Introduction
Last year we bought ourselfs some 2nd hand IKEA grow stuff for in the house:
KRYDDA + VÄXER
The growlight has the following specs:
Colortemp.: 4200 K
Light: 900 lumen
Power: 16 W
Ppfd: 100 μmol/m²/s
The area of the KRYDDA is 57x38 cm: 0,21 m²
Ppf: ~23 μmol/s
lm/W: 56 (this includes the drivers inefficiency, so the light is a little more efficient)
The lettuce, basilicum, seedlings for the greenhouse etc. are flourishing underneath it, so last week my girlfriend said she might want some extra light. Ofc. I mentioned that a DIY build is more fun and gives better lm/W.
I said I would make something similar 3x aluminium bar of ~50cm/1,65" buy a driver, some small COB Vero 10 SE 4 on each bar. and run them on ~300 mA.
Then i thought, i can put 2x Vero 18 SE on each bar, run them at ~600 mA. The COBs are more efficient and it's possible to increase current if situation asks for it.
So I was wanted to find the Right Heat Sink for my COB LED, so I started reading the "How to Find the Right Heat Sink for Your COB LED" part of this side.
So I found the formula:
Rh-a = (Tc – Ta)/Pth – RTIM
Vero 18 B run at 600 mA gives ~19,6W -> 20W.
Heating Coefficient H 0,75
Pth = 15 W
Ambient Air (Ta)= 25°C
Maximum Case Temperature (Tc)= 85°C
Thermal Interface Material Resistance (RTIM) = .05°C/W
After my calculations:
Rh-a = (Tc – Ta)/Pth – RTIM
Rh-a = (85 – 25)/15 – 0.05
Rh-a = 3.95 °C/W
If i might want to increase lightning later so i'm doing the calculations for 30W as well: Rh-a = 2.62 °C/W
Next step I went to the magical internet to find myself a suitable, cheap piece of aluminium to cool them passive. And that is were the problems start. Online I find pieces like:
https://www.tme.eu/gb/details/rad-a5723 ... stonecold/ Thermal resistance 2.3K/W
https://www.tme.eu/gb/details/rad-p3698 ... stonecold/ Thermal resistance 2.3K/W
They're both <2.6 °C/W so should work fine.
Because I heard of the rule of the thumb, 17 sq.in for each hW that ment I should come up with a piece with 23x17=391 sq.in, or 2522 cm².
I'll roughly calculate the surface area of the heatsinks and find that they're only 280 cm² and 606 cm². By far not around the 2500 cm².
So i'm guessing those numbers are for forced convection and I have to go for a bar like this:
https://www.tme.eu/gb/details/rad-a5724 ... stonecold/
Now I read some quantum boards/mid-power LEDs getting even higher lm/W then the COBs i'm focusing on now and you can save on the heatsinks. (Still have to dispatch a lot of heat right?) Now I was wondering were to begin investing in these LED strips, and is it a better solution to go for instead of a few Vero 18 SE?
Note:
1. I already bought myself a ELG-150-36A.
2. looking for a light for seedlings/cutlings etc. might want to grow a few peppers indoors too later.
3. Please take a note on the budget, don't want to spend more then €120-130, Driver costs me ~€20, so have like €100 left for lights and heatsink.
Questions..
1. The IKEA light only has a ppf of 23 and the plants love it. Do all plants benefit from the extra ppf or could they burn?
2. Anyone has an alternative heatsink i could use for this? (heatsink is 50% of the total cost of the lamp)
3. Do those mid-power LED COBs have less heat to dispatch then the Vero 18 SE?
4. Were to start if I want to buy a low power LED strip?
Low power setup / heatsink dimentions
It might be tough to find a mid-power board to fit the 36v driver. It might be impossible with your budget. Give these a look:
https://www.digikey.com/product-detail/ ... ND/5358457
https://www.digikey.com/product-detail/ ... ND/4966153
The Samsung is probably the better bet, but you should do the math to see if it would be cheaper to sell the driver and get a 20v driver so you can use the cheaper Bridgelux EB strips:
https://www.digikey.com/product-detail/ ... ND/7907664
LG has some builds set up for these strips.
COBs are a different story. You have all kinds of options at 36v. You could run these with that driver and mount them to aluminum bar or channel and adhere heatsinks as needed:
https://www.ebay.com/itm/5x-CITIZEN-58- ... 2366266276
https://www.digikey.com/product-detail/ ... ND/5358457
https://www.digikey.com/product-detail/ ... ND/4966153
The Samsung is probably the better bet, but you should do the math to see if it would be cheaper to sell the driver and get a 20v driver so you can use the cheaper Bridgelux EB strips:
https://www.digikey.com/product-detail/ ... ND/7907664
LG has some builds set up for these strips.
COBs are a different story. You have all kinds of options at 36v. You could run these with that driver and mount them to aluminum bar or channel and adhere heatsinks as needed:
https://www.ebay.com/itm/5x-CITIZEN-58- ... 2366266276
The new QB132 from HLG is also a 36V board and doesn't require a sink.
Want to Support the Site?
Use this Amazon referral link and any purchase you make within 24 hrs will earn LEDgardener a commission at no cost to you!
Use this Amazon referral link and any purchase you make within 24 hrs will earn LEDgardener a commission at no cost to you!
This is actually exactly what I was looking for. Efficient, nice size, 22,5 x 30cm, not to expensive, 4 of them for ~$130 (+$50 VAT) that makes ~€35 each. When saving bucks from heatsink and frame and very clean and easy to mount.
I already bought myself 6x VERO 18 SE (Arrow) matching my driver (ELG-150-36A) with heatsinks from Kingbrite. Might just finish that light, sell it and go for some of these qb!
Nice. I’m sure you’ll love the Veros too though.
Want to Support the Site?
Use this Amazon referral link and any purchase you make within 24 hrs will earn LEDgardener a commission at no cost to you!
Use this Amazon referral link and any purchase you make within 24 hrs will earn LEDgardener a commission at no cost to you!