So I've been sketching out some different lighting models with various top shelf emitters that are available these days - for those of you following along this is because a few pages back we established that Vero can't be run in parrallel with simple AC drivers, and the high forward voltage makes running Vero in series a real pain.
I started looking at Cree XP-g2/XM-L2 alternatives. Cutter has some $15 PCBs pre-loaded 3 XP-G2 warm white in series on them - they look great. I started sketching out some ideas of running 4-6 of these in series, trying to get around 50-100W of warm white output with dimmable drives.
After more than a few hours looking at data sheets I eventually came to the awful conclusion -
this is stupid. Sure, I could build a nice array of relatively efficient LED modules, but why the hell am I trying to stitch together 12 to 18 small emitters? It just seems dumb to try to reinvent the wheel - Cree and Bridgelux have already stiched together a bunch of small emitters for us with the CXA and Vero. And they wont need me to farf around with my sub-standard soldering skillz.
Seriously: head-desk moment. But it's been useful and a nice learning experience.
So, back to the Vero. Particularly the Vero 18 - after a bunch of research I think the secret is to be a bit more conservative with my expectations and avoid running arrays of these things. The beautiful thing about the Vero is that it seems to match up really nicely with the $36 Meanwell LPF-60d-36. One driver per emitter. And it's a cheap yet reliable driver, from the budget end of the MeanWell range, offering simple resistance dimming making an easy build.
The thing is that the cheap chinese Ebay drivers arent that much cheaper. Around $20 for a non-dimming unit, with completely unknown quality, probable awful EMI and over-specced in the auction description, and will probably run much hotter. I just can't justify saving the $30-$40 for two drivers that I want to grow with for 5 years.
The LPF-60D-36 covers the operating voltage of the Vero 18 beautifully. According to the data sheet the V18 runs from 22-35V at absolute extremes, the LPF-60D-36 covers 21-36V.
The driver wont push the V-18 to max though - LPF-60D-36 gives us 1.67A (max given for the V-18 is 2.1A, nominal test current is 1.05A). At the max current the driver can feed the Vero should run at 52.8W, producing somewhere in the region of 140%-145% of nominal illumination.
MrFlux's brilliant CXA thread -
https://www.rollitup.org/led-other-lighting/743645-cree-cxa-analysis.html - has a look at the Vero, and picks the 3000k tint as the sweet spot in the range. Vero 18 3000K are only $17 on Newark for the lowCRI/high-output version. Add a couple of dollars for the wiring harness and you have an emitter that can plug straight into the Meanwell without even firing up the soldering iron, let alone the multimeter. The hardest thing looks like it'll be finding the right heatsink for my cab and attaching the Vero - (two m2.5 self-tapping screws FYI). I will need the soldering iron to hook up a 100kohm trimpot to the dimming input of the driver mind.
The only negatives to this that I can see is that the Mean Well is PWM dimming. Is this really a thing? Efficiency at very low levels wont be that great, and it can't dim to zero. Neither of these seem like a genuine negative to me - especially considering how cheap the drivers are and I don't need super-low or zero dimming.
I'm planning two 3000k V-18s for a 2.2sq foot micro cab - because I only have 90cm of vertical space I am expecting to be running these closer to 50% of max power (~55W total) than 100% of max (~105W total). With adjustable dimming output I should be able to veg and flower with these, even with only the 3000k spectrum, they look like they have enough blue in the output.
Does this plan look like it will succeed? Anything I've missed here?
If this looks right to you it means that if you're US based and source a cheap Ebay heatsink you can strap to it two Vero-18s powered by two LPF-60D-36. You'll have built a dimmable warm white panel with 105W of output for about $100 bucks US. With a 5 year guarantee for the drivers. Without having to solder any parts more critical than a couple of $2 trimpot. This is truly insane.
Driver link -
http://www.meanwell.com/search/LPF-60D/LPF-60D-spec.pdf