Are all capacitors created the same?

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  • FE Wannabe
    Senior Member
    • Jul 2007
    • 626

    #1

    Are all capacitors created the same?

    Hello all,

    I was going to add the Etti cap board to my Etti 150, but I do not have enough room in my N2 Sport Hydro. So I figured I would just add a few axial capacitors between the positive and negative battery leads feeding the ESC.
    I noticed the 35V 470uf caps on the Etti ESC are about a 1/3rd in size to the other axial or radial 35V 470uf caps from other manufacturers like Rubycon or Xicom.
    So my question is - Do all 35V 470uf caps have the same capacity to protect my ESC or are the larger ones more capable?

    I see that the Etti cap board contains 10ea of the 35V 470uf smaller caps.
    Would I have to add 10ea of the larger Rubycon 35V 470uf caps to match the capabilities of the caps on the Etti or would a smaller number work?
    I know more is better, but do I need 10ea of them to protect an 7.4V N2 Sport Hydro?
    I have heard that the larger 35V caps like the 1000uf and 2200uf have a higher resistance than paralleling a bunch of smaller caps, so I assume that is not the best way to go either. I am just trying to figure out the best way to go with my limited real estate.
    Any info would be appreciated.
    Thanks,
    Brad
    SoCal Fast Electrics|H&M Drifter S-CC1512/4S/T180A|Aeromarine Scorpion 32"- UL-1/4S/HM200A|Insane 34- CC1515 1Y/4S2P/T180A|BK Bandit S-CC1515 1Y/4S2P/T180A|Insane FE30 UL-1/4S/ETTI 150
  • domwilson
    Moderator
    • Apr 2007
    • 4408

    #2
    Not all caps are the same. Some have a lower Equivalent Series Resistance (ESR) than others. In addition, there are various tolerances. Generally, the larger caps dissipate more heat than the smaller caps...But I do stress...Generally. Putting a few caps in parallel will lower the ESR and increase total capacitance. If you are using decent caps, I don't see a problem as some have already used Radio Shack caps on their ESC's with success. But I would go with a little higher voltage and temp range.
    Government Moto:
    "Why fix it? Blame someone else for breaking it."

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    • FE Wannabe
      Senior Member
      • Jul 2007
      • 626

      #3
      Thanks for the response Dom,

      So you are saying that you can run larger voltage caps than 35V, like 50V without any issues?
      I will definitely only look at low ESR caps with high temp ratings.

      Is there any rule of thumb for how much capacitance to add for the amount of expected amp draw or voltage applied?

      Thanks,
      Brad
      SoCal Fast Electrics|H&M Drifter S-CC1512/4S/T180A|Aeromarine Scorpion 32"- UL-1/4S/HM200A|Insane 34- CC1515 1Y/4S2P/T180A|BK Bandit S-CC1515 1Y/4S2P/T180A|Insane FE30 UL-1/4S/ETTI 150

      Comment

      • domwilson
        Moderator
        • Apr 2007
        • 4408

        #4
        Not that I'm aware of.
        Government Moto:
        "Why fix it? Blame someone else for breaking it."

        Comment

        • FE Wannabe
          Senior Member
          • Jul 2007
          • 626

          #5
          Thanks.
          SoCal Fast Electrics|H&M Drifter S-CC1512/4S/T180A|Aeromarine Scorpion 32"- UL-1/4S/HM200A|Insane 34- CC1515 1Y/4S2P/T180A|BK Bandit S-CC1515 1Y/4S2P/T180A|Insane FE30 UL-1/4S/ETTI 150

          Comment

          • questtek
            Senior Member
            • May 2009
            • 556

            #6
            Before you buy any see me and I believe I can help you out on the caps....as well as the 6 mm bullets. Joe

            Comment

            • FE Wannabe
              Senior Member
              • Jul 2007
              • 626

              #7
              Originally posted by questtek
              Before you buy any see me and I believe I can help you out on the caps....as well as the 6 mm bullets. Joe
              Thanks. Joe! I will pm you in a while about the caps as well. I love one stop shopping!
              SoCal Fast Electrics|H&M Drifter S-CC1512/4S/T180A|Aeromarine Scorpion 32"- UL-1/4S/HM200A|Insane 34- CC1515 1Y/4S2P/T180A|BK Bandit S-CC1515 1Y/4S2P/T180A|Insane FE30 UL-1/4S/ETTI 150

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