i need to build or buy

Discussion in 'The Projects Forum' started by rbs75, May 11, 2014.

  1. rbs75

    Thread Starter New Member

    May 11, 2014
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    i have a 24v 1500 watt 75a power supply, i would like to regulate the output from lowest voltage possible to highest voltage possible and have linear control of the output. any help would be awesome.

    thanks
     
  2. #12

    Expert

    Nov 30, 2010
    16,284
    6,797
    Start with about 72 power transistors and about 65 to 114 CFM of forced air flow and adjust to your local conditions.
     
  3. rbs75

    Thread Starter New Member

    May 11, 2014
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    yeah, thanks
     
  4. #12

    Expert

    Nov 30, 2010
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    OK. You have shown that you aren't just a passing impulse poster that will never come back for the answers.

    What do you want? A schematic?
    Is this just a voltage regulator? Need current limiting? How accurate? Do you already have the transformer and filter section? What voltage comes out of your wall outlets? Is it one polarity only or a +/- supply? Need voltage meters or current meters? What country are you in? Where can you buy parts?

    etc.
     
  5. rbs75

    Thread Starter New Member

    May 11, 2014
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    im skilled enough to build what you give me, just not enough to figure it out on my own. i just need some help, i cant find exactly what i need, so i know i may need to make it myself.
     
  6. rbs75

    Thread Starter New Member

    May 11, 2014
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    im building a charging station for myrc batteries, i need output fro 12-24 volts or more if possible, i would like to transform the extra watt amps to voltage also, i.e. range from 5v @1000watts to 50 volts @25amps.
     
    Last edited: May 11, 2014
  7. rbs75

    Thread Starter New Member

    May 11, 2014
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    just running chargers off the powers supplies, but the operating range i need is 12-40 volts with the rated 1400 watts and 100 amps @24 volts i have
     
  8. rbs75

    Thread Starter New Member

    May 11, 2014
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    well. 48v may be the high end that i need
     
  9. inwo

    Well-Known Member

    Nov 7, 2013
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    I'll have to agree with #12 in post #2.

    What type of power supply are you starting with?

    Doesn't seem practical to boost 24vdc to 48vdc.

    Seems a simpler method is building a 0-48 volt charger from scratch.
     
  10. rbs75

    Thread Starter New Member

    May 11, 2014
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    ok, if what i want isnt possible, what is? lets say 12-24 volt with the output that i have
     
  11. ronv

    AAC Fanatic!

    Nov 12, 2008
    3,290
    1,255
    Most people do what it looks like you are doing in the picture and just "stack" some big old server power supplies. I'm guessing your batteries are over 24 volts and that is why you need the higher voltage?:confused:
     
  12. #12

    Expert

    Nov 30, 2010
    16,284
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    To get 12V to 24V @ 100 amps in a linear supply, I'm coming up with a transformer rated at 3871 watts. 24V rated, 161 amps, with a full wave bridge. Does anybody know where to buy 4Kw transformers or how many hundreds of dollars they cost?

    And again I ask, what country is rbs75 in?
    The shipping costs are going to be noticeable.
    With a switching supply, 100 amps at 5 volts is going to be a lot less expensive.
    You can find 500 watt computer supplies for around $160 to $230. A 4000 watt transformer is going to cost more than that, and then there are the transistors and heat sinks to buy.
     
    Last edited: May 12, 2014
  13. rbs75

    Thread Starter New Member

    May 11, 2014
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    I'm in the us, some chargers require up to 40v @1000w. Sounds like I just need to deal with having 2 12v channels and 1 24v channel. But it would be nice to be able to just run them in series and be able to adjust output from 0-24 volts.
     
  14. rbs75

    Thread Starter New Member

    May 11, 2014
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    Or to up step the voltage to 48v
     
  15. Papabravo

    Expert

    Feb 24, 2006
    10,142
    1,790
    You're still missing the essential point. Dealing with high power levels presents a number of unique circuit design and implementation problems.

    #1 DC-DC conversion will almost always be more challenging than starting with mains voltage and building the supply you want.

    #2 When you have an adjustable linear supply at high currents you need to dissipate and get rid of enormous amounts of heat to avoid literally cooking your components.

    #3 Don't put your lips on a component with a junction temperature of 125° C. You will burn them painfully.

    Think about these points and tell us you understand.
     
  16. rbs75

    Thread Starter New Member

    May 11, 2014
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    Ok, no problem
     
  17. Brownout

    Well-Known Member

    Jan 10, 2012
    2,375
    998
    It's possible. How much current do you thing you'll need for your charger? Surly you don't need the full 75a. Here are ways to do this, some aren't efficient, but that might not matter to you.
     
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