Does a dimmer change the efficiency of a COB?
- Thread starter tstick
- Start date
littlejacob
Well-Known Member
Bonjour
Another question is...does anyone know the electric save between a 90% efficient driver and a 94% one!
Or if it's easier between 84% and 94%...how many w are saved
What represent this % in $ on a year!
Have a great day ★
Another question is...does anyone know the electric save between a 90% efficient driver and a 94% one!
Or if it's easier between 84% and 94%...how many w are saved
What represent this % in $ on a year!
Have a great day ★
SPLFreak808
Well-Known Member
You have power supply efficiency and you have LED efficiency.
Driver efficiency = how much input is required for a specific output, this ratio of input to output will change as you use the dimmer function unless you have some type of high end fully regulated driver. The efficiency up swing of an LED driven at a lower wattage outweighs the drivers efficiency down swing when dimmed, dimming the cobs will make up for MUCH MUCH more then the driver efficiency loss.
When you compare efficiency, it has to be compared at the same volt X amp output of each driver tested. If one was tested 90% at 1a 70v and the other tested at 90% .5a 90v then i can assure you both drivers will have different efficiency ratings when driven at the same output. More drivers and cobs > more power
Driver efficiency = how much input is required for a specific output, this ratio of input to output will change as you use the dimmer function unless you have some type of high end fully regulated driver. The efficiency up swing of an LED driven at a lower wattage outweighs the drivers efficiency down swing when dimmed, dimming the cobs will make up for MUCH MUCH more then the driver efficiency loss.
When you compare efficiency, it has to be compared at the same volt X amp output of each driver tested. If one was tested 90% at 1a 70v and the other tested at 90% .5a 90v then i can assure you both drivers will have different efficiency ratings when driven at the same output. More drivers and cobs > more power
tstick
Well-Known Member
Awesome! Thanks!
Another question…
Let's say you have an COB fixture that isn't dimmable and you want to make it dimmable without having to rewire anything….Could you just plug the fixture into a Variac switch and dim the fixture that way? I realize that if the fixture included fans, the fans would also be slowed down, too.
Thanks!
Another question…
Let's say you have an COB fixture that isn't dimmable and you want to make it dimmable without having to rewire anything….Could you just plug the fixture into a Variac switch and dim the fixture that way? I realize that if the fixture included fans, the fans would also be slowed down, too.
Thanks!
churchhaze
Well-Known Member
Total efficiency = led efficiency * driver efficiency.
churchhaze
Well-Known Member
Try to pick the driver that is "closest without going over" so that the driver runs close to the top of its efficiency curve. You also pay a lot to buy the driver, so you should get your money's worth.
SPLFreak808
Well-Known Member
Depends on the driver. If you have something like an HLG type b & c i believe it already has a circuit that you could pop a potentiometer into it making it dimmable, because you are telling the power supply what speed to run at, you will not have too much of an efficiency loss from the driver. If your driver is not dimmable (lowers wattage through power supply) then you are shit out of luck unless you start hacking away pots at the board, not recommend lol. Sure, you could add in some type of resistance on the output line but you are just dropping driver efficiency wayyy down unless the extra resistance added were more diodes.
coolbreez1
Well-Known Member
Most of the driver spec sheets will provide a graph showing how efficient they are at different outputs, most of the dimming ones are crushed from an efficiency perspective when they are not being run at full power. Without running the numbers, it seemed that dimming did not make sense from an efficiency stand point, however dimming for short period of times while you are working on the plants to cut down on eye strain could be useful.
alesh
Well-Known Member
Generally no. There are some drivers that can be dimmed through household triac dimmers but I don't think they're used in any grow light.
The gains from a COB running soft are almost always higher than losses from a driver not running at full load.
tstick
Well-Known Member
Cool! Thanks!
I have read that some people believe that it doesn't make any sense to not have the capability to dim the fixture -since it is (apparently) fairly easy and inexpensive to do. Like, you might never use it, but IF you ever did want to use it, then it's there.
