Black Box mod help

John08007

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I have changed out some of the LED's on my black box after some of the originals burnt out. The Led's that I used are all rated at 3.2-3.V 700 ma, violets are 3.5-4V 700 ma. The box I have has 2 channels with 26 LED's in series and 1 channel with 3 LED's in series. It works fine for a few weeks but I still occasionally burn out an LED. I haven't looked to see if it is a new or old LED that blows out. My question is what LED driver would I need to replace mine with to keep this up and going with these LED's. I currently have a PWM dimmer but would want a 0-10V to use with my apex. I believe the specs on the drivers installed are 100-240V input, 55-85V output, 570-590ma

If need be I can replace all the original LED's with the new ones to guarantee a uniform spec and put the violets on the channel with 3 led's to keep them separate from the ones with a higher voltage
 

oreo54

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Finding "exact spec" replacement drivers is a challenge.
I'll start w/ a low end driver:
https://www.ledsupply.com/led-drivers/mean-well-lcm-u-series-with-dimming

you'd run at 350mA (40W driver)..or 500mA (60W driver).

Thing is your replacement diodes are either poor to begin with or the thermal compound wasn't correctly applied..
dimming effectively should "cut" the current on average..

Meanwell has anothe series that sort of works but believe for the correct V out you actually increase mA's..
 
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John08007

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That looks like a great choice because it looks pretty versatile with the dip switches. Mathwise what am i looking for? I multiply the number of leds in series by their recommended voltage and match the ma?
 

oreo54

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Technically you add the voltage at the current you want....
Example:
Forward Voltage is 3.5V @ 350ma, 3.7 @ 800ma

If you want to drive them at 350mA and you have 26 of them..
The driver needs to be able to "do" 91 volts output..
1.25W per diode..(3.5 x .350)
32.5W total for 26 in series..

96.2V for 800mA..
2.96W per diode (3.7 x .8)
77W total for 26 diodes in series.

You would need to measure the ACTUAL voltage of the diodes at the desired current.

Other than that assume, hopefully, what they state is correct.

Since "lots" vary considerably w/ cheap diodes it is more or less a shot in the dark.

PROOF would be to hook the driver to the string and see if the ACTUAL voltage at that current is below the MAX voltage of the driver..so you aren't topping out on voltage..
AFAICT .. topping out isn't harmful per se but the current draw will not be the desired current..


side note: your current driver is "rated" at 50W approx max output..
85 X .590
 

Backreefing

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Ain’t this a lot of trouble to go through for a $65-$100 unit ? But if you like to tinker with it. Go ahead . eBay may have what you want. You should size the driver to supply 120% of the wattage. If you make it exactly it could be like driving a car at wide open throttle, won’t last to long .
I think the blue side of BB units needs the most work IMO and the white side can have crazy colors like 3000k and not enough blue in the unit as a whole ( just me ) . Good luck
 
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John08007

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Ain’t this a lot of trouble to go through for a $65-$100 unit ? But if you like to tinker with it. Go ahead . eBay may have what you want. You should size the driver to supply 120% of the wattage. If you make it exactly it could be like driving a car at wide open throttle, won’t last to long .
I think the blue side of BB units needs the most work IMO and the white side can have crazy colors like 3000k and not enough blue in the unit as a whole ( just me ) . Good luck
I fig an led is an led, whats it matter if its inside an $80 black box or an $800 radion? I have a 24×24×30" tall tank. I have 2 black boxes bolted together giving me 4 channels to control. I think with some work and my apex i should be able to make a solid light out of this using pretty much just the cases and led boards as a foundation.
 

Backreefing

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Cool , can I ask what spectrum you choose for the blues ?
 

Backreefing

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IMO splitting the between 40%420nm and 60%470nm is what i would chose , however 450nm is crisp and makes corals pop .
the problem with LEDs is they are narrow in wavelength. A 450 really is 450not much else. I have been noticing that BB makers will go with say 470 nm only with just a couple of 420 s . Lately.
 

Backreefing

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Also BB makers leave out 480-500 altogether. And what is with 300k and 4500k ? I would slap some more blues in there and go with 6500-14000k just kicking it around.
 
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