What led would work best ?
- Thread starter torontoke
- Start date
epicfail
Well-Known Member
As for running multiple cobs with 1 driver, I use the Mean Well HLG-185H-C1050* to driver 4 CXA3070s in series at 1050mA which would be perfect for a cabinet that size. I run 8 in 8 square feet. That driver is dimmable, power factor corrected and has overload protection which the fasttech drivers and LPC's do not have. The A version is dimmable with an internal pot while the B version requires an external pot but it also capable of automation with a controller of sorts. The down side (if you think it is one) is that you are dealing with 143v instead of 4 drivers at 42 volts. Anything over 50 volts is considered high voltage and the appropriate cautions should be taken when working with it. That being said, every other light you have ever used in your grow was also high voltage. I used to wire my own hps ballasts so this isn't any more difficult, actually its a little less difficult as there is no capacitor or ignitor.
I have a few cobs on individual PC heatsinks with 80mm pc fans but when I got more I went with a larger heatsink that supra had recommended. You can see some pics of them below with and without the 140mm fans attached, 1 drivers powers all the fans.
http://rollitup.org/t/efs-r-diy-led-circuits-arduino-hot-peppers-and-more-thread.840144/#post-10798641
http://rollitup.org/t/efs-r-diy-led-circuits-arduino-hot-peppers-and-more-thread.840144/page-2#post-10869092
I have a few cobs on individual PC heatsinks with 80mm pc fans but when I got more I went with a larger heatsink that supra had recommended. You can see some pics of them below with and without the 140mm fans attached, 1 drivers powers all the fans.
http://rollitup.org/t/efs-r-diy-led-circuits-arduino-hot-peppers-and-more-thread.840144/#post-10798641
http://rollitup.org/t/efs-r-diy-led-circuits-arduino-hot-peppers-and-more-thread.840144/page-2#post-10869092
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Dloomis514
Well-Known Member
Here are the main steps. Get a 3070 3000k COB. Adhere it to a cpu fan and power supply, get a Mean well driver. Maybe$100 total
TheChemist77
Well-Known Member
Soirry bro, i just learned how to use a computer. this is all new to me, im old, i can build a house, an elevator, plumbing, etc but computers out of my league i dont even know what a driver is!! but thanks for the tip!!
mc130p
Well-Known Member
A driver is just a constant current power supply. It will adjust its output voltage to "drive" the current at the rated level if the circuit's resistance changes for some reason. Wall warts are typically constant voltage power supplies, so they will increase or decrease the output current as determined by the overall resistance of the circuit.
So, for an LED circuit in series, you will want a constant current power supply (driver) so that the brightness of the LED remains more or less constant, as it will be primarily determined by the current being driven through the diode(ignoring temperature effects). They have a finite resistance, so there will be a certain voltage required to generate the current that powers the LED. All the COBs in the series circuit will have the same current driven through them.
If you want to wire them in parallel, then I think a constant voltage power supply would then be appropriate, but I'm not getting into that.
For series circuits, of diodes, first look at the data sheet to decide on your current. Then, if you don't have a multimeter, use the Vf vs. I chart and the equation V= IR to estimate R.
Next, go to your favorite power supply provider, and find all the power supplies that give your desired current.
Figure out how many COBs you want to power with the circuit, and multiply R by that number, giving the total resistance of the circuit. For series circuits, resistances add. Next, multiply R_tot and I_desired to find the voltage drop of the circuit.
Next, look at the maximum operating current, I_max, of the diodes, and figure out the minimum resistance associated with your circuit in the same way you figured out R_tot. Calculate V_max by V_max = I_max/R_minimum
Pay attention to the Vf vs. T chart, or the Vf vs I (T) chart. Is your system able to properly cool your desired setup? (not my expertise, thus I go for overkill)
Now, go back to your constant current power supply list, and find one with a maximum output voltage that is 80% or less than this V_max number(I chose 80% to be safe, you can go higher but not higher than V_max). Purchase this power supply, wire, and your COBs.
If you can't find a power supply with a low enough V_max output, then take the difference of V_max_psoutput - V_max_your_circuit, and find the value of the current limiting resistor that you will have to add to your circuit (after the cobs) by using R_current_limiting = V_diff/I_desired.
Now, hook up the + output of the power supply to the + terminal on the first cob. Place a jumper wire from the - terminal of this COB to the + terminal of the next COB. Repeat jumper wires until you get to the last COB. Connect the negative terminal of the last COB to your current limiting resistor, connect the other side of the resistor to the - terminal of the power supply. Plug in.
I think this the way to do it anyway, if it's incorrect, please fix me!! This is how I would do it, lol.
Here's the 3070 datasheet:
www.cree.com/~/media/Files/Cree/LED%20Components%20and%20Modules/XLamp/Data%20and%20Binning/ds%20CXA3070.pdf
In general, diodes are used to control the direction of current flow, however in an LED, there is a much greater voltage drop across the diode because its main function is to produce light.
So, for an LED circuit in series, you will want a constant current power supply (driver) so that the brightness of the LED remains more or less constant, as it will be primarily determined by the current being driven through the diode(ignoring temperature effects). They have a finite resistance, so there will be a certain voltage required to generate the current that powers the LED. All the COBs in the series circuit will have the same current driven through them.
If you want to wire them in parallel, then I think a constant voltage power supply would then be appropriate, but I'm not getting into that.
For series circuits, of diodes, first look at the data sheet to decide on your current. Then, if you don't have a multimeter, use the Vf vs. I chart and the equation V= IR to estimate R.
Next, go to your favorite power supply provider, and find all the power supplies that give your desired current.
Figure out how many COBs you want to power with the circuit, and multiply R by that number, giving the total resistance of the circuit. For series circuits, resistances add. Next, multiply R_tot and I_desired to find the voltage drop of the circuit.
Next, look at the maximum operating current, I_max, of the diodes, and figure out the minimum resistance associated with your circuit in the same way you figured out R_tot. Calculate V_max by V_max = I_max/R_minimum
Pay attention to the Vf vs. T chart, or the Vf vs I (T) chart. Is your system able to properly cool your desired setup? (not my expertise, thus I go for overkill)
Now, go back to your constant current power supply list, and find one with a maximum output voltage that is 80% or less than this V_max number(I chose 80% to be safe, you can go higher but not higher than V_max). Purchase this power supply, wire, and your COBs.
If you can't find a power supply with a low enough V_max output, then take the difference of V_max_psoutput - V_max_your_circuit, and find the value of the current limiting resistor that you will have to add to your circuit (after the cobs) by using R_current_limiting = V_diff/I_desired.
Now, hook up the + output of the power supply to the + terminal on the first cob. Place a jumper wire from the - terminal of this COB to the + terminal of the next COB. Repeat jumper wires until you get to the last COB. Connect the negative terminal of the last COB to your current limiting resistor, connect the other side of the resistor to the - terminal of the power supply. Plug in.
I think this the way to do it anyway, if it's incorrect, please fix me!! This is how I would do it, lol.
Here's the 3070 datasheet:
www.cree.com/~/media/Files/Cree/LED%20Components%20and%20Modules/XLamp/Data%20and%20Binning/ds%20CXA3070.pdf
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