Minimalistic multichip DIY LED build

[mr.wilson]

This is good info. I just got done soldering three of the 60W combos about thirty minutes ago. I contemplated soldering to the pads on the frame block but I was not sure how to apply enough heat there. (I'm not a pro)

Maybe I should give it a try.

Soldering to the block is easy. Use all-in-one solder with flux and don't let the iron get too hot. Remember to double check polarity before you solder.

 

[mr.wilson]

Here's a 100w multichip I made a year ago. I had aluminum rings made to cover the heat sink fins and fan, as well as an aluminum chip & lens holder. Zalman discontinued the CPU cooler within a few months

 

[noplay180]

Nice

 

[hillscp]

Soldering to the block is easy. Use all-in-one solder with flux and don't let the iron get too hot. Remember to double check polarity before you solder.

I'll try it again tomorrow. I'm using 16g wire. Maybe I should be using 18? The wire was higher than the frame so it kept the lens cover from going all the way down.

 

[hillscp]

hillscp i am going to try 3m liquid tape to insulate i did not know you could connect to the frame pads

I checked continuity. The frame pads are separate from each other and part of the block pads.

 

[mr.wilson]

You can use silicone to insulate and resist moisture.

 

[hillscp]

Do you think I could use 18G wire? I have an HLG-80-36B PS

 

[BeanAnimal]

18 AWG is rated for 7A

200W @ 36V = 5.5A

You sould be fine

 

[mr.wilson]

I use 18 solid wire with heat resistant insulation, but the heat resistance isn't necessary. Lassef posted some sizes recently.

 

[hillscp]

Thanks, that will make it easier

 

[BeanAnimal]

Teflon insulation is nice, as it doesn't melt and deform close to the solder joint.

How are the commercial fixtures attaching the multi-chips to the electronics?

 

[Mike31154]

This is good info. I just got done soldering three of the 60W combos about thirty minutes ago. I contemplated soldering to the pads on the frame block but I was not sure how to apply enough heat there. (I'm not a pro)

Maybe I should give it a try.

If the arrows on your photo are meant to show the 'pads' you are contemplating soldering wires to, I would caution against that. It's difficult to tell from the picture but I don't think those are actually solder pads, they appear to be part of the base of the chip. Could end up being a dead short between + & -. Besides, you would be applying heat to a very tight spot, closer to the LED chips & the risk of frying them would increase.

My build uses 10 watt LEDs & I fed the leads (solid wire) through the hole in the tab on the LED & bent them around for a good mechanical connection even before soldering. I also used spring loaded heat sink clips during the soldering process to minimize the risk of too much heat getting to the chips. One of the things I like about the 10 watters compared to the larger multichips is the ability to trim the soldering tabs with a pair of cutters allowing me to slide a piece of heatshrink tubing over the connection to protect it from moisture.

Here's a photo showing 3 of my LEDs. One before solder connections, one soldered with heatshrink tubing ready to slide over the connection & one completed.

The extra pair of wires on each LED are the fan wires which I decided to hard wire to the LEDs. I will be cutting them & wiring them to a separate 12VDC power source so that they run at full speed all the time. Since my build is parallel & I'm underdriving the LEDs most of the time, the fans need a kick start in the morning when I start them at 4 volts. This is fine as long as I'm home, but not an option when I'm on vacation.

 

[tomservo]

Silicone is usually acceptable on electrical stuff, although it's generally preferred to use an alcohol curing type, you won't have any problems with the usual vinegar stuff. I think the only time you'd normally have a problem with it is if there were some that didn't cure in a reasonable time. I use SCS1200 all the time to glue on lenses and such, no problems.

Alternatives could include, Goop(TM), epoxy, hot glue, liquid nails, conformal coating(Ducky Seal)...

 

[Mike31154]

mr wilson: +1 on the wiring issues! Especially since by the time you get to a 4 pair or 6 pair cable, it's going to be THICK. Now try to find a 6 pair cable that's flexible, and you're going to be talking $4/ft or something. The 9 conductor / 18ga wire I used on a friend's build was $1/ft but just over 1/2" diameter.

You think you have wiring issues with a few large multichips. My build has 27 ten watt LEDs using 4 colours of LED each on a separate manual dimmer. I used small gauge single strand wire with terminal boards on the fixture. The fixture is fed by larger guage stranded wire from the power supplies & dimmers which are housed in the stand under the display.

This photo is still early in the process & is a great illustration of the number of wires needed for a parallel build. I've cleaned it up somewhat since then using clamps & feeding the wires through the aluminum frame with rubber grommets. Still a lot of copper.

 

[tomservo]

Mike: Nice build! If you want wiring troubles, I built a friend a fixture with 198 3w emitters.. 4 channels, I got a pic here somewhere.. This is the one I used the 18/9 cable for. Each channel's LEDs were run in parallel with the other strips, which makes for some odd voltage drivers and fairly high currents on the blues, hence the 18 gauge wire. Thankfully it turned out we didn't need a fan so there is 1 wire unused. Now, how's that for off topic??? ;P

On the fans, get yourself a PWM controller from a popular online auction site, I just recently ordered 2 capable of up to 3A, pretty small and they run on 5-40V. With these you should be able to dial the fans down pretty far and still get reliable starts.

 

[mr.wilson]

The arrows do in fact point to the + & - terminals.

 

[mr.wilson]

How are the commercial fixtures attaching the multi-chips to the electronics?

They use the terminals on the block, not the tabs.

 

[joeogio]

<iframe width="640" height="360" src="http://www.youtube.com/embed/FOkRi54uzmg" frameborder="0" allowfullscreen></iframe>
First version of my lights are up and running. In the end i chose to only use one 200W driver and two 50W drivers. So it's 2x100W RB / 10K white and 2x50W 10K white at the moment. Sorry for making such a crappy video, but I couldn't be bothered to bring out my real camera after building this stuff, doing the Noob video guide, watching the Eurovision Song Constest, going to the recycling station, the store, a gardening store + planting 8 kinds of chili this weekend..

what leds are you using on this tank?

 

[Lassef]

what leds are you using on this tank?

Look at his post 1, 4 and 77

Sincerely Lasse

 

[Mike31154]

The arrows do in fact point to the + & - terminals.

Indeed. Upon looking more closely at the photo I can make out the +- markings in the plastic next to the tabs. I'd still use the 'wings' though. Much easier to solder particularly for the novice. I think you could also chop up the outer tabs & actually separately feed each line of chips that way. Would be quite the wiring rat's nest though.