Which DC Buck Converters?

Discussion in 'Power Supplies' started by BradsXmasLights, Jun 6, 2015.

  1. BradsXmasLights

    BradsXmasLights WiFi Interactive

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    Has anyone had experience with these Ray Wu - or similar - DC-DC Converters so I can drop 12V down to 5V at decent current levels?

    Reliability, performance?




    Going to rebuild my roof matrix (5V 2811B pixels) so it runs off 12V (or higher), so then the PSU's at a more serviceable height away from the wet/slippery roof
     
  2. multicast

    multicast Senior Elf Generous Elf

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    What is a decent level?
     
  3. multicast

    multicast Senior Elf Generous Elf

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    you can build an efficient and reliable Buck regulator with about $3 of parts..


    See schematic below.
     

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  4. AussiePhil

    AussiePhil Dedicated Elf Administrator

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    Had experience with both types P6060079.jpg


    Would buy anything less than the 50W ones but also wouldn't run them any harder than 60% load as the voltage regulation is not the best.


    I've had a couple of failures over the years but they seem tough as.


    The plastic ones i use inside controller cases to provide 5V power to boards.
    P6060074.jpg


    The metal ones get used everywhere else like on the P10 panel matrix here
    P6060083.jpg


    Cheers
     
  5. plasmadrive

    plasmadrive Full Time Elf

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    I usually order them from prodctodc.com. Less expensive.

    As for not loading them over 60%.. I use mine over 80-90% since the load is not constant and I have had no regulation issues ever. When I was testing them I ran them constantly at >90% and over a 48 hr period the regulation was great. On the 5v converters with 24v in the output drifted .1v-.2v from no load to full load.

    Remember, we are not doing lab experiments, we are doing Christmas lights. I use about about 40 of them for my show. I am adding another 20 this year

    Craig
     
  6. AussiePhil

    AussiePhil Dedicated Elf Administrator

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    Not so for us in australia though Craig and the ones brad is looking at are fully sealed.


    My experience with the Chinese ones is they can suffer voltage sag under higher loads so it's easier just to split the load up a bit more.


    whilst we may not be doing lab experiments a rock solid, non sagging 5v supply is essential for high quality pixel lighting. Every 0.1v is actually important and some of these will easily drop 0.5v and that can lead to pink pixels not white ones at high loads.


    Since this thread started Brad found this nice supply that looks ideal for larger P10 arrays, i have one in the cart for the next shipment from Ray.
     
  7. OP
    OP
    BradsXmasLights

    BradsXmasLights WiFi Interactive

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    My needs are two fold - 1) retrofitting/rebuilding my WS2812 5V Matrix with 12VDC power - just under 65A on paper but more like 50A iirc.... and 2) powering P10 panels.


    I found these LM2596S on ebay at $1.15 each - or one per P10 board, seems like a cheap way to get them all to 12V. What is unknown is if the switching on these will interference with the P10's


    Daryl also mentioned in chat that should a P10 panel loose power, it will attempt to draw power from it's neighboring panels via the data ribbon. Not sure what side effects we might have here especially in terms of troubleshooting? (I might also wiring my LED-sign up with status/power LEDs hidden away so I can easily tell that each regulator is running.)
     
  8. David_AVD

    David_AVD Good news, everyone!

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    Brad, I use those cheap little modules for powering small elements, but I'd never rely on them for something like a matrix.

    I know in theory you'd only be pulling about 1 Amp from each converter, but I think I'd use something beefier and power several panels at once from it.
     
  9. plasmadrive

    plasmadrive Full Time Elf

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    What do you mean "not so for us in Australia"? Do you mean the price? Is it cheaper to order those from Ray than Prodctodc down there? I think I paid about $6 for 5v@5amp fully potted converters. A bit more for 8amp and 10 amp. It looks as though Ray has changed his pricing from last time I looked. I do hate that his specs seems to be out of sorts all the time. (cut and paste errors I assume). All the converters I buy are potted making them waterproof.

    I have to say, I have not had any voltage drops of .5v under any conditions from 5v converters.... I did not take a scope out and look for transient drops, but with meters they were fine. (I know meters are slow), But I have had no problems with voltage drop at all for either color temperature shift or operational conditions with data handling. Most people get into voltage dropping trouble with wire size and length or trying to run too long of a strip on 5v. I put my converters pretty much right where they are needed and run 24v to them. I also limit the number of pixels in a string before adding a feed.

    So I guess the bottom line it good usage practices will help all around.
     
  10. plasmadrive

    plasmadrive Full Time Elf

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    I have about 50 of these sitting on the shelf. They were my first attempt at converters and pixels. They work fine but get hotter then hell with any real load. I agree that I would not use them on pixels unless it is a very small string of less than 1/2amp or so. I now use these to power the driver boards (e684, and so on) from the 24v buss. They work great for small loads and fit in the enclosures without taking up much space.
     
  11. EmmienLightFan

    EmmienLightFan One of few displays in the UK

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    I use some waterproof 12v-5v 3A regulators on my matrix. I actually use them with 9amps. I know I shouldn't, but after a several hour test they were barely warm.


    Also they are fully waterproof.
     
  12. Bill Ellick

    Bill Ellick Full Time Elf

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    I bought a couple of batches of those LM2596 regulators myself intending to use them for some elements but found that out of 20 of them, 6 had noise and trouble staying at set point. Also 3 other ones got pretty warm just sitting static with no load.
    I decided to just shelve them and went with prodctodc for my uses. They seem very stable and good but I have not gotten a chance to run them in a display yet and looks like I won't get to this year either but I would not recommend the LM2596 ones for much of anything at this point.
     

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