Stereodude
Not really a
Does your controller / driver support dimming?
48V DC LED wiring for a new build; XM-Ls, etc.
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jtr1962
Storage? I am Storage!
I'm going to guess that the dimming input on the 2100 mA driver needs to have a voltage applied. The driver has 0 to 10 V dimming, and the dimming input may default to 0 volts when open.
jtr1962
Storage? I am Storage!
I'll send you a PM when you're ready to order the drivers so we can exchange info. I should also be able to recommend a transformer, although the one Dave ordered looks pretty good. For 8 LEDs you'll probably need to go higher than 24V if they're in series (or you could just do 2 parallel strings of 4).
ddrueding
Fixture
Found the issue. The power supply I'm using isn't. It is just a transformer outputting 12v AC. That won't work. More coming, hopefully tonight.
Do you mean the 60W Dimmable Power Supply / Driver combo he's using? I'm not sure how that applies, since it's apparently an all-purpose driver, is constant-voltage rather than constant current, and, according to his recent post, is apparently not even a power-supply at all, somehow? (false advertisement?) Or did I miss another transformer / power-supply recommendation he made?
I could do that; put the control in the middle and run the two strings in either direction, rather than starting at one end. When I was looking at some circuits more closely a few weeks ago, I remember thinking that going parallel added some complexity to the driver circuit, but perhaps I'm wrong, and even if right, perhaps it doesn't matter since I'm not going to try to build my own driver. My objectives are efficiency, simplicity, reasonable color, and appropriate brightness. If a parallel arrangement doesn't compromise efficiency or simplicity, then I'll do it. Otherwise I might have another idea to keep things serial.
Very interested in knowing the outcome here....
ddrueding
Fixture
Nope, that is the one. And before we mark it as a failure, you should know that I'm not very clever on this kind of thing. Every test looks like it should work, so it might be a great product and I'm just missing something.
I just haven't had the time to spend on it lately. Perhaps I'll have a chance later this weekend.
AC alternatives
Ok, now I've been investigating home-brewed LED solutions whose power source is ultimately 120V house line for awhile, on and off. The “typical” approach, and the only one I considered when I started this thread, is to use a driver circuit to generate constant-current power. I understand that LEDs' life-expectancy requires that the power-source be constant-current. But you can find A/C ckts like this: http://electroschematics.com/3623/ac-powered-white-led-lamp/ - which generally involve a rectifier. So, the question is: do A/C line-powered circuits like these severely reduce the life-expectancy of the LEDs? If not, it is certainly an attractive alternative to the very expensive off-the-shelf options, and understandably so, for simplicity. I'm not positive, but, considering all that is necessary from line-power to LED, whether you go with an approach like that or a more conventional AC-DC driver approach, it might be less expensive to consider the line-power AC approach. But then one would guess that line-power off-the-shelf options would exist; perhaps it’s hard to UL-list such?
Ok, now I've been investigating home-brewed LED solutions whose power source is ultimately 120V house line for awhile, on and off. The “typical” approach, and the only one I considered when I started this thread, is to use a driver circuit to generate constant-current power. I understand that LEDs' life-expectancy requires that the power-source be constant-current. But you can find A/C ckts like this: http://electroschematics.com/3623/ac-powered-white-led-lamp/ - which generally involve a rectifier. So, the question is: do A/C line-powered circuits like these severely reduce the life-expectancy of the LEDs? If not, it is certainly an attractive alternative to the very expensive off-the-shelf options, and understandably so, for simplicity. I'm not positive, but, considering all that is necessary from line-power to LED, whether you go with an approach like that or a more conventional AC-DC driver approach, it might be less expensive to consider the line-power AC approach. But then one would guess that line-power off-the-shelf options would exist; perhaps it’s hard to UL-list such?