeping the same V(f) but splitting the current in half.
If the V(f) is listed above 3.5V-ish (7V) then they have 2 cores in series.
Anyways not that important.

Just make sure any glues/epoxies have good thermal transfer properties.
And you don't need the 2pt thermal epoxies. Just good silicone glue.

They lit up, flashed, went really dull and burnt out, I can get a Kill A Watt tester and plug them in and see what they run. I recently contacted Nicrew and asked what LEDs they were running in their fixtures. They told me 3w 3535 which I'm guessing maybe cree. This is a fast project and I really hate looking at this Nicrew hanging off the side of the tank but also fun doing something that hasn't really been done before. The Nicrew 50w has 12 blue LEDs that's why I chose the 6 in series on the PCB to put them into the bar lights to get 12. So far the acros seem to be loving the extra lighting. Also not sure what Taveros comment is about... The light is very close to the one I'm supplement with maybe a tad less but so far I'm happy with it. For anyone interested I'll post another update. Thanks for the help guys. What glue would you recommend?

 

[mk_reefs]

I'll add I have every intention on making this project better as time goes on, an extra set of bars are only 20$. First I have to see if it's achievable through trial and error. Thanks again.