Lighting Finished my Mars to Cree today

[kcmoxtractor]

nice! i am about to build 280w worth of COB fixtures today! 4x meanwell hlg 60h-c700a
drivers and 3x 4000k bridgelux vero 18 chips per driver, should be 43-45% efficient, passive
cooled on a heatsink usa 4.85" profile.

 

[Atulip]

3070s are only in 36v, you could put 3 x 3590s 72v, a little less efficiency than the 6 x 3070s, but a little cheaper.

 

[kcmoxtractor]

here's a vid from my first fixture

 

[kcmoxtractor]

The newer Mars300 are 60x5w, actual watts 135w or so. 2 x 55-100v .7A drivers(some variances between different 60x5 models I had, but all similar) the older Mars300 100x3w should have 3 drivers in it, maybe 4, can't remember, but they are the same .7A drivers. Similar drivers in the Mars 2 series also.

Good for 1 x 72v cob, or 2x 36v cobs. You can also use up a little of the spare voltage with the 18v cxb15 series, I did in 2 of mine, with parallel to cut the amps down on the smaller chips.

did you test the forward voltage using a multimeter before you wired them in parallel?
it can cause thermal runaway if they don't have the same Vf. it's much easier to wire series
strings of 3 or more cobs in parallel because you can balance the Vf between each series
string.

 

[Atulip]

Not necessary, even if one chip took all available current, it's still below nominal on the 15 series. But you can simply toss fuses in a situation where the total amps would blow your chips.

They're wired series parallel with the 72v 3590 on the same Mars300(you can see it in the other DIY Mars to Cree thread below)

 

[dcat0921]

What do you think the coverage on this would be as opposed to the original setup?

 

[Ripper]

here's a vid from my first fixture

Dude that looks great

 

[Ripper]

What do you think the coverage on this would be as opposed to the original setup?

I can tell you the spread is twice if not more then the original on mine

 

[pop22]

Aluminum is soft enough that steel machine screws will self tap easily, just be sure to drill the proper size tap hole.

@Ripper Looking good. I'm not to worried about arctic silver + kapton, I've got 4 built like that and they're all nicely in place still after 2 months so far. @Krypt247 should take m3 screws for the holders iirc, home depot, eBay, steal from work, find machine screws just about anywhere. You could also just drill straight through the heatsinks and stick a nut on the other side to avoid tapping.

@LED Borg color looks right to me. Here's one with 3000k(and supplemental 6500k), plc cx300 with 3500k, and one with 4000k 2540s.

View attachment 545752 View attachment 545753 View attachment 545754

Both 3500k and 4000k appear to work just as well for veg here. Not seeing any added stretching from the ones I vegged under 3500k.

 

[pop22]

There is no meaningful difference in output between the 36 and 72 volt cobs. In fact, amateur light builders are better off sticking with the 36v just for safety reasons, the resistance barrier of your skin is 40 volts, only .100 amps at 72V has the pontential to kill you.

3070s are only in 36v, you could put 3 x 3590s 72v, a little less efficiency than the 6 x 3070s, but a little cheaper.