DIY battery experiment

I helped my son with his lessons the other day. In chemistry, the topic was electrolysis.

And since my website and YouTube channel are dedicated to various homemade products, it was decided to assemble a homemade DC source.

At the end of the article, you can watch the video version of the experiment (the quality is really “not very good”)

For the experiment I needed:

— kitchen salt

- 9 half-liter jars

- copper cable

- aluminum strips

- Cink Steel

- multimeter and smartphone

In our experiment, 3 metals will participate as electrodes: copper, aluminum, zinc (galvanized steel).

One of the electrodes in each jar will be copper, the second will be either aluminum or zinc.

According to the table "Electrochemical series of metals", the farther the metals of the electrodes are from each other, the greater the voltage will be in one bank.

Salt solution is used as electrolyte. It took 1 kg for 9 cans. salt.

As copper electrodes, I used the cores of the PVA cable 3x2.5. Stranded wire has a significantly larger surface area than solid wire. Therefore ... I “fluffed out” each vein to form such a washcloth:

Copper electrode connected with aluminum. Of course… such contact is short-lived, but I only need it for the duration of the experiment!

As zinc electrodes, a galvanized drywall profile was used.

Inside the jar, the electrodes should not touch. Therefore, I separated the copper washcloth with a plastic spacer cut from a PET bottle.

Where there are aluminum electrodes, I wrapped the aluminum with toilet paper.

There will be no direct contact, and paper will not be an obstacle for the electrolyte!

Poured the prepared brine into jars. The experiment involves 6 cans with electrodes made of copper and aluminum and ...

... and 3 cans with copper and zinc electrodes. Total - 9 cans.

The purpose of the experiment will be to charge the smartphone. To do this, I made an adapter, which you can see here .

So… let's go!!!

We measure the total voltage that formed 9 cans.

As you can see: 5.15 volts.

And now let's see what voltage is in one bank between copper and aluminum.

Result: 0.4 V.

Copper with zinc showed a slightly higher voltage: 0.6V

Some viewers expressed the opinion that this is due to the fact that galvanized electrodes have a large area. I don't agree with this. A large area will affect the amount of current, but not the amount of voltage.

According to the table above, the potential difference between copper and aluminum should be higher, in fact it turns out the other way around. Most likely this is due to the presence of an oxide film formed on the aluminum surface. And what do you think?

Okay, this theory...

Let's see what happened in reality. Surely everyone is interested in what current this assembly can give.

I connect my old smartphone to the adapter and ... About a miracle !!! Charging is on!!!

I leave the circuit alone for half an hour ...

Unfortunately, after half an hour, the charge level, as shown by 1%, remained at the same values. I thought the experiment had failed. But just in case, I put it on charge with a standard power supply - the result is the same. So my homemade battery is not to blame. It's just that this smartphone has a "removed" battery. Unsuccessful specimen for experiments.

Immediately, I connected my working smartphone (which, by the way, was almost empty at that time) and after 1 hour I found that the smartphone was charged by 42%!!! Battery capacity - 2000mAh.

Below is a video version of this experiment: