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Discussion Starter · #1 · (Edited)
Hi all,
I have been lurking for over a decade. I did a custom planted tank hood 12 or so years ago with T5 bulbs. With the extra at home time with Covid19, I decided to recommission my 125g Tall tank from the garage and build a custom stand. I started this tank with organic soil, capped with black beauty and a dry start method. I bought some 100wLED flood lights from Amazon but have had little success growing a carpet of monte carlo. So long story short, I have decided (with the urging of this community) to do a custom LED light fixture. I think I will do a custom hood too so here are some details on my thoughts.

Tank Size
60" wide, 18" depth, 26" Tall

Parts
Heatsink - 1/16" 18"*60" Aluminum
LED's - ‎ Bridgelux V13C THRIVE 976-BXRE-65S2001-C-74-ND‎ (12), Bridgelux V10C Thrive BXRE-50S1001-C-74 (6)
Controller - TC421 - WIFI Controller with LDD-350LW to drop the voltage from the power supply to 12v.
Power Supply - Meanwell 36v AC/DC Converter LRS-350-36
Drivers - LED Driver Meanwell LDD-1000HW (3) 6 led's per driver

Example Wiring diagram (Note - I will use 6 led's per driver)


My Tank
Wood Room Property Wall Interior design


My question(s)
Does this selection make sense?
Will the 1/16 aluminum sheet be enough as a heatsink?
Any concerns, or suggestions?

Thanks everyone
 

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You need 1 driver per COB
36V is borderline for the COBs as well considering you "lose" 2-4V in translation..
36V plus LDD means 32-34V out max.
Typical V(f) of V10 is 34.4V


Two COBs in series would require 68.8V out
Two in parallel cuts the driver current in 1/2..
Actually doesn't hurt but you likely won't get the expected output..


As to 1/16 al plate.. ????
Your talking about dissipating over 500W of heat
1A x 34V x 18 COBs ...
 

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Discussion Starter · #3 · (Edited)
So let me take a step back, I think I offered a solution instead a problem to a forum with experts. The 2 100w Flood lights didn't cut it, and forum members suggested a DIY LED solution. Reading this thread I extrapolated his solution for a 80gallon tank as a primer for mine (made mine 50% bigger due to bigger tank). So the problem I am trying to solve is growing plants in my 125g Tall tank. I feel like I don't have adequate coverage, and proper lighting intensity at the substrate. I was shooting for a solution that handled both of these problems with roughly 250w. I was expecting to run these LED's at 1/2 of their maximum to try to extend their life and not generate too much heat.

So to address your points.

1. 36v powersupply. This was a mistake. I changed my plan to Meanwell 48v AC/DC Converter LRS-350-48. Thanks for that catch.
2. One Driver per COB. Is this a hard requirement, or a suggestion for a nube so I don't electrocute me and my fish? This design adds lots of cost, and I was trying to trade off flexibility for cost. Can I not combine multiple COB's into a circuit (Parallel/Series) and save the number of drivers?
3. Heatsink - going back to the other DIY thread, I see calculations of 6 to 20Sq inches of radiator per watt. Do you have any advice on this? I see lots of heatsink options on Aliexpress. Makes me wonder if anyone has made a water cooler for their lights to heat their fishtank;)

Many Thanks.
 

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I think 1/16" is too thin. I have 1/4"x36"x2.5" 6063 bars for my LEDs and they get hot to the touch. I think running that many COBs on that thin of a plate won't evenly distribute the heat.

People say that the LEDs can run hotter however I like to keep mine cooled with the thought that it will extend their life.
 

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The one driver per cob is an electrical parameter " partly".
Like I mentioned you can run multiple cobs per driver IF you understand the limitations.
Current divides in parallel.
Soo say you have 1 1000mA driver and 3 parallel cobs hooked to it each only is run at 1/3 of 1000mA.


You gain a little output since the less current the more efficient the cobs run but, obviously not equal to 3 Cobs at 1000mA each.

Next is imbalance. Running multiple cobs/ leds in parallel gas some issues in actual equally sharing as in sometimes they don't and "experts" usually compensate w/ added circuitry.

Third is what happens when one cob dies.
Current us re- shared amongst the remaining
Cobs/diode strings
Example of worst case would be 2 cobs parallel to a 2000mA driver,
While working each parallels cob gets 1000mA. If one fails open remaining one gets all 2000mA possibly killing or damaging the remaining one.
Easy and cheap to fuse each w/ like a 1.25A fuse as a precaution.
 

