I’ve got got 3 little 2’x2′ spaces set up in the basement, and each of them has a single Quantum Board in it. The first space on the left is a 4000K 80 CRI board, the second in the middle is a 3000K 80 CRI board, and the third is a 3000K 90 CRI board. Each of the 3 spaces has 4 jalapeno plants in it from the same pack of seeds, and I’m feeding all 12 plants the same amount of nutrients from the same batch, at the same time. All 3 boards are getting the same amount of power and are hung at the same height.
From Instagram live: Taking another run at overpowering a QB288, this time with an HLG-600H-54 and a boost converter. Sorry for the crappy quality and vertical video – the format it saves to isn’t great for watching on PC.
This is a subject I touched on in an earlier video where I tried to run about 175 volts worth of LED (5 COBs) off of a driver only rated for 143 volts max. The result in that test was that the driver maintained its full voltage (~143v), but put out next to nothing for current. What I set out to test this time was what would happen if you were trying to pull just a handful of volts more than the driver was rated for, as opposed to trying to pull 30+ more than rated. By adding resistors in series with my 4 COB lights, I was able to slowly increase the voltage drop of my circuit to meet and exceed the max rating of my driver and see how it reacted.
In a previous post, I built a pair of space buckets to start my 3000K and 5000K peppers in. The buckets worked excellently – they made it really easy to control temperature, humidity and airflow, and they got my peppers off to a great start. One of the best features of the buckets was how much light made it from the COB down to the plant canopy – especially after the walls were painted white. Off of a single Vero 18 COB, at the very bottom of the bucket I was getting a PPFD of 500 µMol/m2/S and at 12″ away from the COB, I was getting 1,100 µMol/m2/S. Having seen how well these worked, earlier this week, I set out to test out another popular “Space” device: the mighty Space Tote. Continue reading
As I’m getting my shit together for this build, I’ve been testing a few different things along the way. This weekend, I assembled my strips into 2 lights that would be similar to the Horticulture Lighting Group’s QB288 boards. Each of the lights is comprised of 12 strips with each strip containing 24 diodes, for a total of 288 diodes per light. For now, I just taped all the strips together, then fastened each “light” to a piece of wood to be able to hang them easier.
In this video, we’ll have a look at what happens when the sum of your COB voltage drop in a circuit is below the minimum constant current region voltage of your driver, as well as what happens when it’s above the maximum constant current region voltage of your driver.
In my previous test, I ran a couple of Vero 18 COBs at their typical rated current to see if I could get either of them to go into thermal runaway. Over the 4 hours I tested them, each of the COBs ended up pulling an additional ~50mA each than what they started at, but stabilized at this level. Curious to see if I could get one of my COBs to go thermal, I decided to take another stab at this and hit a couple different chips with considerably higher currents than they’d normally be run at.
After playing with my new HLG-100H-36A constant voltage driver for awhile, I conducted a little experiment this weekend to see if I could get either of my Vero 18 COBs to go into thermal runaway. Thermal runaway can happen in constant voltage systems where the current is allowed to vary, while the voltage is held steady. As the COB LEDs heat up, their properties change, and this causes them to draw more current, thereby heating them up further and drawing even more current. Eventually, the LED can destroy itself due to this cycle of drawing more current and heating.
Quite often, you’ll see recommendations to add a resistor in series with your LED if you’re using a constant voltage driver. I wanted to see if I could get away with skipping these resistors and simply running my COBs hooked up directly to the driver.
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