SupraSPL
Well-Known Member
You can do an awesome job growing without dimmers, but once you have them they are surprsingly useful. Also, the highest efficiency drivers offer dimming so you could think of it as a bonus. If you design your system with a good driver/COB match, the 94% efficient dimmmable Mean Well drivers end up costing about the same or even less than generic drivers/W.
As long as your COB string is loaded up reasonably close to the max voltage of the driver, there is only a very slight loss of driver efficiency when it is dimmed, even if it is dimmed very low.
As long as your COB string is loaded up reasonably close to the max voltage of the driver, there is only a very slight loss of driver efficiency when it is dimmed, even if it is dimmed very low.
SupraSPL
Well-Known Member
If you have 600W of LED dissipation and you power it with 94% efficient drivers, it would pull 638W and 38W would be dissipated as heat in the drivers and emitted into the grow space.
If you powered it with 85% efficient drivers, the system would pull 706W, about 106W would be dissipated as heat in the drivers and emitted into the grow space
littlejacob
Well-Known Member
Bonjour
Thanks supra...but I really like to know if there is a way to calculate what represent 10% efficiency on a driver?
How much $ you save on a grow?is this 10% mean you use 10% less electricity with a 94% than with a 84%?
CU
Thanks supra...but I really like to know if there is a way to calculate what represent 10% efficiency on a driver?
How much $ you save on a grow?is this 10% mean you use 10% less electricity with a 94% than with a 84%?
CU
SupraSPL
Well-Known Member
Yes you would pull 638W rather than 706W which is about 10% less electricity. But when you look at the entire non productive heat load it represents an even larger bonus:
Assuming 600W of 50% efficient COBs:
With 94% efficient drivers, 338W of heat
With 85% efficient drivers, 406W of heat
So the 94% efficient driver reduces non productive heat by 17%. So in addition to saving 10% on the lamp electrical cost it could reduce cooling costs as well.
Assuming 600W of 50% efficient COBs:
With 94% efficient drivers, 338W of heat
With 85% efficient drivers, 406W of heat
So the 94% efficient driver reduces non productive heat by 17%. So in addition to saving 10% on the lamp electrical cost it could reduce cooling costs as well.
littlejacob
Well-Known Member
Bonjour
@SupraSPL why everything you said sound clear and easy to understand!??
Are you a teacher?...lol!
It was exactly what I wanted to know!
And the heat...I never thought about it! (Maybe because I have a 50mm fan on my driver...cooool it will stay!)
First time I have 24/26ºc without extraction...perfect!(240w all include)
On the hps side I have 28/30ºc with intra/extra, fans at max(710w...)
I guess I will be close to 300gr for 240w and to 450 for 710w...1/3 more for 3 times more electricity...who want to buy hps anymore?...not me for sure!
Once you test cob it is for ever!
CU
@SupraSPL why everything you said sound clear and easy to understand!??
Are you a teacher?...lol!
It was exactly what I wanted to know!
And the heat...I never thought about it! (Maybe because I have a 50mm fan on my driver...cooool it will stay!)
First time I have 24/26ºc without extraction...perfect!(240w all include)
On the hps side I have 28/30ºc with intra/extra, fans at max(710w...)
I guess I will be close to 300gr for 240w and to 450 for 710w...1/3 more for 3 times more electricity...who want to buy hps anymore?...not me for sure!
Once you test cob it is for ever!
CU
littlejacob
Well-Known Member
Bonjour
So better buy a good one...
5% to10% electricity saving...
10cts for 1Kw (1000w)
For a 200w pane it is 2cts per hour
12h × 300days = 3600h × 2cts = 7200cts=72 $...7.20 $
3.60$ save every 100 w every years!
It is not a big concern for small panels but when you run 1000w of cob it worth it!
CU
So better buy a good one...
5% to10% electricity saving...
10cts for 1Kw (1000w)
For a 200w pane it is 2cts per hour
12h × 300days = 3600h × 2cts = 7200cts=72 $...7.20 $
3.60$ save every 100 w every years!
It is not a big concern for small panels but when you run 1000w of cob it worth it!
CU