A simple start

00heaven

New Member
Like walking barefoot on new carpet...ahh!!
I have a 3500k lm561c Qb with dimmer switch and a Horticulture Lighting Group meanwell driver....
When I use the dimmer switch am right in assuming there is a proportional reduction in electricity consumption?
Like the layout by the way, very easy to navigate and totally intuative. Bravo!
 

Vaporum

Vapor Master
Staff member
Super Moderator
Firstly, welcome to the forum. There are two very common methods of dimming LEDs and both will reduce your overall power consumption in different ways:

PWM (pulse-width modulation) drivers split the on cycle of the LEDs measured in milliseconds. For example a low-light effect of 10% brightness means the LED is only on for 10% of it's on cycle and off for the other 90%. At 50% the LED is on half of its on cycle and off half the time. The pulsing happens so rapidly that the human eye won't see it, but instead recognizes the overall average of light as being dimmed. PWM drivers do not control the current or voltage, and thus they still draw the same amount of power, they simply do so for less of a duration. Example: a 200W driver that is on a 10% cycle will pull 1/10 of the kW per hour compared to a 100% cycle (or at least this is my understanding).

The other type of dimming is analog dimming. These regulate the amount of current being fed to the LEDs, which reduces or increases the intensity. When the current changes, so do the watts being consumed. Carrying on with the example from above, if we took a 200W analog driver and dimmed it to 10%, it would only pull 20W from the wall.
 

H.a.F.

Happy Wanderer
Firstly, welcome to the forum. There are two very common methods of dimming LEDs and both will reduce your overall power consumption in different ways:

PWM (pulse-width modulation) drivers split the on cycle of the LEDs measured in milliseconds. For example a low-light effect of 10% brightness means the LED is only on for 10% of it's on cycle and off for the other 90%. At 50% the LED is on half of its on cycle and off half the time. The pulsing happens so rapidly that the human eye won't see it, but instead recognizes the overall average of light as being dimmed. PWM drivers do not control the current or voltage, and thus they still draw the same amount of power, they simply do so for less of a duration. Example: a 200W driver that is on a 10% cycle will pull 1/10 of the kW per hour compared to a 100% cycle (or at least this is my understanding).

The other type of dimming is analog dimming. These regulate the amount of current being fed to the LEDs, which reduces or increases the intensity. When the current changes, so do the watts being consumed. Carrying on with the example from above, if we took a 200W analog driver and dimmed it to 10%, it would only pull 20W from the wall.
So on the Horticulture Lighting Group 135's that have 2 "dimmer" switches, is that the difference?
 

Vaporum

Vapor Master
Staff member
Super Moderator
I just did a brief Google search and found that light uses a Meanwell Horticulture Lighting Group-100H-54A driver.

This driver has a constant current and voltage mode (1770mA@54Vdc). It also appears to have a PWM function and a 1-10VDC type dimming function. 3 in 1 as it says on the spec sheet. Without seeing the driver up close I can only guess that the two "switches" you are referring to are for the different types of dimming.
 

H.a.F.

Happy Wanderer
I just did a brief Google search and found that light uses a Meanwell Horticulture Lighting Group-100H-54A driver.

This driver has a constant current and voltage mode (1770mA@54Vdc). It also appears to have a PWM function and a 1-10VDC type dimming function. 3 in 1 as it says on the spec sheet. Without seeing the driver up close I can only guess that the two "switches" you are referring to are for the different types of dimming.
There was very little paperwork in the box, instructions on the internet for hook-up, etc. What you found is what I found info-wise. It is 2 little holes with rubber caps, each with an adjustment screw under it. One says Vo, one Io
 

H.a.F.

Happy Wanderer
Voltage and Intermittence? (or something that means "blinky" and starts with "I" :))
 

Vaporum

Vapor Master
Staff member
Super Moderator
In electrical terms I stands for current. The voltage and current according to the spec sheet does have a range of 27-54V and 1.1-1.77A. With one being Vo and the other Io, that's likely what it's controlling.
 

H.a.F.

Happy Wanderer
In electrical terms I stands for current. The voltage and current according to the spec sheet does have a range of 27-54V and 1.1-1.77A. With one being Vo and the other Io, that's likely what it's controlling.
For the non-electrical person that has no real desire to become one, which would be best to dim if needed w.r.t. plant growth?

What my stoner-mind has broken your science down to is that dimmed half-way:
PWM is a 100% dose, half the time,
Analog is a 50% dose full-time.

Close?
 

Vaporum

Vapor Master
Staff member
Super Moderator
So do you know which would be best, or does it matter?
There is an argument over which is better. When drive current is reduced it can create a color shift on LEDs. This shift varies from wavelength or CRI. PWM does not reduce current which means no color shift. I don't believe many tests have been done comparing the two dimming methods on grow lights or how much the color shift affects overall results. Perhaps this is something you could test. I doubt there would be a significant difference between the two methods of dimming overall.
 

smilley

New Member
Like walking barefoot on new carpet...ahh!!
I have a 3500k lm561c Qb with dimmer switch and a Horticulture Lighting Group meanwell driver....
When I use the dimmer switch am right in assuming there is a proportional reduction in electricity consumption?
Like the layout by the way, very easy to navigate and totally intuative. Bravo!
I have a very similar fixture.

It's kinda proportional but I use a "kill-a-watt" consumption meter with mine and use that to determine my power consumption. About $20 from Amazon. You can use a marker on the dimmer to set specific power settings or just leave it plugged in and adjust your power consumption as required.
 

00heaven

New Member
I have a very similar fixture.

It's kinda proportional but I use a "kill-a-watt" consumption meter with mine and use that to determine my power consumption. About $20 from Amazon. You can use a marker on the dimmer to set specific power settings or just leave it plugged in and adjust your power consumption as required.
Hay smiley, I'm a tight wad. I'll see the £20 item on amazon then immeadiatly go to ebay and find one for £10 then put that in my basket without looking at seller reviews. The pysical journey for a great deal of cheap (chinese) ebay electrical items is ..Factory...container ship...port...sorting depot...delivery office...my house...my bin.
I'll hit amazon on friday no detours promise
 

smilley

New Member
lol, mine is actually a cheap knock off and works great. I just used kill-a-watt because it'll take you to the right place from a search engine. I believe some of the smart plug ins will monitor power consumption and operate as a timer as well. If your on a tight budget, just guess or use a camera light meter to measure intensity instead.

Careful you don't get that light too close to your canopy. It'll bleach the leafs and interfere with growth. At full power my light is rated at 480w and actually consumes 510w. I've only done one run with it and 23 inches to the canopy was about as close as it would go before leaf damage became apparent. Start higher and let the canopy grow up to the light.
 
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