Eb strips Coco and how much height do I need?

[cobshopgrow]

Im really not sure. But it would probably take some efficiency away from the dimming

the nice thing with pwm dimming is that i shouldnt cost you much efficiency, if any., on is on and off is off .
Designed a led driver 10y back and diged a bit deeper then.

I also think geenegrene had a very good english explanation of this.

 

[1212ham]

I believe the control electronics adjusts the duty cycle to target a voltage or current set point. A filter smoothes the output so it's steady dc, not on/off.

 

[wietefras]

Indeed Mean Well ELG drives don't do PWM on the output. They adjust the either voltage or the current, or both.

PWM can be used on the input. The three ways of adjusting the dim setting (ie resistor, applied voltage or the duty cycle) are all changed into a voltage by the dimming circuit. This voltage is then used to adjust the driver output.

 

[cobshopgrow]

Indeed Mean Well ELG drives don't do PWM on the output. They adjust the either voltage or the current, or both.

PWM can be used on the input. The three ways of adjusting the dim setting (ie resistor, applied voltage or the duty cycle) are all changed into a voltage by the dimming circuit. This voltage is then used to adjust the driver output.

Great that there is one with a deeper knowledge about the meanwell internals.
You may have a clue how they can achieve a dimming below 10% by current dimming without using a extra duty cycle?
i simply want to know.
only thing i know is this

 

[wietefras]

You may have a clue how they can achieve a dimming below 10% by current dimming without using a extra duty cycle?

Mean Well actually states that from dimming level 8% and lower the output can be anything between 0% and 8%. So they simply don't do anything to improve output for that use case.

Efficiency would be horrible at that level anyway, so why would you even care?

 

[Horselover fat]

You can use PWM on the 3in1 dimmable drivers if you want to use a computer to dim your lights. A Raspberry or an Arduino can be used to send the PWM signal.

I'm planning on going that route myself, when I have the time to study how to do it. I'm thinking of doing sunrises and sunsets. I'm not sure if sunset and sunrise have any other effect on the plants, but I want to have the leds come on in one end of the tent first so the other half starts turning that way. Then in the evening the other way round. I think it might do good for them to move a bit on their own.

 

[1212ham]

Indeed Mean Well ELG drives don't do PWM on the output. They adjust the either voltage or the current, or both.

Are you saying PWM is not used to control output voltage and current, or just agreeing that the output is filtered to smooth out the pulses?

 

[cobshopgrow]

thanks, got it they simply cant do below 10%
they may should write it abit clearer instead of stating 0-100% dimming, as this is normally related to a real duty cycle dimming.
That expalins it, they cant, am a bit dissapointed by meanwell, while seeing we are not their main market.

I am not interessted to dim below 10%, i am interessted to use a more efficient bigger driver and dim it down efficient, by pwm.

 

[weed-whacker]

If u run an hlg on 120v u get about the same efficiency as elg on 240v fyi

And the elg sims down to 0%

Also pwm is the least efficient dimming solution
Better lumens per watt at lower current

 

[cobshopgrow]

Also pwm is the least efficient dimming solution
Better lumens per watt at lower current

better lumens per watt at lower current is correct, but you get something wrong there.
the average current of a PWM is the current.
the led die cools down in the off phase.
i can go deeper, but PWM is the most efficient way to dim a led.

 

[weed-whacker]

better lumens per watt at lower current is correct, but you get something wrong there.
the average current of a PWM is the current.
the led die cools down in the off phase.
i can go deeper, but PWM is the most efficient way to dim a led.

Ok
Didn’t know that

 

[wietefras]

I am not interessted to dim below 10%, i am interessted to use a more efficient bigger driver and dim it down efficient, by pwm.

Mean well drivers already get around 95% efficiency. How much more do you think you are going to get?

PWM is not more efficient than a proper switching power supply with dimming contol like Mean Well produces.

The leds run less efficient at the maximum current too. Run a led at 2000mA at 25% PWM, it still runs at 2000mA and has much lower efficacy than if you run it at 500mA. It will easily be 20% to 30% less.

better lumens per watt at lower current is correct, but you get something wrong there.
the average current of a PWM is the current

You sure got that wrong yes. Temperature is much less relevant to efficay than current is.

Efficacy tests done on leds are usually pulsed measurements. The pulse is short enough to prevent the led heating up. Just like you would get with PWM. So you will get the same crappy efficay when you blast the leds at the full power as is demonstrated during those pulsed measurements.

