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Good hobbyist source for ultracapacitors?

Discussion in 'Electronic Components' started by Paul Ciszek, May 21, 2007.

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  1. Paul Ciszek

    Paul Ciszek Guest

    I am googling around for ultracapcitors/supercapacitors, and most pages
    want to sell me a prefab "power module" or "request a quote". Where is
    the best place to order unit quantities of ultracapacitors of various
    sizes for prototyping and general farting around with?
     
  2. Eeyore

    Eeyore Guest

    You need to go to component distributors. Most google seaches for ultracaps will
    return results for outfits selling upgrades for in car entertainment systems.

    Graham
     
  3. On Mon, 21 May 2007 19:18:00 +0000 (UTC), the renowned
    If you want the kind used for memory backup, try Mouser, Digikey etc.
    Maybe Jameco or some of the surplus places could have some too.

    If you're looking for the kind that have more oomph, you'll probably
    have more trouble unless you get lucky with surplus.


    Best regards,
    Spehro Pefhany
     
  4. VCRs, tv sets, likely some digitally tuned AM/FM tuners or stereo receivers
    to keep the memory alive while the unit is off. Perhaps some other
    consumer electronic equipment that likewise has settings you want to
    keep when off.

    I know I've found them in VCRs and tv sets.
     
  5. If you're in the US, Solarbotics.com do some nice ones: 1Farad at
    2.5volts.

    If, like me, you're in the UK, try Total Robotics:
    http://www.totalrobots.com/acatalog/Total_Robots_Capacitors_28.html
    Brendan Gillatt
    www.brendangillatt.co.uk
    GPG: 0x6E265E61
     
  6. Tolstoy

    Tolstoy Guest

    www.allelectronics.com
    has 1F 5.5 v caps for $3.50
     
  7. Paul Ciszek

    Paul Ciszek Guest

    Thanks. I finally found some on Digikey as well, searching on "capacitor"
    instead of "supercapacitor" or "ultracapacitor".

    Does anyone know how much "excess" you need on the voltage rating? If
    I have a PV module that might provide 12V peak and a load that can run
    at significantly less than that (voltage regulators, etc.) then what
    voltage rating do I need on the ultracapacitor?

    I am thinking I need about a Farad with a voltage rating of at least
    15V; nothing seems to exist in that range. However, at least one
    manufacturer says that you can string their ultracapacitors in series
    to get higher voltages (at a lower capacitance, of course). If I were
    using the ones Tolstoy describes, I would have to put three in series
    to get a voltage rating of 16.5V and a capacitance of 1/3 of a Farad,
    then put three of those strings in parallel to get 1 Farad.

    Does anyone know if it is better to put them in series first or in
    parallel first? i.e.,

    |-C-C-C-| |-C-| |-C-| |-C-|
    --|-C-C-C-|-- vs. --|-C-|-|-C-|-|-C-|--
    |-C-C-C-| |-C-| |-C-| |-C-|

    I am thinking that the latter is more likely to yield uniform voltage
    across all of the caps. Either one is a nuisance.
     
  8. (Paul Ciszek) wrote in
    I left off posting here till I knew whether you meant these, or the big
    oomphy things used in car sound systems...

    Electric Double Layer caps, GoldCaps (Panasonic brand). I also had trouble
    once finding some on Digikey till I knew what type they were called by. Now
    they group those with the aerogel, super and ultra all in one link it's
    easier.
    Regulate before the caps. I think you probably meant that but if not,
    you'll need to. Some kind of wide-ranging input DC-DC power converter..
    Either will do, but I'd favour the second. I've used the 1F and 0.33F
    2.5V types in parallel with a laser diode with no problems, the diode
    maintains a safe voltage of around 2.4, so you can operate close to limit.
    If you're wanting the full voltage, you might want to use the second
    network you drew, and across each set, a resistance. The value will have to
    be chosen by trial and error, I think, but each should be equal, to make
    sure the voltage is equally divided across the network. I think there is
    some internal DC leakage with these caps, and if it's unequal, you might
    get some capacitors seeing more voltage than others. If you omit the
    resistors, the connections in your second layout will be better, as they'll
    help to average out differences.
     
  9. Eeyore

    Eeyore Guest

    The cap's voltage rating needs at least to equal the peak voltage output.

    Graham
     
  10. legg

    legg Guest

    Mouser stocks Powerstor Aerogel Supercaps from Cooper-Bussman, with
    less than 100mOhm esr.

    Maxwell Technologies sells small quantities of supercaps in 'D' cell
    body sizes under the BCap or Boostcap trade name. These offer
    interestingly simple mechanical possibilities for retrofit.

    RL
     
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