Capacitor bank - charger

Discussion in 'General Electronics Chat' started by Huby, Aug 14, 2012.

  1. Huby

    Thread Starter New Member

    Jul 5, 2012
    24
    1
    Hi.

    I want to charge my capacitor bank with 48V-25A DC source.

    The idea is to store 1KW in this capacitor bank and then to use this
    power to run some 300V electronics.

    DC source is constant so capacitors can be "recharged" all the time.
    The capacitor bank should be made of 300V capacitors and normal power consumption of our electronics is around 800 - 900W.

    Does anyone has some DIY project on this or maybe some guide how to start ?

    Regards !
     
  2. MrChips

    Moderator

    Oct 2, 2009
    12,446
    3,362
    It always helps to give us the big picture. If it is something we shouldn't hear about then we don't want to know about it.
     
  3. praondevou

    AAC Fanatic!

    Jul 9, 2011
    2,936
    488
    Do you mean 1kWh?

    You want to "run" 300V electronics. Then you need capacitors with a higher rated maximum voltage (like 400V for example).

    You need a boost converter to go from 48VDC to 300VDC.

    From your other very recent posts it is not clear what you are trying to build. Are these all different projects?
     
  4. Huby

    Thread Starter New Member

    Jul 5, 2012
    24
    1
    This are different projects but it better to finish the first one before start with the new one. I will reopen this post in few weeks.
    It's better this way but anyway thank you for help.

    btw. now when you mention the active project...
    Can this capacitor approach be used for my dc/dc project ?
    ---------------------------------------
    e.g. if i dismantle some 12/220 - 2kw - DC/AC converter and if i measure voltage on exit capacitor i will get around 250V. I tested this.
    ---------------------------------------
    Can this approach be used to charge some capacitor bank and get the kw range ?
     
  5. crutschow

    Expert

    Mar 14, 2008
    13,016
    3,235
    Even small capacitors can deliver kw for a a short time. The question is now long do you need this kw load to run from the capacitors and what voltage drop can you tolerate while the capacitors are discharging? That determines the size of the capacitors you need.
     
  6. Huby

    Thread Starter New Member

    Jul 5, 2012
    24
    1
    When i was starting with this idea I firstly connected 2x 2KW DC/AC - 12/220V converters ( galvanic separated ) and it worked OK.
    I got 470V out of them and power was around 2kw.

    When i connect this 470V to my electronic it worked like a charm.
    (btw. this is now description of second project but we started so let's continue with this.)

    The circuit was drawing from 500 - 1,8KW ( motor was connected to this circuit ).

    Then i was thinking, damn, there must be a way just to change the output capacitor and rectifier to make single output without wiring two converters together. So my next plan was to buy some 72V DC/AC inverter and to do just that. Change the capacitor and rectifier part.

    Then i stuck in process of finding one 72V - 6 or higher 8 KW inverter.
    Only converters that i found ware 12 0r 24. But ok i can go with 24
    --------------
    To answer your questions:
    How long do you need this kw load to run from the capacitors
    - capacitor should power this 450 circuit (motor controller) all the time.

    What voltage drop can you tolerate while the capacitors are discharging?
    - range is quite big. Input of this controller can accept any dc range between 420 - 500VDC.
    --------------
    Should i go into DC/AC converter modification.
    Or better, how to "set/prepare" the rectifier part ?
     
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