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Discussion Starter · #7 ·
2.079" extruded alluminum. 3x 60" bars spread out over the width of the tank front to back, then spread out the 9 cobs for each side evenly among the bars directly in the center of each bar front to back.

You'll also want active cooling blowing across the heatsinks.
Great suggestion, I was searching on Aliexpress and was getting frustrated. These will work perfectly, and at a reasonable price. I do find it funny that with this suggestion I would actively cool, within inches of 2 heaters active heating the water. Seems like an opportunity waiting to be designed (not by me ;))
 

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Discussion Starter · #10 ·
has anyone ever tried a custom water loop for cooling these? Use copper water cooling blocks like these connected together. Water comes from tank routes through blocks, and returns to tank. If needed a radiator can be added so you don't boil your fish.
 

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Well the ones I showed were to passively cool Xeon processors and more like 3x3x1"
SNK-P0028P


If I read this right pack of 4 for $36 but I'd check.
Welcome to NextWarehouse.com


Bit overkill but I had fun sliding them around my 55 after I attached legs.
Welcome to NextWarehouse.com


Either their weights off or my scale sucks.. I'd bet on the scale..
Shipping looks to be free..

LDD-hw would thermal glue to the side perfectly.
Small lip and height is below top of fins..
 
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Well the ones I showed were to passively cool Xeon processors and more like 3x3x1"
SNK-P0028P


If I read this right pack of 4 for $36 but I'd check.
Welcome to NextWarehouse.com


Bit overkill but I had fun sliding them around my 55 after I attached legs.
Welcome to NextWarehouse.com


Either their weights off or my scale sucks.. I'd bet on the scale..
Shipping looks to be free..

LDD-hw would thermal glue to the side perfectly.
Small lip and height is below top of fins..
3x3x1 is a really nice dimension for a DIY pendant type, not that tall.
Say there was a fan on top cooling the fins, how many COB's could each handle?
For instance the COB's in this thread, running at 500 mA to extend diode life, could you run just one COB or multiple COB's per heatsink.
 

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3x3x1 is a really nice dimension for a DIY pendant type, not that tall.
Say there was a fan on top cooling the fins, how many COB's could each handle?
For instance the COB's in this thread, running at 500 mA to extend diode life, could you run just one COB or multiple COB's per heatsink.
I've only used 1cob 1hs.
It's fairly easy getting on to hit 110F on a sinble COB..


As an odd side note it was easy (I ran current adj. drivers btw, normally around 500mA) to get really hot heat sinks w/ the SORRA chip.
Think there was a combination of lower conversion to light efficiency of the violet (as opposed to blue) pump and they look to use pure aluminum

plates on their COB's (guess by looking at them) so heating and transfer was quite efficient.


Like I mentioned pretty sure they were rated for 35W so as a guess 2 cobs driven at 500mA would be about 35W..
W/ fans easy w/ 2 cobs.

As much as I dislike them, no denying they cool things quite well.





https://www.edn.com/cooling-high-power-leds-the-four-myths-about-active-vs-passive-methods/


Figure 2 This shows a 2.3″×2.4″×1.4″ fine-pitch extruded heat sink, with a 50 watt Bridgelux LED array. With no air flow, this has a thermal resistance of 4 ° C/W, meaning it can handle only about 10 watts. When a low-speed fan is added to it as shown in the upper view, it exhibits a thermal resistance of only 0.8 ° C/W, increasing its power capability to over 50 watts – a five times improvement! (Photo courtesy of Nutron Mfg Inc.)
why copper you might ask.. because I can't afford diamond.. ;)


https://www.ledinside.com/knowledge...cooling_high_power_led_light_engines_20120308
 
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For fun and since I was "playing" w/ my SORRA light source I thought I'd measure the copper/puck heat.
As expected from before.. at 700mA the heat sink hit 126F (52C).
Face was about 172F(77C) (cob face).

Could go as high as 192F..:eek:

Now you know why I'd never run this part COB at more than 500mA


Soo consider that..
29.7 V(f) at 700mA is 20.79W

Going down to 60% dim approx temp at the cob face dropped to 110F, back remained the same.
 

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Discussion Starter · #17 · (Edited)
Looking back at your example of this Heatsink and Cob installed what size light is that (I am assuming similar to the v10). I wonder if the size of the "chip" is a limiting factor of the heat issue. Xeon chips have a much higher TDP than 35w, but also have a much larger surface area and might have better cooling properties (probably not since Intel). I would think the larger chips v13, v20 would fair better in heat dissipation assuming the same wattage.
 

