Those have to be passive-loss drivers. Any switching regulator has to have an inductor that is going to take up at least one cubic inch. But you could make a very efficient 120 VAC COB, just by having 165 DC volts across the LED string and 5 DC volts or so across the passive-loss element. An 82.5 watt COB would draw just 1/2 amp, and the passive loss element (resistor or transistor) would have to dissipate 2.5 watts, so it would be about 97% efficient. But anytime the mains AC dropped below 117 volts the light would go out!
That’s really the tradeoff you have to make with passive-loss. You want it to work even if the power line drops to 105 volts and if there is a surge it can be as high as 136 volts. So you have to handle that wide range by burning off the excess over 105 volts, so immediately you are at about 87% efficiency and it gets worse when your power line runs higher than 120 VAC.
To handle this input line variation, we can use a switcher that always makes just enough output to drive the COB but that switcher has to have at least one MOSFET and a fancy diode or two MOSFETs, two big capacitors, and an inductor. It gets expensive!
Right! It does. I think these things have 5 drivers at 100ma each for each diode string. They have a 6.8ohm limiting resistor if they are the same design as the 50watt floodlight COB. I think they are.
I will have to get get back to you on that. I took my meter home to do temp tests in the flower room. I build my lights at a friend’s shop and there’s no meter here.
Well that would be cool. I don’t mean to be an extreme pessimist lol, just don’t want you unnecessarily tearing stuff up either.
I’m almost certain that they would advertise a dimming circuit if they intended it to be there. It’s just as easy that those were installed to change the parallel to series string ratio on the high voltage diode pack to create the low voltage cob. Or, any of another number of explanations.
They don’t advertise nothing on these lights except the light spectrum. I’ve been trying to find out about them for months. The Chinese site I use has a lot of things that they “sell” for free. You just pay $3 each shipping. They only have a dab of solder on pins 7 and 17 like wires are supposed to be put there. The only other place they do that is the AC input pins. If these are the same as the floodlight COB, and they are only using 1/2 of the driver chip. I’ll find out soon enough.
Yet to personally try this, but I believe you can find a few examples of these being used to flower plants on YouTube. If I was on the cheap, I’d probably give them a go. Maybe enough room in budget to grab a daylight spectrum for vegging plants too.
We both know flowering is going to take serious light if we want serious yield. I know you’re not a fan of side lights. I’m wondering if they might help if you want to do almost no pruning like I want to do this time. My plants look really good and I wonder if the light from a bunch of 12watt led spots might make the lower parts grow decent colas. I have 2 of those 6 light vanity fixtures for $5 each from habitat for humanity store. That’s only 144 watts. I already have the bulbs.
I don’t think it would hurt. Not sure if they would be huge, but light will certainly help them develop more.
I’m not exactly against side lighting, more investing money in it to offset weak overhead lighting. In that situation I would be a much bigger fan of replacing the overhead lighting, and then moving the lower performing light to some sort of secondary function like side lighting. If that makes sense?
In your situation, throwing some stuff you already have in there to assist, I’m not really against at all. Same thing with those micro type grows. Space buckets, pc case, or anything where the overhead space is limited. I like some additional intensity there, even if you have to spend a few bucks.
In situations where the overhead lighting isn’t up to par for the square footage, I’d much rather see members work on that or save the cash for a time that they can. Instead of wasting money on temporary band-aids that will eventually still require more spending in the future.
You can spend less upfront, and get lower efficiency lights. Then you probably spend more on electricity during the first grow than you would have to get better lights, And then you spend a lot on electricity for your second grow, for your third, etc. It makes sense to try and find something near the cutting edge, but not AT the cutting edge. That’s always too expensive. You want technology that is proven and in mass production.
Mean Well drivers and Vero29s are one of those good combinations. I’m sure there are other COBs like Cree and other drivers that are just as good. But there are a lot of bad LEDs out there, that won’t do a very good job of growing or send your electric bill soaring.
For just a 3x3 tent, you need about 315 real watts of LEDs, fluorescents, or HID. If you have an average driver or ballast, that translates to 370 watts from the wall outlet. If you have a lousy driver you might need 600 watts!
I just finished taking down my big rack of lights, pulleys, and ropes and replacing that with adjustable shelves on each side of my grow chamber. Each side has a little 36" wide by 4" deep shelf. Resting on the shelves are two 2x2s that each go to the other side’s shelf. My lights rest on top of the 2x2s. So I can easily move the lights together to put more light in a small area or spread them apart to light a bigger area. I can easily adjust the shelf height just by moving the shelf brackets in the pilaster strip.
It’s probably an input then. Controller chips are often programmed to do one thing if a particular pin is open, another if it’s shorted to ground or positive. I wouldn’t mess with it because it could be an operating mode change, like higher current that would damage some parts. CMOS inputs have very high resistance.
