Ballast Tank Motor Relay & NiMh Question - Hunting for a 12v RC relay

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  • safrole
    Junior Member
    • Aug 2003
    • 272
    #1

    Ballast Tank Motor Relay & NiMh Question - Hunting for a 12v RC relay

    I just got my Robbe U-47 and a 750ml Engel piston tank. I know I could use an ESC to operate the tank, but I would prefer to use a relay, since there will be upgrades in the future that would be better suited by momentary full voltage. In any event I am trying to avoid rigging up a servo with a cam/microswitch setup which I foresee being less accurate when I'm "bumping" the tank to try to hover. Please tell me what I'm missing. I have a Futaba Skysport 6 (surface frequency).

    Another junior question...
    I bought two 3Ah NiMh battery packs. Does the physical size of the battery (C, sub-C) affect my battery endurance? I thought the amp hour rating was a rating of total capacity. So do smaller sized 3Ah batteries last about as long as larger 3Ah batteries?

    Thanks for your time,

    --Jason Overhulser
    Tags: None
    • raalst
      Senior Member
      • Feb 2003
      • 1229
      #2
      You are correct in that

      You are correct in that the Ah value (or mAh) is a measure
      of total capacity. it tells you the battery can deliver
      1 amp of current during X hours (3 in your case)
      or e.g. 2 amps during 1.5 hours. The more amps are
      consumed by the electronics, the shorter the battery
      lasts. sounds logical..

      The types and sizes of battery differ mainly in how fast they
      discharge when short circuited (do *NOT* do this).
      The rate of discharge is in Amperes (Amps) and
      high quality batteries can produce more amps than
      lower quality batteries (at any given time). So, high
      quality batteries are capable of discharging faster.

      This behavious is called internal resistance because
      it seems there is a resistor inside the battery limiting the
      amount of amps it can produce at any time.
      High resistance = low quality

      A perfect battery would in theory discharge in 0 seconds
      with gazillions of amps (and a large BANG undoubtedly)
      because there is no resistance in a (perfect) short circuit.
      Volts = Amps x Resistance, with Resistance = 0, the amps
      can go sky high.

      Regards,
      Ronald

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        • robse
          Junior Member
          • Mar 2003
          • 183
          #3
          Hi Jason..

          About the relay Q]http://www.graupner.com/index_neu.asp

          Hi Jason..

          About the relay Q]http://www.graupner.com/index_neu.asp[/url] ), and search for either type no, or stock no.
          For initial data, take a look at my page]http://hjem.get2net.dk/robse/SSBN/MyreSult.htm[/url]

          (Sorry for my spelling, but I'm about as tired as a complete retirement home..)

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