Need you DIY light builders opinions

I created a thread a while back about how much light I could build with tax return money. @dbrn32 was extremely helpful in me building an awesome 400 watt DIY light for around $500 total. I was going to build a second light for my room, but the money had to be used elsewhere at the time. I have since modified the light into 2 to give me a better footprint. I also moved the COBs from 12" separation to 16" for better coverage.

It looks to me like I’m only going to need one more of the 200watt lights to cover the whole area which is 4x5 that I have plants in.
I would like everyone’s honest opinion on what you would do if you were me. The 400 watts of light grows badass plants at more like 320 watts which is what I’m running at now. It seems like 600 watts shouldn’t be enough for 4x5. Especially considering I’m dimming the light by 20%


I don’t have the photon efficacy for a 1216 at 1400ma. But I’ll guess it’s around 2.3 umol/joule. That would give you a ppf of about 460 umols/second per fixture. Three fixtures running at max current would give you a total ppf of about 1380 umols/second.

20 square feet should work out to about 1.86 square meters. Calculating ppfd average 1380/1.86, should put you at a ppfd average of 740 umols/s/m2.

Looks good to me homie.


That’s crazy that I can run 20 sq ft at around 560 watts. That’s less than 30watts/sq ft. Hell, I couldn’t get tight buds with the Amazon lights at 875 watts for the same area. Also a lot less heat.

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Ya, the other fixtures just aren’t as good at making light. You could probably run a little more, but nothing like a 4th fixture or anything. I would go with the third fixture and run a grow or two, I think you’ll be pretty happy with results. But if you feel like it’s a little weak after that, we’ll look at dropping some strips between your fixtures or something that jives well with what you already have. 100 watts of strips would move ppfd to something like 875, and you’re pushing point of diminishing returns there.