Current will ALWAYS be regulated by varying the output voltage

GrowLightResearch

GrowLightResearch

Well-Known Member
@nfhiggs has a history of ruining good threads by spewing his ignorance and ranting. Rather than allow him to continue screwing up yet another thread I am moving his ignorance to this new thread.

Last post from previous thread:

nfhiggs said:
You are one spewing idiotic bullshit, and fucking up threads.
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nfhiggs said:
Voltage produces current. Its that simple. Stop conflating terms like Vf with applied voltage across a load. I don't give a rat's ass WHAT you've designed or how many degrees you have. Design whatever the fuck you want, you STILL have it backwards. Current through a device is determined by the voltage applied across it, and its resistance. Current will ALWAYS be regulated by varying the output voltage. And output voltage is regulated by allowing the load current to vary. Very simple concepts.

37.8 volts is simply not enough voltage to produce enough current in a Citi 048-1212 COB to even hit it's max rating of 2650 mA, much less "smoke it in a millisecond". If you allow it to heat up to 100C you STILL only get it to slightly above its max current rating.
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Background:

nfhiggs said:
And to exceed that current you have apply more voltage or allow it to overheat. Just having the current capacity does not mean it will be used.
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nfhiggs said:
It's not a CC driver they are talking about. The HLG-320-36 is a CV 36 volt driver. Its output voltage does not change until load current increases into the CV region. Under all current conditions its output will not exceed 36 volts
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nfhiggs said:
LOL... whatever. There is no current flow without voltage. Current flow in a load results from the voltage potential not the other way around. You most certainly DO control current (through the load)with voltage. Where did you go to school?
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GrowLightResearch said:
Not with a CC driver! PLEASE just stop! You obviously do not have the background to argue this.

Why is it if the CC current were to be a function of the load voltage, if you change only the load from an LED with a Vf of 24v to an LED with a Vf of 34v the current remains the same? But yet the voltage changes. Why is that?
E = I x R
Voltage (E) is a function of the LED's dynamic resistance (R) based on the LED's IV characteristics and the constant current flow (I).

It is because the forward voltage is a function of constant current (CC) flowing through the LED's dynamic resistance!
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nfhiggs said:
You are simply ridiculous in your inability to grasp this very simple and BASIC concept. The CC driver controls the load's current by varying it's voltage output as needed. If the loads temp increases and resistance drops, the driver adjusts the VOLTAGE downward to maintain the current at the same level. Do you not understand the fact that current in a load is the direct result of applied voltage? This is really VERY basic stuff.
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GrowLightResearch

GrowLightResearch

Well-Known Member
nfhiggs said:
Current will ALWAYS be regulated by varying the output voltage. And output voltage is regulated by allowing the load current to vary. Very simple concepts.
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Not always.

Forward voltage of an LED is a function of current flowing through the LED.
Just as when a constant current driver is flowing through a resistor. It is the amount of current flowing through the resistor that generates the voltage.

It's not "always" I = E/R in this case it is E=I x R where R is the dynamic resistance of the LED.
 
psychedelicdaddi

psychedelicdaddi

Well-Known Member
GrowLightResearch said:
Not always.

Forward voltage of an LED is a function of current flowing through the LED.
Just as when a constant current driver is flowing through a resistor. It is the amount of current flowing through the resistor that generates the voltage.

It's not "always" I = E/R in this case it is E=I x R where R is the dynamic resistance of the LED.
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Dude, what. Are you trying to argue thevenin and Norton are different?
 
wietefras

wietefras

Well-Known Member
OK, that would make more sense yes. If anyone knows this stuff, it's nfhiggs. I doubt he will be baited into a mud slinging contest again.

Against the guy who not long ago argued that we should only look at current when comparing efficiency, because voltages don't matter. So when I pointed out that one of the tested COBs used a higher voltage and therefore drew more power than the other, I was yelled at. It's only current that counts ya know /s
 
1

1212ham

Well-Known Member
GrowLightResearch said:
@nfhiggs has a history of ruining good threads by spewing his ignorance and ranting. Rather than allow him to continue screwing up yet another thread I am moving his ignorance to this new thread.
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1. It takes two to argue.

2. Do you have actual hands on experience driving Citizen CLU048-1212C4 cobs with Meanwell HLG-xxxH-xx series constant voltage drivers?

