Led driver dilemma

NorthernHize

NorthernHize

Well-Known Member
I currently have two cxa3070's, I also have two meanwell lpc 60-1750. Could I power a pair of my cxa's per driver and still have good results. So in other words have 4 cxa's and my two drivers?
 
NorthernHize said:
I currently have two cxa3070's, I also have two meanwell lpc 60-1750. Could I power a pair of my cxa's per driver and still have good results. So in other words have 4 cxa's and my two drivers?
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You'd need to run the CXAs in parallel in order to share the available potential (voltage) delivered from the driver (34V).

But does the 3070 version run that low in voltage, despite the low amperage? You might have to try using the LPC-60-1400 instead (42V high).
 
AquariusPanta said:
You'd need to run the CXAs in parallel in order to share the available potential (voltage) delivered from the driver (34V).

But does the 3070 version run that low in voltage, despite the low amperage? You might have to try using the LPC-60-1400 instead (42V high).
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The cxa certainly runs off my driver and is quite bright I have them hooked upright now. So in parallel the voltage stays the same and the amps get divided. The amps are my question for driving two cxa's per driver.
 
NorthernHize said:
The cxa certainly runs off my driver and is quite bright I have them hooked upright now. So in parallel the voltage stays the same and the amps get divided. The amps are my question for driving two cxa's per driver.
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I imagine you could run multiple CXAs off a single driver, all ran in parallel, as long as the driver could satisfy the COBs' voltage needs.
 
AquariusPanta said:
I imagine you could run multiple CXAs off a single driver, all ran in parallel, as long as the driver could satisfy the COBs' voltage needs.
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I agree, I am just wondering if there is a formula to figure out if the available amperage will produce enough light for two cxa's in relation to growing our little girls.
 
Divide your amps by how many COBs your going to run in parallel. Going to sound like a broken record here , Cree does not recommend running CXA arrays in parallel. Might want to have a look at their design data sheets
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JavaCo said:
Divide your amps by how many COBs your going to run in parallel. Going to sound like a broken record here , Cree does not recommend running CXA arrays in parallel. Might want to have a look at their design data sheets
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Good point, thank you.
 
The lower the amperage, the higher the efficiency. If youre running 2 x 3070s @ 875ma they are going to outperform 1 x 3070 @ 1750 in every way [Spread, heat, par]

Your driver may power your chips @ 34v but youre probably shooting the drivers efficiency by doing so. Over the course of many cycles a more efficient driver pays for itself so most of the time cannibalizing parts is really just about saving more plastic crap from ending up in the landfill than it is about saving $$$.

NorthernHize said:
I agree, I am just wondering if there is a formula to figure out if the available amperage will produce enough light for two cxa's in relation to growing our little girls.
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NorthernHize said:
So just find 4 drivers with a higher voltage rating and half of my amperage?
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For a few dollars more you could have the best. You might consider the Meanwell HLG-185H-C1050B. >92% efficiency, dimmable, and it can drive from 3-5 CXA3070s at that efficiency. Check out the spec sheet...
 

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Mechmike said:
For a few dollars more you could have the best. You might consider the Meanwell HLG-185H-C1050B. >92% efficiency, dimmable, and it can drive from 3-5 CXA3070s at that efficiency. Check out the spec sheet...
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I figure that driver and my four 3070's in my 3x3x4 grow box would kick ass!
 
NorthernHize said:
I figure that driver and my four 3070's in my 3x3x4 grow box would kick ass!
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It would. Dimmable drivers are super nice because a plant's need for light varies over the growth cycle and dimming provides a way to match those needs. I have a Kill-A-Watt meter plugged into every light I built so I can see exactly how much power it uses and I also use a Apogee quantum light sensor to measure the intensity. With these 2 tools and a dimmable driver I can give the plant exactly the amount of light it needs at every stage of growth and save power too.
 
nogod_ said:
Your driver may power your chips @ 34v but youre probably shooting the drivers efficiency by doing so. Over the course of many cycles a more efficient driver pays for itself so most of the time cannibalizing parts is really just about saving more plastic crap from ending up in the landfill than it is about saving $$$.
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Would you mind explaining this a little more, I'm not sure I really understand;
If we take 2 drivers with the characteristics;
d1 = 1000mA @ 34V - 34W
d2 = 1000mA @ 37V - 37W

As far as the COB is concerned at a 1000mA its going to output the same amount of light energy irrespective of the driver voltage.
This means that we will get best efficiency from the system if we allow the COB to operate at its highest acceptable voltage?

Thanks, UKP
 
UKpeanuts said:
Would you mind explaining this a little more, I'm not sure I really understand;
If we take 2 drivers with the characteristics;
d1 = 1000mA @ 34V - 34W
d2 = 1000mA @ 37V - 37W

As far as the COB is concerned at a 1000mA its going to output the same amount of light energy irrespective of the driver voltage.
This means that we will get best efficiency from the system if we allow the COB to operate at its highest acceptable voltage?

Thanks, UKP
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With Constant Current drivers we have no control over the forward voltage. Resistance of the COB powered on is what sets the Forward voltage. So if you have a COB with a Vf of 36 volts and you put it on a driver that has a max of 34 volts it wont run. Now say you have a COB that has a Vf of 32 volts it will still run at 32 watts on either one of those drivers. amps multiplied by voltage gives you watts so 32 volts x 1 amp = 32 watts.
 
Should have added this , Forward voltage does change with the amount of current the COB is given. So a cob with a Vf of 36 @ 1000mA will have a higher Vf @ 1400mA and a lower Vf @ 600mA. Resistance changes with the amount of amps going to the COB.
 
One thing I want to say from personal experience is that the 3070 has a vf of 38v. But I currently only drive it with 32v and it runs fine
 
NorthernHize said:
One thing I want to say from personal experience is that the 3070 has a vf of 38v. But I currently only drive it with 32v and it runs fine
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Most drivers have a bit of headroom voltage wise. So, if the rated output is 32v, the driver may not register a fault and go into 'hiccup' mode until it hits a higher than rated output. Sometimes they will work when pushing more than rated voltage but there is usually a cost in terms of amperage.
 
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