That's why we use these highly efficient Mean Well drivers instead of cheap crappy PWM drivers.

Didn’t know that

That's because it's not true

 

[wietefras]

Are you saying PWM is not used to control output voltage and current, or just agreeing that the output is filtered to smooth out the pulses?

I'm saying that PWM is only used as one of the input options for a 3 in 1 dimming controller.

The ouput is not PWM at all. It's a smooth DC output of the selected current/voltage .

 

[weed-whacker]

I'm saying that PWM is only used as one of the input options for a 3 in 1 dimming controller.

The ouput is not PWM at all. It's a smooth DC output of the selected current/voltage .

Hahaha

I couldn’t be bothered arguing with the bone head
Especially in a thread that’s been derailed by a pissing contest about led knowledge where most of them are spouting myths

Oh btw this thread is about hight requirements for flower chambers everyone

 

[cobshopgrow]

@wietefras exactly, i wanna get the 95% over the whole range, yes.
Lets assume we have a led like the bridgelux driven allready very low, below 700mA max.
The efficiency of the led wont gain much more below this point (for the bridgelux!).
Only thing we can improve is keep up the drivers efficiency while dimming and there PWM could be sexy.
You assume that i wanna drive em peak current at 100%, thats not correct.
Otherwise thanks for the info, i learned some.

@weed-whacker
Anyway initially i just recommended something which can dim lower then 50% if youre aiming for a low hanging height.
If youre going for the usual 30w plus per suqare feet you will need it.
F.e. i use 30cm, a good foot, hanging height and without beeing able to go 25% it wont work for me.

 

[1212ham]

Hahaha

I couldn’t be bothered arguing with the bone head
Especially in a thread that’s been derailed by a pissing contest about led knowledge where most of them are spouting myths

Oh btw this thread is about hight requirements for flower chambers everyone

Pissing contest? You're the one getting hostile and insulting. As far as the thread getting derailed, your question was answerd on the first page and has been answerd many times before. EB's can almost touch the canopy.

 

[1212ham]

better lumens per watt at lower current is correct, but you get something wrong there.
the average current of a PWM is the current.
the led die cools down in the off phase.
i can go deeper, but PWM is the most efficient way to dim a led.

The leds run less efficient at the maximum current too. Run a led at 2000mA at 25% PWM, it still runs at 2000mA and has much lower efficacy than if you run it at 500mA. It will easily be 20% to 30% less.

I think I can explain... somebody correct me if this is all wrong.
PMW is the efficient method to control power, but not the most efficiant way to drive LED. There's a good solution though, Meanwell drivers use 65KHz pmw internaly to controll the power, then filter that power and deliver smooth DC at the ouput. I've had a scope on the output and it's as smooth as a baby's butt.

 

[cobshopgrow]

my above quoted doc is refering to leds,but looks to be outdated there is a lot to read about it, when i dealt with it i was after real 100% dimming and no color shift.

yes, i think your explanation hits it.
Any switching supply will work with duty cycles internally otherwise it wont be a siwtching one, or,? to become some dc voltage it goes in a capacitor.

the info with scope proves it 100%, while i am allready convinced that the meanwells just put out some dc.
thanks a lot.

still would love to see a driver set to the optimal drive point and dimmed with pwm from there.

 

[weed-whacker]

Pissing contest? You're the one getting hostile and insulting. As far as the thread getting derailed, your question was answerd on the first page and has been answerd many times before. EB's can almost touch the canopy.

Lol
My question wasn’t about distance from led to canopy actually

It was about total hight needed in flower chamber

And I assure u if I was getting aggressive u would know about it

 

[Horselover fat]

@wietefras exactly, i wanna get the 95% over the whole range, yes.
Lets assume we have a led like the bridgelux driven allready very low, below 700mA max.
The efficiency of the led wont gain much more below this point (for the bridgelux!).
Only thing we can improve is keep up the drivers efficiency while dimming and there PWM could be sexy.
You assume that i wanna drive em peak current at 100%, thats not correct.
Otherwise thanks for the info, i learned some.

@weed-whacker
Anyway initially i just recommended something which can dim lower then 50% if youre aiming for a low hanging height.
If youre going for the usual 30w plus per suqare feet you will need it.
F.e. i use 30cm, a good foot, hanging height and without beeing able to go 25% it wont work for me.

Use a smaller driver. "Problem" solved.