diy version of low profile led propagation fixture for small area?
- Thread starter bri77
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- diy led bar propagation
iHearAll
Well-Known Member
i was playing with this cute 12uF ac cap in series with the wall and pulled ou 15v after rectifying. i forgot that i could just make a huge resistance with one of these. for the weight and size its an easy power voltage divider.
mauricem00
Well-Known Member
someone else that likes playing with high voltage generators.50 years ago I use to play with TV flyback transformers
mauricem00
Well-Known Member
I used a 15uf 400vac series capacitor to drive a string of 20 bridgelux 3 watt full spectrum diodes at 300ma.with a 470uf 200v electrolytic for an output capacitor and it worked very well driving the leds to about 19 watts. motor run capacitors are cheap on ebay
iHearAll
Well-Known Member
iv built 3 of these circuits for my room using 100w cheepo cobs. a 210w using 400w of chips. a 220w using 400w of chips. and a 300w using 600w of chips. they should last quite some time even though theyre cheepo LEDs. efficiency of the LED per lumen or whatever is a whole different story. theyre actually only two panels but the bigger one is made of monochromatic leds so i wanted to be able to do the only blu or only red during different plant cycles. so i had to build them onto separate circuits
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iHearAll
Well-Known Member
thats exactly what im doing hahahahha. couple of MKP caps and irf540s two 12v zeners and 2 UF4007s and 180ohm resistors on the gates. self res flyback driver using LC.
iHearAll
Well-Known Member
hot sex i want to try this for my veg box.
Airwalker16
Well-Known Member
What the hell is happening here?
Airwalker16
Well-Known Member
And are you saying that you're powering cobs with these $3 parts instead of using meanwell drivers and the like? Is it safe?
iHearAll
Well-Known Member
yep, im pumping 10,000v into my beer cuz im bored
iHearAll
Well-Known Member
@Airwalker16 fuse your circuit for your current rating and youll be a happy campyer
iHearAll
Well-Known Member
but ballast it for a safe value for the LEDs of course. so if your max is 1 amp then build it for .6 or .7 of course and set the fuse right at the max for the LEDs in case you're like me and play with electricity all day and surge your house or lightning strikes a powerline outside. or if your fans die for some dumb reason and the LEDs overheat. since the forward current and heat are proportional, if the heat increases the door for the current will open up and theyll gradually pass more current
iHearAll
Well-Known Member
yea you just need some weed to smother it with
iHearAll
Well-Known Member
btw you can totally test the circuit with no LEDs attached to the rectifier. just wire up the capacitor to the wall plug, rectify the output and measure the voltage with a multimeter.
then check your math on what the voltage range on the LEDs is for the number in series you're using. if it add up to less then what your getting on the dc part of the rectifier then dont even bother hooking up the LEDs and get a smaller capacitor
if the max voltage of your LEDs is higher than what you're seeing on your meter from the rectifier then you can plug up your LEDs to it and theyll just draw whatever current it takes to get them to that particular voltage and you dont have to worry about the current much.
then check your math on what the voltage range on the LEDs is for the number in series you're using. if it add up to less then what your getting on the dc part of the rectifier then dont even bother hooking up the LEDs and get a smaller capacitor
if the max voltage of your LEDs is higher than what you're seeing on your meter from the rectifier then you can plug up your LEDs to it and theyll just draw whatever current it takes to get them to that particular voltage and you dont have to worry about the current much.
Randomblame
Well-Known Member
Hey bri77,
A MeanWell HLG-60H-C700B is optimal for your needs. 100V, 700mA, max. output 70w, 91% eff., dimmable, IP67, only 35-40$ instead of 65$!
http://www.mouser.de/Search/m_ProductDetail.aspx?Mean-Well/HLG-60H-C700B/&qs=/ha2pyFaduhTgKandwNLmgKXcyRlEEnnmdDi3EindIxZbb0Jr0CQCeqoT3c
If you choose 30XP-G3, 4.000°k, S4 bin and drive them with this HLG-C driver you should get Ø10530lm total or 175,5lm/w @55°C,
~54% eff.(+3% eff. is you get S5 bin)
59,5w LEDs/(x0,91%=)65,3w total from the wall,
27,4w heat, heatsink for passiv cooling should have at least 3300cm²
(a 3mm thick Alu-Sheet 75x 25cm in more than enough(3850cm²) and ultra-flat)
32,1PAR/w,
x 4,52μMol/j(4.000°k)= 145μMol/s PPF
or
PPFD without wall losses: Ø 520μMol/s/0,28m² (3 sft).
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bri77
Well-Known Member
So I am going about this in the right way.Decide what leds you want, then choose a current that will give you the output/effeincy you need. Based on that get the minimum amount on driver to get the job done. Then I need to think about heat, right? Is there a reasonable way to estimate how much heat I'll produce and what I'll need to handle it?
IHearAll, thanks for your efforts man, but all that stuff is beyond me, you're getting into electrical engineering there, I want electrical lego.
Randomblame
Well-Known Member
Yepp, that way you can go.
You have 59,5w total x 0,54% eff. = 32,1PAR/w, the rest is heat, in this case 27,4w.
The most info's are already in my last post. Based on the XP-G3 datasheet you can expect ~27,4w heat and 32,1PAR/w of light.
To remove the heat passive you need a heatsink with at least 3300cm².
(Ø 110-120cm² surface per watt for passive cooling, Ø 40cm² with active cooling)
Simple take a 3mm thick Alu-Sheet with 75-80cm length and 25cm wide=3850-4000cm², it's the flatest way to cool the stipes properly and also cheap.. There is no need for colling fins if you have enough surface.
You can hang such a sheet 3-5cm below the ceilling. You can also turn the lateral 10cm left and right from the stripes a bit down to use the sides from the sheet as a reflector.
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