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In the spirit of Halloween, I thought I would expand on the idea of fruit and vegetable batteries and make a battery out of pumpkins! This is a very quick and easy Instructable, so let's get started.

Step 1: Materials

Note: This can be done with just one pumpkin. The more pumpkins you use though, the more power you get! That being said, I used two pumpkins connected in series to get more voltage.

Here is a list of everything you will need to make this battery.

  • Pumpkins
  • Galvanized screws or nails
    • Galvanized just means it has been coated with zinc, any thing zinc-coated should work.
  • Something copper, like nails or segments of wire
  • Wires

I got two galvanized screws and 2 pieces of a thick copper wire at the hardware store for less than a dollar. Any other zinc and copper items should work.

If you have alligator clips, that will make connecting everything together easier. These can be purchased in packages of 4-6 for a few dollars.

Step 2: Place the Galvanized Material

Put one galvanized screw (or whatever other item you are using) in each pumpkin. Leave a little bit of the screws sticking out to connect to the wires later on.

Step 3: Place the Copper

Put a piece of your copper material in each pumpkin as well. Place the copper near the galvanized material but make sure they are not touching inside or outside of the pumpkin.

Step 4: Connect the Pumpkins

Connect the galvanized material in one of the pumpkins with the copper material of the other pumpkin using one of your wires. This will connect the pumpkins in series which will yield a higher voltage at the end result.

Step 5: Connect Power Wires to the Pumpkins

  1. Connect a wire to the unconnected piece of copper on one of the pumpkins. I used a red wire because there will be a positive voltage at this part of the battery. (See the pumpkin on the right.)
  2. Also connect a wire to the unconnected galvanized material of the other pumpkin. I used a black wire because this is the negative terminal. (See the pumpkin on the left.)

Note: You may have noticed I have different screws. I just wanted to try a different type of screw to test it out. I got the same results with both of the different kinds of screws.

Step 6: Pumpkin Power!

Now there is a voltage between the other ends of the red and black wires we just connected. I connected these to a digital multimeter and measured 1.613V. Not bad for some pumpkins!

You may get a different voltage depending on the exact zinc/copper items you use and your pumpkins. Note: For my design that I just demonstrated I have two pumpkins connected in series. This increases the overall voltage that I am getting. Each of the pumpkins I used provided about 0.8V. Putting the pumpkins in series combined to give me the 1.6V. Adding more pumpkins in series would increase the voltage even further. If you want to increase current, connect additional pumpkins in parallel.

Thanks for reading my Instructable, and don't hesitate to ask if you have any questions!

<p>thanks for the idea....I would like to try to light an LED bulb but finding I don't have enough AMPs. Any thoughts on how to achieve this?</p>
<p>Hello. There are several comments below that discuss ways to get more power out of this system. Check those out.</p>
<p>This is very interesting sir!</p><p>If I had pumpkins growing instead of watermelons I would definitely do this!</p>
<p>Actually, watermelons might work too! I have seen this work with potatoes and apples before, so I think just about any fruit or vegetable will produce at least some voltage.</p>
<p>Man I want some spaghetti squash with some sauce on top.</p>
<p>XD</p>
I am trying this for my technology project do u think it is a good idea??<br><br>
<p>try boiling the pumpkin and then mashing it between zinc and copper plates in a series. works for potato by rupturing the cells and allowing electrolytes to flow more freely, thereby lowering the vegetable's internal resistance. </p>
<p>How much current do you get from this?<br>Will it run a joule thief?</p>
<p>The current is dependent on ohms law, Voltage = current*resistance<br>or Current = Voltage / resistance in this case. Increasing the surface area of<br>the Cathode and anode will indeed aid in the reaction processes and thus<br>increase the induced voltage, though possible only slightly. You should<br>consider using different Cathodes and anodes that might be more receptive to<br>Electron transfer. Increasing the size of the pumpkin would really only help<br>limit the Acids from becoming too diluted with ions and slowing the reaction.<br>This wouldn&rsquo;t likely be an issue unless you were using a very small pumpkin. To<br>lengthen the life of your pumpkin battery, you would want to keep your pumpkin fresh and use a larger ratio of Cathode/anode material to a smaller surface area. To increase the voltage you could also try using a different Fruit with Stronger acids. From my understanding Lemons are an excellent source of power for these kind of things. </p>
<p>Getting a substantial amount of current from this is tricky. With just the two pumpkins in series, I was not getting enough current to actually be able to measure it with my multimeter. This issue is related to the chemical reaction that takes place within the pumpkins that generates the electrical energy. (I could explain this in greater detail if you would like.) As I mentioned in my last step though, you can get more current by connecting more pumpkins in parallel. For something small with low power demands, like a joule thief, I think several pumpkins in parallel should do the trick. I have not tried this myself though.</p>
<p>What if, instead of more pumpkins, just use more zinc/copper combinations of nails in the same pumpkin? Maybe on the opposite side. </p>
<p>That should work as well. I'm not any type of chemistry expert, but I believe the rate of the chemical reaction would increase if the surface area of the components involved in the reaction increased. For example, using a bigger galvanized screw (or other zinc item) would provide more zinc to react with the pumpkin and ideally increase the voltage and current available.</p>
<p>I agree, that was my basic reasoning behind it too. I doubt that the small nails will be able to drain the energy from the entire pumpkin. More likely just the localized area they are stuck to. Moving them might refresh the effect, and adding more to the same pumpkin might too. It's worth a shot I'd say.</p>
You can also increase the current by increasing the electrode surface area, just by using multiple nails or wires connected together. You can also order rectangular copper and zinc electrodes online from science supply stores, but that is more expensive than scavenging for materials.
What is in the vegetables that fuels the power? Would this not work with any liquid such as water?
<p>Point #1) pumpkins are actually a Fruit. Point #2) all Fruits have acids filled Electrolytes. Electrolytes allow electrons to flow from on point to another, like ions do in water. Note* deionized water will not conduct electricity. Its because of this exchange that a complete circuit can be made from the - Anode(copper) to the + Cathode (Zinc); or galvanized nail this case, inside the fruit. this can be done with any variety of Fruit. Typically the stronger the acids the higher the voltage out put possible.</p>
<p>I don't know of the exact chemical (I think it is some sort of acid). But this 'chemical' inside the pumpkins reacts with the zinc on the galvanized screw. This chemical reaction frees up electrons which is where we get the electricity from. This would not work in just water, but I have seen salt water solutions work in a similar way (since salt has electrolytes).</p>
Plug it into the ocean then see what happens! Would be interesting if you could find out..
<p>Great idea, thanks for sharing ..</p>
I've seen something like this using banana &amp; lemon combine.Thanks for sharing!
Interesting experiment, I will have to tell my neighbor about this. They raised a mess of pumpkins this year!<br>Actually, I never thought about pumpkin batteries before this instructable. I will experiment on tomatoes.
clever

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