Introducing CobKits.com - specializing in DIY and Citizen COBs

Discussion in 'LED and other Lighting' started by CobKits, Aug 2, 2016.

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  1.  
    CobKits

    CobKits Well-Known Member Rollitup Advertiser

    not meanwells
     
  2.  
    CobKits

    CobKits Well-Known Member Rollitup Advertiser

    changed my travel plans, ill be around today for orders. leaving tomorrow (thurs). so thurs-sun orders will ship monday.
     
    Last edited: Jan 10, 2018
  3.  
    pop22

    pop22 Well-Known Member

    The efficiency is the difference between draw at the wall and the actual power provided to the cobs. As was stated, you have to measure the voltage and current drawn by the cobs with a meter to determine these numbers. My QB light draws 363 watts at the wall on a 320H-C2800B. The actual draw of the boards total is 340 watts so right about 94% efficiency.

    It will NOT draw 320 watts if you don't put that load on it, its a CC + CV driver, it only provides what the cobs want, ie, it won't try to sen 320 watts into a pair of cobs, it will send, say 36V @ the rated current, mine would send 2.8 amps to each 36V cob for 100.8 watts per cob, 201.6 for the pair. This is how constant current/constant voltage drivers work

     
    Last edited: Jan 10, 2018
  4.  
    nxsov180db

    nxsov180db Well-Known Member

    It'll provide whatever the COB wants voltage wise as long as it's in the voltage range of the driver yes, but the only thing that determines the wattage is the driver not the COB. The driver has no idea how much wattage your COBs are..
     
  5.  
    pop22

    pop22 Well-Known Member

    No, the cob determines the wattage consumed. Volts x Amps = watts. Undimmed, the C2800b I mentioned can provide 2.8 amps to each cob in series until the max voltage available is used by X number of cobs. so wattage would be based on a cob drawing 36V,
    36x2.8= 100.8 watts. so this driver would max at three cobs, based on both amperage and voltage, as the driver voltage range is 57-114 volts. So three cobs max.
    The drivers "wattage" rating is based on arbitrary best numbers. It means nothing other than that this is the rated max that Meanwell will offer warranty support to..

     
  6.  
    nxsov180db

    nxsov180db Well-Known Member

    We're both kind of right. I guess I should have been more clear. The driver will put out however many watts it wants to at a given voltage. A 36v COB could only be rated for 100 watts but if it is hooked up to a driver that puts out 200 watts at 36 volts it will receive all of those 200 watts.
    When you said that ^^^ it's not clear that you are only talking about voltage.
     
  7.  
    nxsov180db

    nxsov180db Well-Known Member

    I don't believe my unknown brand drivers do either after a little more testing. The driver I tested after disconnecting a 30 volt COB and wiring up to some 48 volt leds (driver maxes out at 46.5 volts) is pulling 205 watts at the wall but the other 3 unknown brand drivers are actually between 250-270 watts so the one driver that is only pulling 205 watts must have been a weak driver from the beginning. Before I disassembled these single COB/driver lights I measured a couple of them to see what the watt draw was as they claim 210 watts and the 2 I tested were right around that number but I must have had a weak COB/driver combo that probably only pulled around 160 watts initially..
     
  8.  
    pop22

    pop22 Well-Known Member

    Ahh, sorry, i missed it was a no name. Not telling what it will do then..lol

     
  9.  
    CobKits

    CobKits Well-Known Member Rollitup Advertiser

    COBs cant operate (far) off of their voltage/current curves, so what you say is possible but not likely with a properly selected driver
     
    1212ham likes this.
  10.  
    nxsov180db

    nxsov180db Well-Known Member

    So if I hook up a single citizen 1212 to a MW 320-36 the driver will only put out 100ish watts?
     
  11.  
    CobKits

    CobKits Well-Known Member Rollitup Advertiser

    which driver specifically?

    different results for A or B drivers

    B driver = all the driver's current at 36V = cob will take 1800 mA
    A driver = all the driver's current at 40V = cob will burn out immediately
     
    Last edited: Jan 10, 2018
    1212ham likes this.
  12.  
    nxsov180db

    nxsov180db Well-Known Member

    So if I hook up 1 Citizen 1212 to a MW 600H-36B it will only draw 1800 ma? The COB won't be immediately over powered and burn out?
     
  13.  
    CobKits

    CobKits Well-Known Member Rollitup Advertiser

    correct the driver will not go over 36V
     
    1212ham likes this.
  14.  
    nxsov180db

    nxsov180db Well-Known Member

    I'm talking about current.
     
  15.  
    CobKits

    CobKits Well-Known Member Rollitup Advertiser

    again at 36V the cob can only operate at one current. it cant possibly take more current at that forward voltage
     
    nc208 likes this.
  16.  
    CobKits

    CobKits Well-Known Member Rollitup Advertiser

    as an aside i just got my mind blown by my favorite band's lightshow.

    the new lights are like a giant cob with like 30 elements, each one is basically a spotlight pattern, is addressable and probably has RGB in each cell to make an infinite number of colors and patterns. ill upload a video when i see one and am curious to find out what fixtures they are
     
    SSGrower likes this.
  17.  
    nxsov180db

    nxsov180db Well-Known Member

    So the 600-36b would only provide 1800 ma even if only 1 single 1212 was hooked up to it? It wouldn’t blow or burn out the cob from pushing to much current through it?
     
  18.  
    ANC

    ANC Well-Known Member

    I just want to add something one needs to keep in mind. When driven at 100% load, drivers are most efficient. As we back down the power, driver efficiency falls by a few percent while LED efficiency goes up.

    When I decided between 4 and 3 strips for my lights I worked out efficiency at full and veg power, cost of the unit and how much money it would cost to run for a year.
    Looked at both options and I would take about a year on power alone to make up the cost of adding an extra strip. As I still need to cover more space with more light, at this stage the less efficient option is still the most efficient at getting the grow space completed.
     
    SSGrower likes this.
  19.  
    CobKits

    CobKits Well-Known Member Rollitup Advertiser

    yes you would be here on the driver output curve

    upload_2018-1-12_16-30-56.png
     
    pop22 likes this.
  20.  
    GrowLightResearch

    GrowLightResearch Well-Known Member

    You should also look at the economics of adding a strip and decreasing the current. The decreased current may allow you to add an additional strip increasing the total irradiance and decreasing the power consumption. The benefit being improved uniformity and possible reduction the distance between the fixture and canopy. The power savings from decreasing the distance and improved efficiency (lower current) can more than pay for the additional strip.
     
    pop22 likes this.

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