3. I do have that experience.

4. When I get time I'll power up a citi 1212 with 36 volts from a constant voltage source and the answer will be known.

5. I'm going to watch football first.
 
GrowLightResearch

GrowLightResearch

Well-Known Member
psychedelicdaddi said:
Dude, what. Are you trying to argue thevenin and Norton are different?
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No, it's not a linear circuit, we are dealing with a dynamic resistance. Applying Ohm's Law, keeping it simple.
When @nfhiggs said

"Current through a device is determined by the voltage applied across it, and its resistance. Current will ALWAYS be regulated by varying the output voltage." ​

he was implying the LED's forward voltage (his output voltage) is acting as a voltage source rather than a function of the current source and the LED's dynamic internal resistance.
With a current source there is no voltage being applied. The output voltage cannot regulate anything, it is a result of E = I x R, not regulating the current as in I = E/R. It can only be varied by changing the current. The LED's resistance is a dynamic function of current (and temperature). The LED's forward voltage can only remain fairly constant by the LED's resistance decreasing with an increase in current and temperature.

"37.8 volts is simply not enough voltage to produce enough current in a Citi 048-1212 COB to even hit it's max rating of 2650 mA, much less "smoke it in a millisecond". "​

Yet Mean Well makes an LED 36v driver with a capacity of 16.7 Amps. @nfhiggs lacks the understanding that the voltage is the result of the current flowing through the dynamic resistance of the LED. As current is increasing the dynamic resistance of the LED is decreasing. There is very little increase in forward voltage with respect to the amount of increasing current.

The way this started is someone wanted to connect a single citi 1212 to a Mean Well HLG-600H-36B and have 1800 mA current flow.

nxsov180db said:
So if I hook up 1 Citizen 1212 to a MW 600H-36B it will only draw 1800 ma? The COB won't be immediately over powered and burn out?
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nxsov180db said:
So just so we’re clear there is no way to over power (current/amps/watts) an led/cob with the driver we are talking about?
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I said to context a 10.7KΩ resistor to the white and blue dim wires. I was then told that was not necessary the driver would know to take it to the max current because it was operating in the "safe zone".

The bottom line is you use the DIM control on the driver to regulate the current through an LED. You do not allow the driver to magically know the desired current and rely on the the max voltage of the driver vs. the LED's forward voltage to limit the current.
 
GrowLightResearch

GrowLightResearch

Well-Known Member
wietefras said:
Against the guy who not long ago argued that we should only look at current when comparing efficiency, because voltages don't matter. So when I pointed out that one of the tested COBs used a higher voltage and therefore drew more power than the other, I was yelled at. It's only current that counts ya know /s
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Your mind is like a sieve. It remembers very little and fills in what you forgot with bullshit.
 
P

PurpleBuz

Well-Known Member
GrowLightResearch said:
No, it's not a linear circuit, we are dealing with a dynamic resistance. Applying Ohm's Law, keeping it simple.
When @nfhiggs said

"Current through a device is determined by the voltage applied across it, and its resistance. Current will ALWAYS be regulated by varying the output voltage." ​

he was implying the LED's forward voltage (his output voltage) is acting as a voltage source rather than a function of the current source and the LED's dynamic internal resistance.
With a current source there is no voltage being applied. The output voltage cannot regulate anything, it is a result of E = I x R, not regulating the current as in I = E/R. It can only be varied by changing the current. The LED's resistance is a dynamic function of current (and temperature). The LED's forward voltage can only remain fairly constant by the LED's resistance decreasing with an increase in current and temperature.

"37.8 volts is simply not enough voltage to produce enough current in a Citi 048-1212 COB to even hit it's max rating of 2650 mA, much less "smoke it in a millisecond". "​

Yet Mean Well makes an LED 36v driver with a capacity of 16.7 Amps. @nfhiggs lacks the understanding that the voltage is the result of the current flowing through the dynamic resistance of the LED. As current is increasing the dynamic resistance of the LED is decreasing. There is very little increase in forward voltage with respect to the amount of increasing current.

The way this started is someone wanted to connect a single citi 1212 to a Mean Well HLG-600H-36B and have 1800 mA current flow.




I said to context a 10.7KΩ resistor to the white and blue dim wires. I was then told that was not necessary the driver would know to take it to the max current because it was operating in the "safe zone".

