Potential Difference Between 12V Battery Terminals

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Discussion Overview

The discussion revolves around the potential difference between the terminals of a 12-volt battery when it is short-circuited. Participants explore the implications of this scenario, including the behavior of the battery under such conditions.

Discussion Character

  • Exploratory, Technical explanation, Debate/contested

Main Points Raised

  • One participant states that the battery will discharge quickly, leading to a voltage drop from 12 volts to 0 volts.
  • Another participant proposes a model of the battery as an infinite current source with 12 volts in series with its internal resistance, suggesting that the shorting wire also has resistance that affects the voltage at the terminals.
  • This participant further explains that the finite nature of the battery's current supply will eventually lead to a voltage drop to zero as the battery discharges.
  • A question is raised regarding whether the discussion pertains to a standard automotive 'short circuit' battery test.

Areas of Agreement / Disagreement

Participants express differing views on the behavior of the battery during a short circuit, with no consensus reached on the specifics of the voltage drop or the implications of the model proposed.

Contextual Notes

The discussion includes assumptions about the internal resistance of the battery and the resistance of the shorting wire, which may not be explicitly defined. The model of the battery as an infinite current source is also a simplification that may not account for all real-world factors.

khamaar
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A 12 volt battery is short circuited. what would be the potential difference between its terminals?
 
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The battery will discharge quickly and the voltage will drop quickly from 12 to 0. After that, the voltage will be zero.
 
In a little more detail...

You can model the battery as an infinite current source with 12v potential in series with a small resistance (this is the battery's "internal resistance"). The wire or whatever you use to short the battery terminals also has some small resistance -- unless you have invented a room temperature super-conductor. If you know those two resistances you can calculate the voltage divider drop at the battery terminals.

Then you need to realize that the "infinite current source" is actually finite and can only provide a fixed number of electrons...just like a tank of water. So, as timthereaper says, the voltage at the source will start to droop and eventually become zero when there's no more water in the tank.
 
Is this an automotive question and are you talking about the standard automotive 'short circuit' battery test?
 

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