14-15vdc 20a power supply

Discussion in 'General Electronics Chat' started by liamneeson248, Jan 11, 2016.

  1. liamneeson248

    Thread Starter New Member

    Jan 11, 2016
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    1
    First of all sorry for my bad english because its not my first language.
    I want to create a 220V AC to 14V DC 20A power supply to charge my Lead Acid 12V(200AH) battery.
    i know 4-5 A is enough to charge it normally but after using it for 4-5 months user need to charge it on higher Ampere to maintain battery gravity.
    so any circuit diagram or any other help will be appreciated
    Thank you in advance,
    Peace.
     
  2. tcmtech

    Well-Known Member

    Nov 4, 2013
    2,034
    1,645
    Go buy a common 20+ amp automotive battery charger.

    Unless you can get the correct size and voltage transformer and rectifiers for free you wont build a battery charger for less than you can buy one.
     
    MikeML likes this.
  3. liamneeson248

    Thread Starter New Member

    Jan 11, 2016
    14
    1
    so your suggestion is that i should buy a branded one,not build my own ? why! is it so hard to make ?
     
  4. #12

    Expert

    Nov 30, 2010
    16,268
    6,780
    It' is not so hard for me to make, but I just make a DC power supply and watch carefully as it charges the battery. Most other people want their battery charger to know when to stop, or do 3 stage charging. That can be fairly simple or fairly complicated. You have not said much about what you want, except that you explained that you don't know about standard charging rates and why they should decrease as the battery gets old.
     
  5. dl324

    Distinguished Member

    Mar 30, 2015
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    If you need to ask for help, there's a good chance that your desire exceeds your ability.

    There's also the fact that a high volume commercially available charger would cost less than building your own.
     
  6. liamneeson248

    Thread Starter New Member

    Jan 11, 2016
    14
    1
    Yes i know but i have a plan to build that charger on one pcb with a microcontroller so that's why i can't afford to have charger attached differently from main pcb because its gonna cost me more space and problems so thats why i need to make it on required pcb board.
     
  7. Dodgydave

    Distinguished Member

    Jun 22, 2012
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  8. liamneeson248

    Thread Starter New Member

    Jan 11, 2016
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  9. Dodgydave

    Distinguished Member

    Jun 22, 2012
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    So use a 20A transformer and bridge rectifier, ok.
     
    absf likes this.
  10. dl324

    Distinguished Member

    Mar 30, 2015
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    Also note that that "charger" has no voltage regulation or timers.

    Here's an article on how to charge lead acid batteries.

    For US$30, I can buy a 10A charger that turns itself off when the battery is fully charged. All nicely packaged. I know how to design and build one, but if I can buy one for $30, it's not worth the time or effort.
     
  11. crutschow

    Expert

    Mar 14, 2008
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    3,229
    The transformer should be derated at least 40% if you want 20Adc into a battery, due to the high peak RMS current through the rectifiers, thus the transformer RMS current rating should be at least 30A.
     
  12. liamneeson248

    Thread Starter New Member

    Jan 11, 2016
    14
    1
    Thank you so much for help guys now i understand it better than before i hope it will help me in my project
     
  13. AnalogKid

    Distinguished Member

    Aug 1, 2013
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  14. crutschow

    Expert

    Mar 14, 2008
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    Certainly if there's nothing to limit the charging current.

    Okay, I'll bite.
    Whats the 1st?
     
  15. AnalogKid

    Distinguished Member

    Aug 1, 2013
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    No ammeter. 0.01 ohm is better than nothing.

    ak
     
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