12VDC @30AMP - 24VDC Conversion Needed

Discussion in 'General Electronics Chat' started by SEPHIRIOS, Aug 10, 2008.

  1. SEPHIRIOS

    Thread Starter New Member

    Aug 10, 2008
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    I'm runnung a project at 12vdc drawing around 30 amps and it works ok. when i hook 2 bat. in series it is much better. can anyone suggest a simple way to convert 12vdc to 24vdc directly as a 2 bat. application is not feesable due to space constraints.
     
  2. SIcam

    Active Member

    Aug 9, 2008
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    What size of 12 volt battery?

    What are your space constraints that you need to keep your size within? LXWXH
     
  3. SEPHIRIOS

    Thread Starter New Member

    Aug 10, 2008
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    I'm using an aoutomotive 12vdc bat. under the hood i do not have space for another bat hookup. I am looking to convert the 12vdc @ aprox. 30 amps to 24vdc.
     
  4. SIcam

    Active Member

    Aug 9, 2008
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    Is that direct conversion of power (Watts)? 24 Vdc @ 15 Amp = 360 Watts
     
  5. SEPHIRIOS

    Thread Starter New Member

    Aug 10, 2008
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    Yes that would be correct!

    pardon my frustration as to how something that sounds so simple can be so hard to get information on.

    I have been all over the internet and have found nothing but ps for sale and i dont want to buy one. could this be as simple as using a microwave transformer?
     
    Last edited: Aug 10, 2008
  6. SIcam

    Active Member

    Aug 9, 2008
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    DC does not upconvert voltage levels easily. You either start with the correct voltage or you need to switch the pulsate the voltage and use a transformer to increase the voltage. Your best bet is to use a second battery but since your space is limited then you will need to to get a DC to DC convertor. http://www.powerstream.com/dc24.htm

    Another option is to get a dc to ac Power inverter then use a transformer and a bridge rectifier with some filtering to get back to 24Vdc but this can get messy.

    What are you trying to drive with the 24 volts?
     
  7. SEPHIRIOS

    Thread Starter New Member

    Aug 10, 2008
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    If I were to use an an inverter what size diodes would i use for the bridge. not to worried abou the ripple voltage.

    I'm experimenting with some unconventional electrolyzer circuits
     
  8. SIcam

    Active Member

    Aug 9, 2008
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    Please understand that if your car has a 100 Amp alternator and you devote 30 Amps continuously to another function you effectively reduced your alternater dramatically. This means that you will need to spend at least (most likely more) 360 watts of energy to replenish the energy you used in your experiment. If you do not replenish this energy (recharge your battery) you will be parked along side the road when your battery goes dead.
    Do you know why it is recommended to always connect the ground cable away from the battery on the frame of the vehicle when jump starting a car?
     
  9. SEPHIRIOS

    Thread Starter New Member

    Aug 10, 2008
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    i am fully aware of the requirements of my endeavor . I really am just trying to find out how to get 24v from 12v . So far ive got an inverter to use and need to find what size diodes to use in either a half wave or full wave rectifier?
     
  10. SEPHIRIOS

    Thread Starter New Member

    Aug 10, 2008
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    TY. but in english please its been 30 yrs since basic electronics for me. any values ou could recommend:confused:
     
  11. SgtWookie

    Expert

    Jul 17, 2007
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    OK, what is the output of your inverter? Voltage and current rating?
     
  12. PackratKing

    Well-Known Member

    Jul 13, 2008
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    Lean toward overkill on your diodes. At least double your PRV, and 4X [ quadruple ] your forward max current.

    A nice heatsink w/ a muffin fan on it may be a good foundation for your diodes if you use a monolithic full-wave bridge.[ 4 diodes potted in an inch-square x 1/2 " thick plastic casing, with a built-in heatsink plate, with a central hole to bolt it to a larger heatsink ]

    In making a rectifier for a small 110v "buzz-box" arc welder, I ganged 6 -- 400 PRV 25 Amp bridge [ large square radio shack ] rectifiers, and let Ohms' law take care of the apparent amperage overload.

    Crude, but it works well at 40 amp limit. DC welding rocks !!
     
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