Questions about dimming

tstick

tstick

Well-Known Member
Are there any dimmers that are "ratcheted" or "indexed" to correspond to a specific level of dimming?

For example: If the dimmer can go down to 10% of full power at the low end and 100% of power at the high end, then there must be corresponding levels in between those extremes....but there is no precise way of knowing exactly what those levels are unless there is something to physically/visually indicate it.

I think someone once posted a "Kill-A-Watt" thing (?) that could be adjusted and had a digital display of exactly how much power was being pulled from the wall -thus corresponding to a certain level of dimming to the light...I could be wrong...but I think that's what it was...or something like that. Does that make sense? :)

I have noticed that, when using a common type of dimmer, there isn't always a smooth change in the light output as the knob is turned up or down....sometimes it "jumps" up or down in a somewhat random way. I think this is a type of dimmer found on many light fixtures - a potentiometer type? I'm not sure of the term. And the other thing about those dimmers is that I heard some of them go out and need to be replaced.

Please inform me about dimmers!
Thanks
 
Rahz

Rahz

Well-Known Member
Yes, dimmers aren't exact but you could use a kill-a-watt to find a specific ballpark current and mark it. Another option is to use a rotary dial or even a 3 way switch (on on off) or 2 way switch (on off) and incorporate resistors that would dim the lamp to a specific current.
 
tstick

tstick

Well-Known Member
Rahz said:
Another option is to use a rotary dial or even a 3 way switch (on on off) or 2 way switch (on off) and incorporate resistors that would dim the lamp to a specific current.
Click to expand...
Are there any pre-fab dimmers like this available?
 
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VegasWinner

Well-Known Member
tstick said:
Are there any dimmers that are "ratcheted" or "indexed" to correspond to a specific level of dimming?

For example: If the dimmer can go down to 10% of full power at the low end and 100% of power at the high end, then there must be corresponding levels in between those extremes....but there is no precise way of knowing exactly what those levels are unless there is something to physically/visually indicate it.

I think someone once posted a "Kill-A-Watt" thing (?) that could be adjusted and had a digital display of exactly how much power was being pulled from the wall -thus corresponding to a certain level of dimming to the light...I could be wrong...but I think that's what it was...or something like that. Does that make sense? :)

I have noticed that, when using a common type of dimmer, there isn't always a smooth change in the light output as the knob is turned up or down....sometimes it "jumps" up or down in a somewhat random way. I think this is a type of dimmer found on many light fixtures - a potentiometer type? I'm not sure of the term. And the other thing about those dimmers is that I heard some of them go out and need to be replaced.

Please inform me about dimmers!
Thanks
Click to expand...
Eradicate behavior means your potentiometer is not that good. Get a better one regarding settings get a PVM 510 power meter and connect it into your add system like this one.20170317_115359.jpg
 
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Photon Flinger

Well-Known Member
How about using pulsed (eg. PWM) current rather than stabilized DC to the cobs? Not the pot dimmer, but using pulsing to get better efficiency to the cobs. Bridgelux data sheets always reference pulsed efficacy and recommend using it for dimming.

Any vendors weigh in on this? Pros and cons? Meanwell has some PWM units that go between the driver and light source to provide PWM dimming function. PWM is supposed to be better as it reduces waste energy, at least with electric motors. But plants are a whole different ball game.

I have been using PWM drivers to run some Vero 29 C this cycle and they work just fine. The max amp is 700ma from the driver and the duty cycles run between 1 and 99% at a rate of 3khz. PPFD measurements are really good and don't seem to be that much different than stabilized DC but the heat difference is quite noticeable. For the heat reduction it could be worth it as I am just using simple aluminum sheet without any other heat sinks. With the gen 7 Veros, Bridgelux datasheets show they can be driven to twice nominal for short duration, eg. pulsed.

Maybe it is a new option to consider.
 
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Photon Flinger

Well-Known Member
VegasWinner said:
For dimming the pot is just as efficient as pwm
Click to expand...

No, I am not referring to the dimming function on the meanwell cc drivers but rather the DC to the cobs. The common meanwells are providing a constant current that is stabilized at that DC value for the driver, eg 1400ma. PWM uses pulses of constant current that are turned on and off really fast to drive the cob.

It works well for visual dimming so long as the flicker rate is above 60hz which is where it starts to be perceivable to the human eye. Can be annoying to take pictures with a digital camera but it looks the same as stabilized DC.

Likewise, I don't think it affects the plants negatively but I wanted to see if anyone else is using PWM drivers and having good results. It might be similar to the performance difference between magnetic and digital ballasts of future past since the concept is similar.
 
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VegasWinner

Well-Known Member
Photon Flinger said:
No, I am not referring to the dimming function on the meanwell cc drivers but rather the DC to the cobs. The common meanwells are providing a constant current that is stabilized at that DC value for the driver, eg 1400ma. PWM uses pulses of constant current that are turned on and off really fast to drive the cob.

It works well for visual dimming so long as the flicker rate is above 60hz which is where it starts to be perceivable to the human eye. Can be annoying to take pictures with a digital camera but it looks the same as stabilized DC.

Likewise, I don't think it affects the plants negatively but I wanted to see if anyone else is using PWM drivers and having good results. It might be similar to the performance difference between magnetic and digital ballasts of future past since the concept is similar.
Click to expand...
Sure I use those, as well. I have used them on cxb's, full spectrum cob's and mono's, as well. I created the GrowGreen Controller for pwm dimming and on/off control I can dim both meanwell hlg style drivers and DC LDDH drivers up to 1500mA. No flicker with LDD style drivers work fine.The hard part is finding 1500mA LDD drivers as I posted how that works and now there are none available. rapidleds has a 4up driver board for the DC LDD drivers but no drivers. I run lots of different cob's on dimmers with a controller, psu, and driver board.
 
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1212ham

Well-Known Member
That is a 240 volt AC dimmer. I have serious doubts about using a dimmer on the ac input to a LED driver.
 
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VegasWinner

Well-Known Member
xX_BHMC_Xx said:
Dude wtf are you talking about? Did you even look at the pic?
Click to expand...
Yes i did wtf back at you. Dont see 240 on my mobile device I see a wall dimmer 110 or 220 if you using 220 it works they also make a 110 also. Like to fight i see defines you so well go smoke and chill your ass is showing wtff
 
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Photon Flinger

Well-Known Member
VegasWinner said:
Sure I use those, as well. I have used them on cxb's, full spectrum cob's and mono's, as well. I created the GrowGreen Controller for pwm dimming and on/off control I can dim both meanwell hlg style drivers and DC LDDH drivers up to 1500mA. No flicker with LDD style drivers work fine.The hard part is finding 1500mA LDD drivers as I posted how that works and now there are none available. rapidleds has a 4up driver board for the DC LDD drivers but no drivers. I run lots of different cob's on dimmers with a controller, psu, and driver board.
Click to expand...

That great to hear - did you notice a difference between the two? I am not saying one is better over the other, they just are two different functions. If plants are ok or even perform better with PWM at certain frequencies that could introduce a whole new variable to consider.

I noticed meanwell also has a pwm dimmer unit inline between the cc driver and light source that sounds like a basic version of your controller. If PWM is found to be beneficial then folks can easily upgrade.

From the results so far on this cycle I can say for certain that it isn't detrimental. Temps are lower, PPFD numbers are great and plants are very receptive to the light.
 
Nugachino

Nugachino

Well-Known Member
Will that dimmer not work with the driver? The power going into the cobs is ac. I should be able to use that for the mains on/off.
 
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