Lighting 39V 2.1A COBs good/cheapish drivers?

[Rapha El]

Photosynthetically active radiation

Usually tested with a meter but it not sure the height these were tested from.

Basically it's all the light that falls within the400-700nm range.

he do you have the par numbers for 3000k, 3500k and 4000k of say a 1212?

While I'm waiting for parts I've been planning the mounting and cooling of the things. I'm gonna be using some old socket 775 server coolers; Passively they can do about 20 watts with an air current in the "room" actively they'll be able to dissipate about 70 watts with the fans I picked.

The mounting itself will be a tad unconventional. I'm gonna take the holders and sandwich them between two pieces of metal (the copper piece from the cooler and the steel piece that's being cut (bottom right corner of the image)). I don't wanna drill and/or tap the heatsink and that's gonna allow me to not do that.

Eventually I want the fans to each have their own little stepdown converter so I can just plug and play the lights with some molex connectors but the way I layed out my cobs and driver I'm within 2 volts of the max current the driver can push sooo none of that for now.

I'm also thinking about putting some bimetal switches in my setup. One to open at 90c so the cobs don't burn and one to close at 45c for the fans to kick in.

What do you think would be the best temp for the fans to spin up?

edit: just got my cobs.. they're so tiiiiny lol

 

[BigSm0]

I don't have the different par numbers sorry. I tell you that won't be laughing of it's size when you plug it in.

 

[2Stoned2Care]

I tell you that won't be laughing of it's size when you plug it in.

Yeah i was seeing 4 bright ufo's for over an hour when i turned mine on

 

[KonopCh]

View attachment 670261

Thanks to cobkits.com bobby_g is a real classy guy with to much knowledge when it comes to cobs. Same goes for robin at northern grow lights. This is why I'm always recommending these guys. I have accounts through a few distributers but really like to support the guys who provide all this info and make DIY possible.

These aren't correct E numbers. I have seen on another forum 5-9% lower. Same CRI, same colour, same wattage, Vf etc... But not E.

 

[Rapha El]

These aren't correct E numbers. I have seen on another forum 5-9% lower. Same CRI, same colour, same wattage, Vf etc... But not E.

8/9% sounds like the difference between active and passive cooling to me. You can loose up to 25% if you get too hot,it would appear by looking at the spec sheets

 

[BigSm0]

They are all from the same guy. I think some were tested with math and some were tested in real life.

 

[KonopCh]

I've got spec for Tc = 50°C.

 

[Rapha El]

Do you hear that?

That's the sound of all the pieces shipping for the 'work in progress' lights being built

 

[Rapha El]

I got everything but for the mounting plates here so today I'll start tinning and soldering so I can do a quick test and make sure everything works.

The heatsinks and fans are mounted up, tested them and they are quiet. And I mean I have to stick my ear right to it to even hear them running. Brilliant, I love it. Not that it makes a difference with my turbine of an extraction fan but if I mod that in future I'll already be set on the sound levels for the lights.

Photos will come later but for now I can tell you that a push/pull configuration works a charm with these low static pressure fans.

 

[Rapha El]

I had to confirm they were all working.. do you know how hard it is to see 4 dots of light when everything is light?!
god damn they are bright, i see spots everywhere


Edit: Almost an hour later and I'm still seeing spots so I get what @BigSm0 is talking about. These things are about as bit as my thumb nail but ooooh my god are they bright.

Now I just have to widen tha cable channels in the holders so they can accommodate my cables (I'm using .75mm² ones and the cheap cover type holders. The soldering went surprisingly well and I only smudged flux over half the cobs