New guy looking for advice

[Rufeo]

Hi I've just recently got into growing, currently using 1 600w HPS but looking to upgrade and change my style altogether. I would like to be able to grow on a racking unit, with two grows stacked on top of each other, so probably about 4ft vertical height maximum between the two levels. Weather or not I do go down that route I would still like to go LED. I've never built an LED before but I can solder, weld etc.

I would like to achieve a very consistent light intensity across my canopy if possible so I guess strips would be best for this? Initially be looking at a 4x2ft grow area although I'm quite flexible on that, I eventually want to go much bigger.

Delving into digikey & mouser I've found a few possibilities from what's in stock but only one seems to stand out at the moment

New Energy SPB1-48F01-3080-00 https://www.digikey.co.uk/product-detai ... ND/8566912
2384lm £5.41 440lm/£ 172lm/w 500mm strip

This seems to be by far the best option from what's in stock in terms of lm/£ while still being decent lm/w.

I want to run them at about 75% power in series, looking for around 1000ppfd so I guess 50w/sqf? So I would need 7 per foot?

Driver would be Meanwell ELG-150-C500A-3Y or ELG-150-C500A 300v 0.5a driver. Which would be 9 in series, which would cover 1.28feet.

Total cost would be 9 strips at £48.67 + driver at around £30 = £78.67. Would cover 1.28 x 2ft or 2.56sq/ft or if you do the maths £30.7/sqft.

Does this all seem about right? Am I heading the right direction?

Thanks Rufe0

[PeteR_1]

Some Calculations;
600W (HPS) * 1.5 PPE = ~ PPF 900 (umol/s)

2 ft x 4 ft = 8 sq ft or ~ 0.8 m2 (sq m)
1000 PPFD * 0.8 m2 = PPF 800 (umol/s) Required Fixture...


50 W/sq ft * 1.5 PPF/w * 8.0 sq ft = 600 PPF
PPF 600 (umol/s) / 0.8 m2 = PPFD 750 (umol/m2/s)


Selected Strips;
2380 Lm * 0.015 PPF/Lm = PPF 35 (umol/s) per Strip
PPF 800 / PPF 35 per Strip = 22.8 Strips

9 strips * PPF 35 per Strip = PPF 315 (umol/s)
PPF 315 / 0.8 m2 = PPFD 393 (umol/m2/s)


Select Driver;
24 Strips * 13.4 Watts per Strip = 321 Watts
HLG-320H-**AB... https://www.meanwell.com/Upload/PDF/HLG ... H-SPEC.PDF


Alternate Strip;
Bridgelux 3000K BXEB-L560mm Gen 2, 2390 Lm, 13.7 Watts, 19.5 Vdc, £3.65 ea... https://www.digikey.co.uk/product-detai ... ND/7907655
LED Driver HLG-320H-**AB... https://www.meanwell.com/Upload/PDF/HLG ... H-SPEC.PDF

LED Strip Sizing Chart... download/file.php?id=4424

[Rufeo]

Ah interesting thanks, so would this chart be accurate according to the generic lumen to ppf conversion factor?

[PeteR_1]

Ah interesting thanks, so would this chart be accurate according to the generic lumen to ppf conversion factor?

ppfd-lux area chart.png

You're welcome.

Close, but NO... There is no such thing as Lux /sq m or Lux / sq ft

PPF - Photosynthetic Photon Flux (umol/s) is equivalent to Lumens (Lm) [times conversion factor]
Lumens (Lm) * PPF/Lm Factor = PPF (umol/s)
Lumens or PPF is a Total ("Volume") output


PPFD - Photosynthetic Photon Flux Density (umol/m2/s) is equivalent to Lux (Lumens/m2) [times conversion factor]
Lux (Lm/m2) * PPF/Lm Factor = PPFD (umol/m2/s)
Lux or PPFD is a spot "Intensity" or "Density" at a given point of measure, Lux can be converted to Foot Candles (FC) or Lumens/sq ft by dividing Lux by 10.763, but few still use FC.

There would only be two (2) columns PPF to Lumens or PPFD to Lux. The Lux column would also (still) be valid if you were measuring your grow area in square feet because its a "Spot" measurement e.g., a Temperature measurement at a Thermometer.

BTW, the "Columns" could be just as easily and accurately labeled;
PPF(PPFD) and Lm(Lm/m2)

[Rufeo]

ok so lets take a step back, what i'm looking for is a simple way to calculate if I want X intensity I need Y l/m2. The lights give you there lumens so with that it would be easy to say I need N number of lights per m2 to get Y lumens or X intensity.

[PeteR_1]

ok so lets take a step back, what i'm looking for is a simple way to calculate if I want X intensity I need Y l/m2. The lights give you there lumens so with that it would be easy to say I need N number of lights per m2 to get Y lumens or X intensity.

Required Intensity multiplied by Area (in square meters) equals Required Fixture Size in PPF or Lumens...
1000 PPFD (or ~ 66667 Lux) * 0.8 m2 (sq m) = 800 PPF (or ~ 53333 Lumens)


Lumens (or PPF) divided by Area (in square feet) equals Lumens (or PPF) per square foot...
53333 Lumens (800 PPF) / 8 sq ft = 6666 Lumens (100 PPF) / sq ft
[Note; 6666 Lm / 2390 Lm per Strip= 2.78 LED Strips]


Fixture Size or Light Output in Lumens or PPF divided by Area (in square meters) equals Intensity or Density
21420 Lumens (or ~ 321 PPF) / 0.8 m2 (sq m) = 26775 Lux (or ~ 401 PPFD)


LED Strip Sizing Chart... download/file.php?id=4424


Edit;
BTW, you can simply multiply the required PPFD by the Area of 0.1 m2 (~ 1 sq ft) if you are looking for the Required Lumens or PPF for a one (1) square foot area.

e.g., 1000 PPFD * 0.1 = 100 PPF or 6666 Lumens

I’m assuming that was the info in the 3rd column of your tables... The Column would be; Lm/1 sq ft or PPF/ 1 sq ft.

[GARDENFIRELED]

I agree the eb strips are the best bang for buck right now