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Discussion Starter · #18 · (Edited)
So I am leaning towards a Pendant setup again. My wife has some design input as this is our living room, and she does have a better eye for form than I do. I am the function guy. So I did a quick sketchup and was thinking something like this Product White Line Orange Rectangle
.
It would be optimal to use a single COB per pendant. Is the Vesta tunable a viable option ?https://bridgelux.com/sites/default/files/resource_media/Bridgelux%20DS351%20Vesta%20Series%20Tunable%20White%2013mm%20Gen%202%20Array%2020200622%20Rev%20F.pdf

I am assuming I can adjust the height above the tank to get the right coverage, and use the TC421 to adjust color and intensity (dimming). I really would like to passive cool as this is my living room, and our main movie/tv watching area. If these xeon coolers aren't the right one maybe something purposefully built.
Anyone have experience with FrigoDynamics? They have some great looking products but I bet they are really expensive. http://www.frigodynamics.com/images/stories/datenblaetter/OEM_Productguide_Bridgelux_EN.pdf


This is one of the deepest, but most rewarding rabbit holes I have fallen in for a long time, so I thank everyone here for the much needed diversion.
 

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So I am leaning towards a Pendant setup again. My wife has some design input as this is our living room, and she does have a better eye for form than I do. I am the function guy. So I did a quick sketchup and was thinking something like this View attachment 903605 .
It would be optimal to use a single COB per pendant. Is the Vesta tunable a viable option ?https://bridgelux.com/sites/default...ble White 13mm Gen 2 Array 20200622 Rev F.pdf

I am assuming I can adjust the height above the tank to get the right coverage, and use the TC421 to adjust color and intensity (dimming). I really would like to passive cool as this is my living room, and our main movie/tv watching area. If these xeon coolers aren't the right one maybe something purposefully built.
Anyone have experience with FrigoDynamics? They have some great looking products but I bet they are really expensive. http://www.frigodynamics.com/images/stories/datenblaetter/OEM_Productguide_Bridgelux_EN.pdf


This is one of the deepest, but most rewarding rabbit holes I have fallen in for a long time, so I thank everyone here for the much needed diversion.
Bare COBS higher than 5" off the water line start to flood the room more than the tank so, now you are talking bout lenses..
Suggest reflectors, angle will depend on height.


Tune-able COBS are fine.


Gets a bit difficult on how one "tunes" them though..
Maximum Drive Current is maximum combined drive currents between both 2700K and 6500K channels. For example, if 700mA is applied to the 2700K channel, no current may be applied to the 6500K channel of the array. If 350mA is applied to the 2700K channel, then a maximum of 350mA can be applied to the 6500K channel.
Gets a bit tricky if you don't use a specialty 2 channel driver .
you can use 2 350mA drivers to run one COB to keep within the guidelines.
Thing is if you like a "white" (6500k) tank most of the time you "waste" 1/2 the COB.
Using the 350mA as a baseline and what one would run the 6500k at (or a small % of 2700K)
you min # of COBs is 10..to meet the "minimum wattage"
At 350 and ONLY 6500k channel est output is 80% of test sooo 129L/W x .8 x 12W X 10 chips = 12384 Lumens
Of course just a subset of "PAR"

Now much depends on what your preferred look is. From guessing "popular opinion" most prefer a white(or blue white) white over a yellow white so that i why arrays usually run at least 2:1 cool vs warm white
YMMV



You know as a starting point you only need about 120W of leds over that tank.
Adding more COB's at lower drive currents and smaller heatsinks is prob a wash over adding fewer cobs at higher drive current, and larger heat sinks
 

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Discussion Starter · #20 · (Edited)
I was aiming for a lower count of COB's since the Pendant style looks better that way. It was after I posted this previous message, that I looked closer at the data sheet of the Vesta COB's and noticed the Dual inputs, so basically a 1 to 1 ratio since both sides can take 350ma. I assumed there was some type of unicorn magic that made it infinitely flexible.

Would one warm white COB in the center 2 pendant positions with all other outer pendants using cool whites be enough? I figured I can raise those two pendants up to get bit wider coverage and push them harder to make up for any deficiencies if necessary.

As for the height over the tank, I am totally open to keeping pendants as low as necessary, just so that I have adequate coverage with minimal spill over (still talking about a living room here) I am good.

Thanks again for all your expert input. I am totally in uncharted waters for me, so I appreciate the guidance.
 
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