Power Supply

Discussion in 'General Electronics Chat' started by aq_rules, Mar 15, 2010.

  1. aq_rules

    Thread Starter Member

    Oct 28, 2009
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    I want to make a power supply equivalent to 12VDC 200Ah of a battery..


    AND ANSWER THE SECOND QUESTION AFTER THE FIRST ONE

    2nd question:
    "How many UNITS of MAINS does the charger of 12vdc 180 or 200 ah consumes?"

    It takes load more than a 220VAC 40w fan?
     
  2. SgtWookie

    Expert

    Jul 17, 2007
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    You want to make a power supply equivalent to a battery? Or a charger FOR a battery?

    There is a link to a 12v battery charger project I posted in your other thread.

    A 12v battery stores a LOT of energy; it can output several hundred amperes for short periods of time. It would be very difficult, and very expensive to design and build a power supply that could mimic that kind of performance.

    You don't get back everything you put into charging a battery. If you had a charger that was 100% efficient (not possible) then you would get back about 70% to 80% of what you put into a battery.

    The charger efficiency itself is another story; it all depends on how the charger was designed and built. The one that I posted a link to is certainly not state-of-the-art, but it's probably not too bad, either.

    It is desirable to charge standard lead-acid batteries at a fairly slow rate. If you charge them quickly using high current, they will become heated internally. The hotter they are inside, the more chemical activity, and the shorter their life. It takes a long time for a battery to cool off once it has been heated up.

    5A to 6A is a good maximum charging rate for an automotive battery. After it has been charged to 14v-14.5v, the battery should be charged in the 13.3v-13.8v range, depending on battery chemistry, construction, and internal temperature.
     
  3. aq_rules

    Thread Starter Member

    Oct 28, 2009
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    Thanks wookie...:D
     
  4. aq_rules

    Thread Starter Member

    Oct 28, 2009
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    its a power supply i'll not use any kind of batteries...i want to check my Inverter's perfomance buy connecting this supply which will be acting as a battery..

    I couldn't afford the battery these days...but m curious to see tht my inverter works or not...:)
     
  5. SgtWookie

    Expert

    Jul 17, 2007
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    I don't know what part of the world you are in, so I don't know what you expect out of your inverter. Putting your country and state or province or region is a good idea.

    Let's say that you think your inverter can produce 250 Watts at 220 Volts.
    That's I=P/E= = 250/220 = 1.1363... Amperes at 220 Volts.

    Suppose that your inverter is 70% efficient. If it's a really simple inverter, it's probably less efficient than that.

    220v/12v=18.333...
    1.1363/70% = 1.5151
    1.5151 x 18.333 = 27.78 Amperes that you will need from a 12v power supply to get 250W at 220V.
     
  6. aq_rules

    Thread Starter Member

    Oct 28, 2009
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    my inverter can produce 1250w...
     
  7. aq_rules

    Thread Starter Member

    Oct 28, 2009
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    tht means 148.81 amperes??
     
  8. aq_rules

    Thread Starter Member

    Oct 28, 2009
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    i live in Karachi,Pakistan
     
  9. SgtWookie

    Expert

    Jul 17, 2007
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    You would need about 138.9 Amperes at 12v continuously for a 1250W inverter that is 70% efficient.

    In order to power the inverter for a period of 10 hours, discharging a bank of batteries no more than 50%, you would need about 7,000AH of capacity, or 35 of your 200AH batteries.
     
  10. R!f@@

    AAC Fanatic!

    Apr 2, 2009
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    It figures :).
    Power surges and black outs are common in rural areas
     
  11. aq_rules

    Thread Starter Member

    Oct 28, 2009
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    ummm...no i waz wrong its not 1250W it's 1250VA
     
  12. Wendy

    Moderator

    Mar 24, 2008
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    VA is Volts Amps

    1250VA / 12V (battery) = 104Amps.

    Instead of powering the whole house with one big battery bank, figure out the critical components in the house you want, then power them separately.
     
  13. aq_rules

    Thread Starter Member

    Oct 28, 2009
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    no i just want to check my UPS through a powersupply...i dun want to run my entire house with it...just wanted to check its performance...
     
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