Now the AC side and DC output of the lighting driver is completed and mounted to the casing. The biggest changes so far have been switching over to a radial fan for cooling, dropping the bigger capacitor and replacing the series resistor with a coil, which increased the output voltage somewhat, but makes it independent of load. It also increases overall system efficiency.
The ripple is surprisingly small even with only one capacitor. The test load i used was a 89 ohm resistor, and the output voltage under load was 114V. This gives us a 1.3A current resulting in a 145W load.
I also applied thermal paste to the LEDs, so now they are ready for use.
TODO: Connecting and mounting the current regulators and connecting the LEDs.
If you have not been following my blog, then here is a quick update on the current status of my LED lighting project. I finished the first 150W module (running at 124W) and made some comparison shots with a 110W high-powered fluorescent light. The pictures are taken at manual setting with a DSLR so they represent the real difference in brightness quite well.
Currently i am working on fitting a 12V voltage regulator into the casing, so i could drive all the cooling fans from the same lighting driver without an external wall-mounted 12V adaptor.
I have also ordered 3x 100W LED emitters, that i will connect with the current 50W ones to get to a total of 450W of LED power :)
I have done quite a bit of work with LED array chips. I have found that ALL of the Chinese ones that I tested are pretty much crapola. I get more light out of a 60 watt Bridgelux array than my best 100W Chinese array.
BTW, the biggest system that I have built is 180,000 lumens (12 x 150W Bridgelux modules). The basic design uses 15,000 lumen 150 watt modules that can be configured into arrays as large as your budget allows. Each module has its own AVR based switchmode driver/dimmer/thermal manager/fault management/computer interface.
I wonder what these bridgelux LEDs would cost? A quick googling session did not give me any results, since the ones i saw were 100W/6500Lumen series, and those are clearly not what you are talking about at 100Lumen/w. I wish you could show me some comparison between the 60W bridgelux and 100W "best chinese" ones you are talking about, since those numbers sound weird. EPISTAR does in fact give you valid datasheets, and they indicate 85-100 Lumen/w depending on the model.
EPISTAR is quite a well-known and reputable company even as a "chinese", and all i can say is that i am more than happy about the price compared to performance. The 100W noname ones i bought for 36$ / 100W / 9000-9500 Lumen including p&p is really hard to beat in bang for buck, and they seem identical in quality&manufacturing to the EPISTAR ones... maybe they are just the lower binned epistars sold as noname? And their light output is approximately double that of the 50W EPISTAR ones i bought before them.
So excuse my skepticism, your argument just seems like an exaggeration.
Look at this picture, the three at the left are 100W nonames, 3 at right are EPISTAR 50W.
The largest Bridgelux arrays that I have been using are the BXRA-50C9000 series. $76.65 ea from Digikey or Newark (buy 100 and they go down to $72.43!). Rated at 9750 lumens @ 2.8A / 30.4V (115 lumens/watt). 12675 lumens at 3.75A. 15,000+ lumens overdriven to 5A (as per data sheet).
As far as the Chinese ones, I have about 10 different ones all from Ebay. Various manufacturers. 50-100W. The BEST ones put out about 2/3 the light of the Bridgelux arrays at the same input power level... actual measured lumens in an integrating sphere. The worst ones are less than 50%. As they say, one experiment is worth 1000 opinions.
You see, one of those bridgeluxes cost me the same as the three chinese 100W ones i bought. Actually more since i have to pay taxes and import duties, since it is so expensive. Cheaper products are exempt from this. I am not going to invest in LED lighting before it matures. And i rather had 3 chinese LEDs compared to one better bridgelux/some other really good one. And then two bridgeluxes (one cool white, one warm white)? that would already cost 25% more than what my six cost together. Three bridgeluxes? Yes, so the voltage would be enough for my led driver. That would be expensive...
When LEDs mature, i can upgrade this to a real monster, adding 3x100W of bridgelux 150 Lumen/W LEDs for 25$ a piece. While waiting for that, i might actually finish the 12VDC supply... :P
BTW. was EPISTAR one of those you included in your testing?
