Black box doesn't dim to zero. Any way to fix this?

Discussion in 'Aquarium Lighting By Dana Riddle' started by Ben Weaver, Dec 20, 2017.

  1. Ben Weaver

    Ben Weaver Active Member Build Thread Contributor

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    Basicallywhat the title says. The dimmers work, they just don't dim very far... I specifically am looking to dim the white chanel farther. Can i buy a new dimmer or what would be the best way?
    Any help would be appriciated.
     
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  2. Jimmy Lee

    Jimmy Lee Well-Known Member R2R Supporter Build Thread Contributor

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    What leds do you have? Pics? Model number...
     
  3. Ben Weaver

    Ben Weaver Active Member Build Thread Contributor

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    Here are some pics 20171220_132725.jpg 20171220_132718.jpg 20171220_132709.jpg
     
  4. Jimmy Lee

    Jimmy Lee Well-Known Member R2R Supporter Build Thread Contributor

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    Those black boxes will only dim so far. It sucks. Im sure you can replace them dimmer if you wish but I would HIGHLY advise against it.
    I wouldn't personally take those apart and change the dimmer unless you are an electrification.
    Depending on what brand those are, they may be made of cheap quality and you risk catching your house on fire if you mess with them. (sometime even if you do not mess with them)
    Ocean Revive T247 will however dim from 0-100% on the white channel and blue channel.
    I know this is not the answer you wish to hear but it is the safest one.
     
  5. rushbattle

    rushbattle Active Member R2R Supporter

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    The driver won’t dim any farther. If you want it dimmer you need a new light.
     
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  6. RobertP

    RobertP Active Member

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    Agreed they only dim so low then you have to turn them off. I had my apex dimming them down to 10% then the next step was to turn it off. Never could set it any lower.
     
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  7. coil1002

    coil1002 Active Member R2R Supporter Build Thread Contributor

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    Changing the "dimmer" wont help. That actually only a Pot that adjusts the 12v signal into the driver. Most black boxes use 0-10vdc dimming signal drivers and the dimming on those drivers is not the best. If your handy and know what specs the led PCB is you can replace the drivers with mean well 0-5vdc divers they dim much smoother but by the time you do all that and build a voltage divider for the signal voltage you might as well buy a new light.
     
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  8. Ranjib

    Ranjib Valuable Member R2R Supporter R2R Excellence Award Build Thread Contributor

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    +1
    It's about the LEDs are wired , from my understanding. And even Kessil shows this, thought its specified they can be dimmable by 0-10V, they'll not turn on anything below 1V (on a80 & a360), and will cause blicking from 1-> 1.5v, and then dim smoothly from 1.5 to 10v.
    I might be missing many fine details (like pwm vs analog, current range etc, frequency variation etc etc), but I think the overall observations does not change that the control signal needs to be above a limit to start smooth dimming.

    This does not mean that the UX/UI (ant buttons, physical or in the web interface) will show it exactly like this.. they can map the acceptable range within 0-100% , without users being aware of the underlying logic
     
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  9. chipmunkofdoom2

    chipmunkofdoom2 Active Member R2R Supporter R2R Excellence Award

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    I think this has to do with how the LED driver behaves when you dim it. In this Reef Central thread, users discuss modifying the black box so that it can be Apex-controlled. Even when using a ADC to convert the digital dimming to the driver's analog 0v-10v signal, going below 10% just doesn't work.

    I think if you want to dim below 10%-20%, you're going to need to replace the drivers, which is probably not worth it on a $99 black box. For what it's worth, my black box registers about 6000lx a foot below the fixture at the lowest setting. Using a 60 conversion ratio, this is only 100 PAR at the very lowest setting, which is relatively low. Off the top of my head, I can't really think of a marine photosynthetic organism we keep in the hobby for which this is too much PAR. I would pick up a cheap lux meter to get an idea of the relative intensity of the light. It won't be a perfect measure of PAR, but it should give you an idea of how much light it's putting out at the lowest setting.
     
  10. Ben Weaver

    Ben Weaver Active Member Build Thread Contributor

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    Thanks everyone for the imput! Thats a lot a great info. I just wanted to clarify something. I Have another black box that dims as you all were saying, down to the last 10% or so then shuts off. The light it question doesn't go near that far. Im thinking that it dims maybe down to 40%? Is this still caused by a cheap driver?
     
  11. BarnacleBuster

    BarnacleBuster Active Member

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    Reading about DIY LEDs before on a cannabis site (no I dont, they have lots of info, Google "led" me there), I recall the use of a 10k ohm resistor inline to a 100k ohm potentiometer to limit the minimal dim to 10%. Something about preventing driver damage.. Meanwell (a driver company) recommends. Can't find source for that claim though, but alot of repeating about it.

    Maybe it is something simular?
     
  12. Mandelstam

    Mandelstam Well-Known Member

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    Just thought that I'd throw this out there when we're talking about Chinese made cheap electronics. If those power cords came with the light it might be a good idea to change them out. Bigclivedotcom brought this up in a video. Chinese generic power cord on the right, proper one on the left. Notice how they have been cheap on the copper and instead increased the insulation to make it look normal. Fire waiting to happen.

    Very funny and informative video though :D. Conclusion, if you want a Magic Wand, go for the original.
    upload_2017-12-20_23-19-46.png
     
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  13. Donovan Joannes

    Donovan Joannes Valuable Member R2R Supporter R2R Excellence Award Rest In Peace Build Thread Contributor

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    CBB that uses VR as dimming controller usually is fitted with 5v PWM or 0-10v dc daughter board. The small board where the knob is attached to is the controller.

    I owned a CBB before, and it uses 5v PWM controller. It doesn't dim all the way to off, but the knob is an off/dim type. Hooking the driver into an arduino enables 0%-100% dimming capability, and it's totally off at 0%, minimum dim level was 3% and maxed at 99%.

    I am not sure about OP lights, but with a slight modification it can be a good reef light.
     
  14. oreo5457

    oreo5457 Active Member

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    Could be drivers out of spec. I believe that inside the driver is a trim pot to adj the dimming (no, won't get to zero smoothly that way either)
    http://www.ultimatereef.net/threads/evergrow-led-controlled-with-arduino.713967/

    NO GUARANTEES though.. That pot was discusses "somewhere" in a hacking the Chinese black box thread..
    [​IMG]

    Exposed AC .. electrocution.. all that good stuff..

    Care to join?? I didn't..
    https://www.facebook.com/groups/603511806434292/
     
    Last edited: Dec 20, 2017
  15. Flippers4pups

    Flippers4pups Fins up since 1993 R2R Supporter Reef Squad R2R Excellence Award Build Thread Contributor

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    Yes, I believe the trim pot is the "blue box" in the photo. Could have just came mis-adjusted from the factory or it just won't adjust any lower.

    Yes, if not electricity inclined, warning! safety hazard, electric shock, discharging capacitors accidentally while charged.........etc. safety first!
     
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  16. Ben Weaver

    Ben Weaver Active Member Build Thread Contributor

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    Thank you guys, I'll definitely keep saftey in mind :) Sounds like ill have to break this thing open when i get a free minute!
     
  17. Ben Weaver

    Ben Weaver Active Member Build Thread Contributor

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    Just wanted to update and say thank you. Turning the little screw worked!
     
  18. oreo5457

    oreo5457 Active Member

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    YEA!!!!
     
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