Low Resistance and but Not Exploding Batteries

Discussion in 'The Projects Forum' started by yono, Jul 26, 2015.

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  1. yono

    Thread Starter New Member

    Jul 26, 2015
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    I'm working on a project that involves a D Cell battery. The circuit is basically a short circuit considering it's mostly just a wire connected to both terminals of the battery. I would like to get as much current as possible from the battery into the circuit, so I did not add any resistors to the circuit. WOAH no resistors!!!! This being said, I want to avoid the battery overheating and exploding. How would I go about doing this?
     
  2. MaxHeadRoom

    Expert

    Jul 18, 2013
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    You should not be loading the battery any more than it is capable, based on its mAhr rating.
    Max.
     
  3. #12

    Expert

    Nov 30, 2010
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    When you short a battery, all of its energy is dissipated by its internal resistance. If you have ever put a 9 volt battery in your pocket with some coins, you will know that result! A D battery has a lot less voltage and a lot more surface area. You stand a chance of it not exploding, but I would do some measurements before I took my goggles off. First problem: I am afraid the short circuit current will be more than 10 amps and I am not willing to risk a $6 fuse in my meter to test this theory.

    I did provide a setup for a child's school experiment once. Several D batteries in parallel with a 0.3 ohm, 25 watt resistor in series. The intent was to use 5 amp pulses on an electromagnet. The child survived. I never got my resistor back. :mad:

    Anybody here ever blow up a D cell?

    ps, a car battery will certainly go into convulsions if you short it.
     
  4. DickCappels

    Moderator

    Aug 21, 2008
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    You can do that by using a very long piece of wire so its resistance is enough to keep the battery operating at a safe temperature.

    If you tell us what your objective is, if anything beyond making a battery hot, you will probably receive some suggestions that are more helpful.
     
  5. crutschow

    Expert

    Mar 14, 2008
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    How long do you intend to apply this short to the battery?
     
  6. yono

    Thread Starter New Member

    Jul 26, 2015
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    From 2 to 2 and a half hours. Would there be some way to heat sink the system, or is the heat not necessarily what would cause the battery to explode?
     
  7. #12

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    Nov 30, 2010
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    According to my charts, an Alkaline D cell will fire into a 1/2 ohm resistor for 2 hours as its voltage decreases to 0.7 volts (1.4 amps). If you short it, it will not last for 2 hours!

    You are trying to do the impractical and the results will not comply with your wishes.
     
  8. yono

    Thread Starter New Member

    Jul 26, 2015
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    For any given full amount of time that the battery will last being short circuited, how do I prevent the battery from exploding during that given amount of time?
     
  9. #12

    Expert

    Nov 30, 2010
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    Nobody has ever, "rated" a D cell into a direct short, therefore, there is no look-up table. I calculate 72.6 watts in the first minute. I think that will be enough to boil the water inside the cell and rupture the case.

    Forum rules forbid me recommending any procedure that is obviously dangerous. This is obviously dangerous. I expect this is the end of this thread.
     
  10. yono

    Thread Starter New Member

    Jul 26, 2015
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    Ok
    OK, so it's simply a matter of reducing the heat that makes its way to the battery? Yes, it is very dangerous, and to anyone reading this, I do not recommend directly shorting a battery. This is all hypothetical.
     
  11. DickCappels

    Moderator

    Aug 21, 2008
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    Since no information about your intended use is forthcoming and there is a strong possibility of danger this thread is locked.
     
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