Capacitor bank charging help

Discussion in 'General Electronics Chat' started by Joeshmoe, Jan 12, 2007.

  1. Joeshmoe

    Thread Starter Active Member

    Jan 12, 2007
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    Hi im working on a project and I need to charge a capacitor bank to about 5000uf at 200V I would like it to charge quikley and I was thinking about a boost converter but I dont have an extencive amount of knowledge about circuts. I found skematics like this http://4hv.org/e107_files/public/1147309245_186_FT0_boost_converter4a.jpg
    and similar ones but I was wondering if it were possible to make one with parts from radio shack. If its not possible to make a boost converter from radio shack parts is there antoehr way to make a quick cap bank charger.
     
  2. beenthere

    Retired Moderator

    Apr 20, 2004
    15,815
    282
    Hi,

    How much bulk are you willing to accept? A transformer with a secondary output of about 140 volts will charge your capacitors, limited only by the current-carrying capacity of the secondary. A transformer and rectifier can recharge the capacitor in milliseconds, if you don't mind dimming the room lights briefly.

    Is this a photoflash application, and what is "quickly" defined in a time period?
     
  3. Joeshmoe

    Thread Starter Active Member

    Jan 12, 2007
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    Now that I think about it I guess it would be best to make 2 chargers one that can use a wall outlet and one that uses batteries. For testing I can use the outlet and dont mind bulk. I guess when I say quickly I mean in seconds. I Also dont want to draw huge spikes of current from the wall because the breaker is old and will blow fairly easily and unfortunately I do not have access to it. So I guess I want a balance between charging speed and the amount of current drawn.
    Right now I am using a disposable camera cap charger. I dont like this for a few reasons. One it takes a few minutes to charge the bank. Two the voltage is higher that 200V which i know is not good and because I have too use a multimeter to make sure it stops charging before 200V. These are not photoflash caps.
    Ultimately I would like to make it battery powered but for battery power I do care about bulk.
     
  4. beenthere

    Retired Moderator

    Apr 20, 2004
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  5. Joeshmoe

    Thread Starter Active Member

    Jan 12, 2007
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    I looked around the TI link and cant find the cap charging constraints article. I have tried googling "photoflash chargers" before and just tried again and what im looking for is if it is possible to to charge the cap bank using parts from radio shack. Also the photoflash chargers are not build to charge a 5000+uf cap bank.
     
  6. Spoggles

    Well-Known Member

    Dec 2, 2005
    67
    0
    Would you be OK with 150V? You could half rectify the wall 120v and use a light bulb (100W) as a current limiter. Also, you would know when the bulb is no longer emitting photons, that the caps are charged.

    Spoggles
     
  7. Joeshmoe

    Thread Starter Active Member

    Jan 12, 2007
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    0
    i guess 150v is ok for now but i am not 100% sure how to make that circut and i dont want to go messing around with 120v AC. 200V is perfered but i can start with 150v. thanx
     
  8. italo

    New Member

    Nov 20, 2005
    205
    1
    you need a sensor that tells you ac input is at peak voltage then close a switch. at this time there is max power available. otherwise you must wait for the power to be available before you do anything.
     
  9. Joeshmoe

    Thread Starter Active Member

    Jan 12, 2007
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    0
    i dont quite understand what you mean can you elaborate?
     
  10. coil_man

    New Member

    Jan 10, 2009
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    i was using a similer set on my bank no light buble and i blew a breaker ):
     
  11. Alberto

    Active Member

    Nov 7, 2008
    169
    36
    Use a bridge rectifier and a filament lamp in series to the AC line (200 watts)

    If you connect it to your bank and plug into the main (120 ac) you should obtain 170 Volt dc in few seconds.

    Higher the wattage of the lamp shorter the charging time.

    Alberto
     
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