Simple, fast, efficient energy storage?

Discussion in 'The Projects Forum' started by JohnnyLaw, Jan 25, 2011.

  1. JohnnyLaw

    Thread Starter New Member

    Jan 25, 2011
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    I've been trying to figure out a way to absorb as much energy (within only minute or so) as possible from a 5V 1A, regulated, energy source. I'm going to discharge it on a 6v motor, I believe the free running current is 30mA.

    I'm leaning towards building a circuit with Super Capacitors but I feel that there might be a better way? Any advice, help, suggestions would greatly be appreciated.
     
  2. GetDeviceInfo

    Senior Member

    Jun 7, 2009
    1,571
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    use your motor to winch a wieght, then use the wieght to drive your load.
     
  3. JohnnyLaw

    Thread Starter New Member

    Jan 25, 2011
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    Hm, perhaps I didn't make myself clear enough.

    The motor itself is stationary and will be powered by the energy I stored. I will need to provide the energy through a circuit I designed. This circuit, which I am trouble trying to design, is what I'm actually focusing on. My question is what is a efficient way to obtain, store then discharge this energy (ie Super Capacitors?)
     
  4. Kermit2

    AAC Fanatic!

    Feb 5, 2010
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    They would be best if you plan to use the stored charge relatively soon after storing it. They lose charge quite fast through self discharge.
     
  5. wayneh

    Expert

    Sep 9, 2010
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    I'm pretty sure your cap idea is better than batteries, which are inefficient in returning the energy delivered to them.

    You might want to consider a voltage multiplier, so that the power stored is greater for a given amount of charge stored. This may allow for a smaller (cheaper) cap to store the same amount of energy. And, a higher stored voltage might help deliver more of that power back to the load. Otherwise, once the voltage drops too low, a lot of your stored charge will become useless. The multiplier will waste energy, but may increase end-to-end efficiency. If the stored voltage is too high for the load, I think you could use a DC-DC converter and still maintain pretty good efficiency.
     
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  6. JohnnyLaw

    Thread Starter New Member

    Jan 25, 2011
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    Thank you Wayneh, that was exactly what I was looking for. Anyway I can email you if I run into any other problems?
     
  7. JohnnyLaw

    Thread Starter New Member

    Jan 25, 2011
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    One more question, do super capacitors have accelerated leakage compared to regular capacitors? If so, usually how much faster?

    Since we need this bank to hold the energy for only a minute, we're unsure of how fast it will dissipate.
     
  8. wayneh

    Expert

    Sep 9, 2010
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    It's far better to keep things public here on the forum, where others can help and/or learn.

    I THINK (not sure) that leakage should be no problem for that time period. Minutes to hours or days, yes, but not for a minute or less. The specs of the cap should detail the self-discharge parameters.
     
  9. wayneh

    Expert

    Sep 9, 2010
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    Another idea popped into my head while I was out for a run tonight: I think you could use logic-controlled MOSFETS to charge a bunch of caps in parallel, or possibly in sequence, and when the 5v supply goes off, change the configuration to put the caps in series, giving you a boatload of charge AND voltage. The logic chips would take almost no power, allowing you ultimately to up the voltage without loss. Then you just need a DC-DC regulator to power the motor efficiently.
     
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