Next up on my to-do list concerning this project is to cover the walls with black-white construction plastic. The white side reflects 10% less than mylar, but it is also much less expensive.
None of the Chinese arrays had a manufacturer's name... even on what was passed off as data sheets.
As far as the cost of the Bridgelux arrays... you get what you pay for. Even if the other ones were free, I'd still use the Bridgelux stuff. $75 is dirt cheap for what you get. You don't want to know what the custom CNC machined heat sinks cost... (in fact, I don't know... I wasn't paying for them).
Also, the light output of the Chinese arrays dropped of quite a bit after not that many hours of usage. They were properly driven and under active, accurate thermal/power control.
As far as LED house lighting see my experiences at: https://budgetlightforum.com/t/-/7803 My house is now totally LED driven... well over 300 LED bulbs, including some custom built fixtures with smaller Bridgelux arrays.
180 000 lumens.. Are you lighting up a stadium or what? :P
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The exact application is uhh, well, uhhh, kinda sorta classified (OK, I promised the Patrons of the Beast to not divulge its intended use). We don't want the Men In Black coming around with their flashy things taking away birthdays, now do we? (hey, if they do, my flashy thing is brighter than theirs)
I can say that the design is SWEEEEET (if I do say so myself). Unicorns quiver in its glorious presence (or maybe that's just what unicorns with fried retinas do). I wee-wee down my leg every time I see it in action. So does my seeing eye dog.
It is highly fault tolerant, fail soft, power system is dual redundant, anything and everything (and then some) that can be monitored, reported, and compensated for is. Nothing can go wrong, failure is not an option, would you like fries with that.
And it is technically a flashlight. 40 pounds of 16S 2P 20Ah A123 LiFePO4 batteries can run it for around an hour at full blast. Can run for months at min output. Even on low the thing is scary.
BTW, most stadium lights use banks of 1000 watt, 100,000 lumen metal halide lamps. LEDs are just getting to that level of efficiency (but let's see you dim one, turn it on instantly, or bounce it around the ocean/countryside, or run it for 50,000+ hours)
Wow, that sounds like amazing design, especially the fault tolerance part - I guess it is used by serious people if it has so many failover’s and redundancy. By the way, got some beamshots?
Actually the stadiums and golf courses (at least for the most of them here) use 2kW to 8kW ones. Maybe the smaller ones? I know for road works they are already using 2 or 3 units of 1kW for say a digging site of maybe 10 metres and 1 lane wide. The security gate (2 lanes) here uses a 400W LPS, that's quite bright coz it's approaching 200lm/W I think.
It sounds like a lot but it's not, but yeah it's bright though.
Some fun with bike lights!
There is a XM-L bike light here as comparison. The XM-L nearly vanished. hehe
I don't have any shareable pics of the final unit. There are some pics of a previous build of a 5000 lumen prototype here: #291
The beam is extraordinarily even and clean. Absolutely no hot spot. The later modules use a regulated current driver instead of the direct drive. Each LED has its own independent driver/thermal manager. They are all networked together.
There's talk of doing 500,000 lumens... I saw some specs for a 60 inch carbon arc searchlight that says it does 300,000 lumens (seems a bit low) with 15KW.
I got my stadium light numbers from the guy that maintains the local high school and college stadiums lights (high school football can be more rabid than pro football here). They typically use 4-8 towers with 24-32 lights on each tower. I had though that they used the bigger bulbs.
A few years ago a lot of schools had problems with their light towers falling down. Turns out that they were all made by the same company and they had corrosion problems at the base. That company went out of business rather fast.
As an optician I cry a little when I see the torture that lens goes through. And I’ve lit trees on fire a lot quicker than that cardboard. To put it into perspective… Think about harnessing the power of the sun across 48 inches and focusing it down to a point approximatly .25”… it litterally says POOF and flames erupt!