The bottom line is you use the DIM control on the driver to regulate the current through an LED. You do not allow the driver to magically know the desired current and rely on the the max voltage of the driver vs. the LED's forward voltage to limit the current.
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you are missing one basic point

the Meanwell HLG-600H-36B is a CV+CC driver, It will not exceed a maximum of about 37.8 Volts (voltage adjust range of the HLG-600H-36A) the current will not be high enough to burn out the COB. Per the citizen datasheet the gen 6 1212 at 37.8 Volts the current will be ~2000ma.

Look at the meanwell spec sheet for "DRIVING METHODS OF LED MODULE". Its quite clear what the voltage limit is doing. Thanks to bobby for the RED ARROW!


 
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wietefras

wietefras

Well-Known Member
GrowLightResearch said:
Your mind is like a sieve. It remembers very little and fills in what you forgot with bullshit.
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You are correct that all I remember from you is bullshit, but that's because that's all you post.

Here you go though:
The Vero 1750 Vf measured 27V the other two, 34V.
...
All are on the same scale and they were driven with the same 290mA current.
...
It appears the Luxeon Red Meat is the big winner. It had a PAR flux about the same as 12 Deep Red (658nm) and 4 Deep Blue (451nm) Luxeon Rebel LEDs on a 12" strip with a Forward Voltage of 35.5V.
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So we have things running at 290mA but also on 27V, 34V and 35.5V which makes them incomparable, but according to you I'm crazy for pointing that out that since they all get the same current and that's all that matters.

And then later you pretend to throw a twist that we should be looking at "photons per watt". While you are posting PPFD spot measurements (which were not corrected for watts), so yet another fail.

Also, extra hysterical credit for how you are "correcting" your PPFD measurements for inverse square law to adjust them to the "standard distance of 1 meter".

It just never ends
 
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GrowLightResearch

GrowLightResearch

Well-Known Member
wietefras said:
Also, extra hysterical credit for how you are "correcting" your PPFD measurements for inverse square law to adjust them to the "standard distance of 1 meter".
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This is the part you do not understand.

I measure the PPFD.
I measured the forward voltage.
I left the current the same.
I measured the distance from LED to sensor.

With that I can calculate the wattage.
I can then calculate the PPFD per watt.

I then use PPFD/watt and Inverse Square Law to make them "comparable" at any height. I chose to compare them at 1 meter.

I used a current of 700mA becasue that was what the OP asked me to do for him.

Now let';s look at what you have said in the past.
wietefras said:
Bullshit again. You don't need to measure PPFD. Just divide PPF by surface area. Geez you even don't understand that?
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This shows your ignorance on this topic. That is so not true.

You can only make a gross estimate when crossing geometries. You NEED to measure PPFD as it is nearly impossible to get anything near an accurate calculation.
Dividing PPF by area will get you nothing near PPFD.

PPF has no relationship to area. It is a measurement of non-directional total emitted power.
PPFD must be specified with a height or it is useless. This is why conversion factors without a height do not work.
You also need the spacial distribution of radiation to make the calculations. LEDs are not an isotropic light source.


Just becasue you found something like this on the Internet does not mean it is true:
https://docs.agi32.com/AGi32/Content/adding_calculation_points/PPFD_Concepts.htm

Yes you can calculate PPF from a SPD and Lumens/Watt. It can give you NOTHING about irradiance. It must be measured. You can estimate but very inaccurate to the point of being useless. The part in that link about conversion factors and converting PPF to PPFD is all disinformation being passed around. The blind leading the blind.

PPF will give you a rough comparison of two different LEDs.

A PPFD calculation requires the distance the photons travel, the angle at which the photons were emitted from the LED, and the spacial distribution of radiation. The conversion factor must be stated with a specific distance.

wietefras said:
And then later you pretend to throw a twist that we should be looking at "photons per watt".
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More specifically the number of photons that reach the target area (e.g the leaves of the plant) per watt.

_________________________________________________


Remember you say ISL does not matter? Stupid as stupid gets:


wietefras said:
No it's not. Uniformity and wall losses are what matters. Especially the wall losses are usually grossly underestimated which causes people to use completely wrong materials to cover their walls. Like white paint or diamond pattern foil.
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GrowLightResearch

GrowLightResearch

Well-Known Member
1212ham said:
One citizen CLU048-1212 powered at 37.8 volts constant voltage.
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Why would you do that? Do you not care how much current is flowing?

Is a 36v driver appropriate to use on an LED with a Vf of 37.75v?

Which Mean Well driver should be used for this LED? A 36v or 42v?
When choosing a driver for an LED what voltages do you look at in the LED and HLG datasheets?
 
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