DiY LEDs - How to Power Them

SupraSPL

SupraSPL

Well-Known Member
Yes you are correct, the 100K would work in both situations, but you would lose some fine tuning if you use a 100K to control 3 drivers. A 50K would work better.

I agree the extra cost of the 10 turns pot is quite a lot. There is no problem using the cheap one if you do not care about very fine adjustaments. The only time I need fine tuning is when I am testing drivers and LEDs. I like the sliding pots, very cool idea!

No problem running 600W in a 4X4, I think it will give you awesome results!
 
SupraSPL

SupraSPL

Well-Known Member
John L III said:
I'm really curious here. Has anyone here used the screw in light socket LED downlights?
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I have bought a few from Fasttech. They are convenient and aethestic, but built with generic LEDs and in most cases very poor thermal management. Thin heatsinks with poor thermal interface and sometimes they dont even bother to use thermal paste. Hopefully they used some beefier heatsinks for the ones you got. The drivers that are inside them are usually pretty good though. 80-88% efficient in all that I tested. I would not recommend them as grow lamps.
 
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PurpleBuz

Well-Known Member
kamikaza said:
thanks for the reply supraSPL!

i know 468w is enough to reaplace 600w HPS sucssesfuly, but i want to have more buds then from the HPS...

so i would like the builds to be able to operate between 450-600w, like the first build. if i will use the hlg-185H-C1400 i can only dim from 468w downward.

if there would only be HLG-200H-C1750....


i am thinking now of using 9 x HLP-80H-42 - http://www.meanwell.com/search/HLP-80H/default.htm

3 for each bar, 1 for each COB.

!
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sounds like a great build plan

But I am curious, since you can't fnd a perfect driver\3cob match to run close to 1.750 amps, why can't you just add one more cob and run\ them at a lower current ? Just like your first build with 4 cobs ?
 
kamikaza

kamikaza

Well-Known Member
PurpleBuz said:
sounds like a great build plan

But I am curious, since you can't fnd a perfect driver\3cob match to run close to 1.750 amps, why can't you just add one more cob and run\ them at a lower current ? Just like your first build with 4 cobs ?
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That's because i want an even light distribution.

on the four bars build, there will be four COBs spacing 30 cm apart. and the four bars will also be 30 cm apart. so i will have one COB for each squere feet, exactly.

on the second build, i will have the COBs spacing 40 cm apart, and so will be the bars.

so each 'squere' of 40 x 40 cm will have an COB in the middle.

i am trying to avoid an uneven canopy, a common problem with HPS - look at all the grow ways out there - scrog, vertical grow, sog - all devaloped to defeat that problem.

i will be growing 9 cuts under each build in 6 liter air pot, and i want to flower early.
 
Greengenes707

Greengenes707

Well-Known Member
SupraSPL said:
Perfectdeal_US got 50W drivers back in stock but unfortunately they are 40W junkers :(
1.275A and 87-88% efficient, non power factor corrected. Hopefully they will refund but it was a deal outside of eBay.

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I just pulled the trigger on 10 literally 5 mins ago. I will email them and see what's up. The pic was the normal good ones...so if not
i will be canceling(I went though ebay though)
 
SupraSPL

SupraSPL

Well-Known Member
Heck of a coincidence GG!

Ya they might be the perfect thing for those who are after 1.25A. After warming up some more, the efficiency is up to 88.5-89% so that is a plus. Happy to DKG.
 
SupraSPL

SupraSPL

Well-Known Member
You nailed it, I bet these were dirty cheap. They agreed to refund if I return the drivers but I have heard that before and got screwed out of $75 by sure-display. That was a different situation, the drivers were flat out defective (putting out only 700mA and squealing). I shipped them back to China and they said there was nothing wrong with them. But I do have slightly more trust in these guys so I will give it a shot.

They asked what was wrong with the drivers and I gave them the test numbers and pointed out that they are not power factor corrected like the ones pictured. The picture shows drivers sticker 1500mA and these say 1350mA, actual is 1250mA. Hopefully they will track down the good ones for us. I have scoured Ali and have never found any that were as good for as cheap. Certainly none that ship from the US. Here are some decent options for those in need. They put out 1475mA, have a good Vf range for CXA3070 and are 89% efficient.

http://www.ebay.com/itm/171401815098?var=470444964984&ssPageName=STRK:MESINDXX:IT&_trksid=p3984.m1436.l2649

http://www.ebay.com/itm/201040145983?ssPageName=STRK:MESINDXX:IT&_trksid=p3984.m1436.l2649
 
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SupraSPL

SupraSPL

Well-Known Member
Ya they said thank you for the info and they will talk to the supplier. Hopefully they get more of the JHX 30 watters because they were the best in that current range also. Cheap, 45Vf max, 810mA and 90.5-91% efficiency. Only downside they are non PFC.
 
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stemkey

stemkey

Member
SupraSPL said:
It is possible to use 12V DC power supplies to power LED strings but but the conversion from 120V AC to 12V DC penalizes efficiency (50-80% efficient). There are high efficiency power supplies available (85-90%) but they can be expensive and add unnecessary cost and complexity. After the 12V power supply we have to use a DC to DC power supply to step the voltage back up above 12V. From my testing this step up is not very efficient (80%) unless the string is very short <12V.

Another option is to use constant voltage DC to power the strings but that only works if all the LEDs on the string have the exact same vF otherwise they will experience drastically differing currents.

So those are the reasons I recommend constant current drivers and that has been my experience but I am always open to learning new things so if anyone knows a more efficient way please advise us :weed:
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What if you put 36v into the DC-DC power boost, would that be more efficient?
 
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