So i wanted to post my fav light i ever built here as my client just harvested with it:
Its meant for a small auto tent but got enough light to run a a m2.
Dimensions are 70x70cm or 28" each side approx for a 80cm tent. It replaced a 400w hps.
Its based on bridgelux vesta strips: dual 90cri channels, one for 5000k one for 2700k and you get around 3800k if you run both at the same time. The photo above is with both channels, not sure why it has such an intense warm white look. Each strip is almost 200 diodes so with 14 strips its almost 2800 white diodes and 22 red monos: 630/660nm spread.
The reason i like this light so much other than my undying love of vestas is the amount of control it allows with just a few simple measures. First: spread control: theres 2 circuits, one for all the strips is the middle and one for the strips running along the edges. This means you can control the hotspot or boost the sides for more even spread. Here we see the centre circuit only:
Again this is both channels but the white balance makes it look more cold. Also all the cabling was tidied before delivery.
On the centre circuit i opted to add some reds, since all strips are 24-25V it gives us an approx 25% extra reds on the centre circuit (12.5 of total wattage) spread over both 630 and 660. Keen eyes can see the difference, 630 slightly more orangy.
For drivers i used xlg-150m : voltages are around 100V so still not dangerously high, the M version is constant power so its easy to driver watch and the light does 300w in total, although seems like 100w is enough for my clients space.
In order to get spectrum control i added some switches on each circuit:,
So driver + to right side wago splits the current in 2. White switch sends light thru the CW circuit, black to the WW circuit. Same again for the 2 circuits so you can mix and match spectrums between centre and perifery.
The design of the light wasnt really clear at first i already had the strips but during lock down i got this ambitious idea.
What i really like is the amount of control you get with this light, it really puts the grower in the driving seat for full cycle growing. Seedlings stay nice and bushy under cold white and under pure warm white in flower its hard to keep up with the plants. All its missing is some uv and and far red on separate channels.
Stats: the driver runs the strips at 750mA each at full, which is about 2.4ppf/w, vesta gen1 isnt all that efficient. But this run each driver was running at about 50w so each strip around 250mA which is about 2.6-2.7ppf/w. If we then factor in that a big part of the grow this 250mA is shared by 2 channels this number goes up even more but i think its pointless to make efficiency estimates anymore. If my memory and calulations arent messed up that would mean running each diode at around 10mA or less than a 6th of common nominal current of 65mA and less than a 10th of what people usually run their lm301bs.
All values based around tekniks vesta tests here on site.
These are some pre harvest pics at 100w for approx 7 square foot: