Anecdotally the advice seems to be to use lighting with a CCT of 6500K, although I've been unable to find any academic material to back this up. I presume the blue bias is to prevent stretching/etiolation which is common with succulents. As 6500K strips seem to be hard to acquire in the UK, I'll be going with the nearest available CCT of 5000K.
I'm happy to pay a bit more for the build to get something efficient and I also want to run the strips relatively softly to avoid having to buy serious heatsinks which add to the cost faster than just adding more strips. I'm looking at the EB Gen 3 Slim strips, available from Digi-Key - https://www.digikey.co.uk/product-detai ... =367115794
Requirements:
- Dimensions to light: 60cm x 64cm = ~0.4m^2.
- Spectrum: 5000K @ 80 CRI
- Target PPFD: 350/400(source: https://herebutnot.com/light-recommenda ... useplants/)
- Dimming support via Pot/PWM
- "1ft" strips - I'm looking at the 340mm ("1ft") strips to give me the freedom to change the shape of the array later if I desire.
- Voltage under 60V SELV limit
- Minimal (aluminium angle mount) heatsinking
- Ability to add more strips
@ 10.9V / 700mA / 1530 lm / 200lm/W
To get to the 10 unit price break on Digi-Key I can run an additional two strips and run all the strips at a softer 500mW for the same PPFD.60 * 64 = 3840 / 10000 = 0.38 m2 (~ 0.38 sq m). Rounded up = 0.4m2
0.4 m2 * 400 (PPFD per sq m; High-Light Houseplants (Tropical Succulents like Christmas Cactus, Philodendrons, Monstera)) = 160 PPF (per 0.4 sq m)
For Bridgelux I use the Generic Conversion Factors... viewtopic.php?f=15&t=5756
Generic for White PC LEDS - Lumens to PPF (PPF/Lm) Factor (cF):
0.014 = 5000K 80 CRI Cool
0.015 = 4000K 80 CRI Neutral
0.016 = 3000K 80 CRI Warm
200 Lm/W * 0.014 = 2.8 PPE
160 PPF / 2.8 PPE = 58 Watts
1530 Lm * 0.014 PPF/Lm (cF) = ~21.4 PPF per Strip
160 PPF / ~ 21.4 PPF per Strip = 7.5 (~ 8) Total Strips
@10.63V / 500mW / 1147lm / 215lm/W
Wired 2S / 5P: 21.36V / 2500mA215 Lm/W * 0.014 = 3.01 PPE
160 PPF / 3.01 PPE = 54 Watts
1147 Lm * 0.014 PPF/Lm (cF) = ~16 PPF per Strip
160 PPF / ~ 16 PPF per Strip = 10 Total Strips
For a driver I think this is what I need - HLG-120H-24AB. The 100W AB version wasn't available anywhere, hence going for the larger 120W.
- Max power = 120W
- Constant current region: 12 -24V
- Current adjustable range 2.5A - 5A
- 10 -> 100% dimming
- Efficiency @ 53.4W / 44.5% load = 91%
I'd also appreciate if anyone has a recommended UK source for the aluminium angles?
Thanks!