3
$\begingroup$

I've been thinking about this, and my answer is leaning towards yes, but I couldn't find any definitive answer by Googling.

If the higher potential side of a typical battery is connected by wire to a spike driven into the ground, will it eventually deplete?

My thought process is that the voltage difference will cause current to flow between the electrode and the earth, causing the battery to eventually "die," just as if it was connected in a circuit.

However, I also wonder what the difference is between this situation and shorting the battery. Connecting the anode and cathod of a battery together will cause it to heat up and damage itself, but will the same happen if its connected to ground? Isn't it (physically) the same situation?

$\endgroup$
  • $\begingroup$ "My thought process is that the voltage difference will cause current to flow" - what voltage difference? If you connect one terminal of the battery to the Earth, there is no voltage difference between that terminal and Earth. Yes, there is a voltage difference between the other, unconnected terminal but, since it is unconnected, there is zero current in or out of this terminal. How could there be a discharge current? $\endgroup$ – Alfred Centauri Dec 17 '16 at 0:32
2
$\begingroup$

Here is the thing about potential/voltage. Potential/voltage is a measure of difference in the, say, potential energy between two points in space. So the correct term is actually: "potential/voltage difference" when we talk about that stuff. So when you talk about batteries, the higher potential side of the battery is higher, with respect to, the lower side. It has nothing to do with anything else, you, me, your computer, the Sun or Earth. Technically, the higher potential side of the battery is not higher/lower than earth.

Here is what happens when you touch the "+" side of the battery to ground: enter image description here

Soil resistance might be very low depending on the type of soil. However, air resistance is much higher which will prevent battery discharge.

By the way, both soil and air can conduct current with free ions. (Higher voltages cause big ionization i.e. lightnings) (Pouring salt water in soil also helps lower soil resistance)

Now, if you throw your battery in soil and pour some saltwater in there, you'll definitely be seeing a discharge!

$\endgroup$
0
$\begingroup$

First off, every battery will die eventually, due to self-discharge. So eventually the answer to every one of these is "yes" for that reason.

If you connect only the high potential side of the battery to the ground, it will not noticeably change the process. Unless you have a circuit, current does not flow. There will be some minor current which goes through the air to complete the circuit, but that will be very minor indeed compared to self discharge. You won't notice the effect.

Connecting both sides of the battery can discharge the battery faster. The ground, like all materials, has a resistivity. You will have a circuit and you will deplete the battery. How fast you deplete it depends on a lot of factors, such as the water content of the ground and how far apart the wires are.

Do note that the terms "Earth" and "Ground" are just reference points in electrical engineering. "Earth" typically does in fact mean that you connected the wire to the earth beneath your feet, but that's only a convention. There's nothing magical about the dirt. It behaves like everything else.

$\endgroup$
  • $\begingroup$ Thank you for your response! What is the difference here between the higher potential end of a battery being connected to the ground and it being connected to its negative terminal? What's special about the lower potential of the negative terminal that makes its connection a circuit while a connection to the ground isn't a circuit? $\endgroup$ – bream Dec 16 '16 at 21:26
  • $\begingroup$ If you can draw a loop that current can flow through, then it's a circuit. In the case of a shorted battery, that loop is "positive terminal, through the wire, into the negative terminal, (and through the battery)" If you only have one terminal connected to ground and one terminal not connected to anything, you can't find any circuit (other than "one terminal, into the ground, into the air, to the other terminal," but the resistance of the air is incredibly high, so very little current flows this way... most of the time we'd just say "no current flows" and be done with it.) $\endgroup$ – Cort Ammon Dec 16 '16 at 21:35

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.