I once lit a joint with a 600w HPS.
I used to grow under 2x600w HPS. Then I stopped growing for a few years. I came back to growing in April 2020 when the Pandemic meant I couldn't get any weed. So I pulled out my old HPS lights and they wouldn't work. So I bought some cheap COB LEDs on Amazon. They worked but the weed was always a bit light and fluffy. I couldn't get the results I used to get under HPS, but I wasn't chasing my arse trying to keep everything cool either.
My mate is a grower and a bit of an electronics guru too. He showed me some lights he had built using bits he bought on AliExpress. Samsung LM301H boards and Meanwell drivers. Basically he had built a clone of a Mars Hydro TS1000, at a fraction of the price. So I had him build me 4 of them.
So I am now running 4x150w in a 4x4 and the results are impressive. Yes I have to run a little 80w greenhouse heater 24/7, but that actually makes little difference to the cost. I will never go back to HPS.
The only niggle I have had is getting the temps and ventilation right. If I use my big RVK fans the temp drops too much. So I have some extra desk fans to keep the air moving and a small tube heater, it works. As it gets warmer I am going to invest in a modern AC Infinity fan and control it with some Zigbee temp/humidity sensors and some smart switches.
These are mine at week 5 of 12/12...
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I am not one for taking pics of my grow, the first time I have ever posted a pic online, I took it a couple of weeks ago . It doesn't give you much sense of scale, but the colas are now tight as can be and the frost/resin production is awesome. Not the most impressive grow ever, but I am very pleased with results. Especially as I have never grown under these lights before and I have changed the pots/medium I am using.