Bro, you’re a blessing. My gut said to turn them down at my friends place. Which I’ve done already. I’ll do the same with the one at my place until I have a replacement.
My heatsinks get around 60 celcius without active cooling.
You wanna keep your diodes junction temps under 50C for them to last and not lose intensity. Under 50C they last for years.
You beat me to the point
Yeah, when I noticed they ran hot, i added a fan. That made such a difference.You wanna keep your diodes junction temps under 50C for them to last and not lose intensity. Under 50C they last for years.
You beat me to the point
The last time I looked Cobkits is down to 27 QB 288 V1 in 5000k color temperature.
horticulturelightinggroup.com
What you've got there, I suspect, is a case of thermal ruanaway from mismatched voltage bins on the boards. What happens is the voltage requirements of some of the LEDs in one or more strings (which are wired in series) are lower than the others, and so they start to pull a higher current. As they pull more current, they heat up and so the voltage requirements fall and they start to draw even more current. Eventually some of the LEDs fail in the closed circuit position and so the voltage requirements of that string fall again and draws even more current – that's why it's called "runaway", as it's a self-perpetuating cycle. And that's why you see the strings with the failed LEDs shining brighter than the others.
I concur. You get what you pay for. Let's hope you get some new boards. But you should also ask them if they voltage bin. Chinese knock-off companies are notorious for claiming "top bin" this and "top bin" that, but it's usually bullshit. Oftentimes they're not even Samsung chips. I can't tell from your photos as they're too small.What you've got there, I suspect, is a case of thermal ruanaway from mismatched voltage bins on the boards. What happens is the voltage requirements of some of the LEDs in one or more strings (which are wired in series) are lower than the others, and so they start to pull a higher current. As they pull more current, they heat up and so the voltage requirements fall and they start to draw even more current. Eventually some of the LEDs fail in the closed circuit position and so the voltage requirements of that string fall again and draws even more current – that's why it's called "runaway", as it's a self-perpetuating cycle. And that's why you see the strings with the failed LEDs shining brighter than the others.
To keep prices down, I suspect the Chinese knock-off board manufacturers are not ordering matched votlage bins for their boards and so the voltage requirements of individual LEDs could vary by as much as 0.3V, which is enough to cause what you're seeing. These board don't run ballast resistors to even out the current, but rather rely on the high number of diodes in each string to balance out the voltage of each string.
We don't use ballast resistors in our boards, either, but we match our voltage bins to 0.1V for the entire run of boards – and we pay a premium for it, too. There will still be very slight variances in voltage requirements for each string, but it is not enough to cause thermal runaway like your boards.
Sorry to hear. I hope Kingbrite comes to the party for you. I'm sure they know what the problem is, but don't expect them to admit it
Led-tech.de also have what appears to be hlg quality boards but its a slightly different design. Buut at least its within eu
Luckily boards only tend to be quite cheap. Id just bite the bullet and get new boards. Maybe theyll give a bit off for trouble/corona