Would be interested in some opinions currently running 4x 132 v1 boards off a lrs-350-36 with pwm dimmer wired in so full dimming from 100% down to about 10% than click off. in a 2x4 tent. boards spread out pretty much full width coverage so height over the canopy isn't an issue for spread. currently running three auto. 2 at 39 days and flowering and a youngster still at 15 days. Currently running the lights 16-17" over the canopy at full max power. plants are loving it. Saw a number of posts lately from @Tbone Shuffle about he is running his bloom tent with all his lights running dimmed all or most way down. Never saw Tbone post anything I'd ever question so not starting now was curious if running the lights dimmed but lower is more beneficial than higher and more intense. I think I'm past the stretch stage on the two big ones so it's just flower development and waiting for the end. I realize the electrical efficiency gains would be there but wondering if there was actual plant gains as well.
Not sure about the case in question but I buy my lights with more power than I can use in my space then run them at 50-60% capacity this helps me control temps. No matter how you achieve it up high and turned up or close and dimmed you want to get an even spread of 50000-60000 lux. 800-900 ppfd. As close to these numbers as you can get some plants will not take this much light. I start turning it up in veg getting them used to more and more light as I've found it better to change light intensity slowly rather than all at once .
with the 132 boards, heat is rarely an issue. I see that issue with others, and with my 288 boards it can be, but in this case it isn't. not an issue I'm concerned about in this particular inquiry. I do understand what you mean though. if temps WERE an issue than dimming is definitely a feasible option to reduce heat
Take your lux and divide by 64 and it’ll give you your PPFD doesn’t matter how dim or bright they are if your PPFD is in range Sent from my iPhone using Grasscity Forum
I can’t speak for Tbone, but I believe he has a variety of lights in his tent which is why he runs them so low. Again, I believe he has well over 1000 actual watts pumping in that bad boy, so he dims them to about 750 I think, or near there.
The only way you can run them all the way dimmed and still have plenty of light in bloom is if you run too many boards for your space. I'm running two 288v2's on an HLG-320h-c2800a, two qb304's on an HLG-240h-c1050a two qb96 elites on an HLG-320h-54a and a qb18 red strip on an HLG-40h-24a. So I have plenty of potential power in there. Actually more then enough for a 5x5 if I wanted and it's in a 4x4. The only one I'm not running dimmed is the red strip. It allows me to get away with only about 12" light distance because my plant is so tall and not burn them. If I turned up the power the light levels would be too high at 12"
I can take some fresh pics in a few hours. It's been a while. It definitely has filled in. I need to trim it one final time.
As for what would be more beneficial for the plants, idk, can you achieve a deeper canopy penetration higher or lower? Maybe take the meter and take some under canopy readings! See which way gets more light to the lowers.
If I could I would run a little more light distance and turn them up a bit but I'm actually getting about the same light intensity I did last crop just at a closer distance with less power. I guess maybe at the expense of penetration but maybe not. The leds also run more efficient the more they are dimmed.
thanks all. sounds like the it was just a matter of over-coverage - more than needed so reduced. Understand! was just wondering if there was another issue I missed thanks all
I currently have my qb132v's 3500k on a hlg-320h-2100a at 106watts. I started the lights at 60" and 110ppfd for when they where seedlings. At day 9 I dropped it down to 45" for 160ppfd. Today, day 23 I dropped it to 20" for 240ppdf and still at only 106 watts. Plant in soil had bottom 2 nodes removed and topped 5th node for quad lining. DWC plant has had bottom 2 nodes removed and I will remove top the 5th in a day or 2.