In this article, we will be making a thermoelectric generator that can reliably charge your phone using only the heat generated by the candle flame. It works by using the temperature difference between the candles underneath and the cool water in the tray to generate electricity.
It may seem unnecessary at first, but it can be really helpful in some very real situations. For example, if you are camping and your phone runs out of power, you can use a thermal generator built on Peltier elements to charge it over a campfire.
Details and parts:
- Thermoelectric, Peltier Cooling Modules TEC1-12706 – 10 pieces – https://s.click.aliexpress.com/e/_DlWVYZB;
- Metal water tray or bread tin;
- Thermal conductive glue – https://s.click.aliexpress.com/e/_DC9jkIh;
- Voltage regulator, DC-DC step-down module – https://s.click.aliexpress.com/e/_DeWtFzb;
- A strip of aluminum;
How to make a thermoelectric generator with your own hands, instructions:
So, the first items we will need for this project are 10 thermoelectric plates. These are usually used in devices such as portable drink coolers, and they work by essentially moving heat from one side of the plate to the other when electricity is applied.
The most interesting thing is that these plates can also be used to generate electricity by heating one side and cooling the other. This is called the Seebeck effect and is what we are going to be taking advantage of in this project.
The next thing we need is a metal water tray – in my case, I used a bread tin. When you choose yours, you need to make sure that the base is big enough to hold all ten plates, which you need to glue to the bottom of the tray with the printed text facing up. We need to use thermal conductive glue for this.
When you reach one end, you can simply continue the circuit by bridging it over to the other plate like so. The wires at the opposite end can just be left loose, as they will be later connected to a voltage regulator.
To stop our joints from touching the tin and shorting out, we can stick a strip of electrical tape to protect it from short circuits.
Now, as we have connected all of our thermoelectric pads in series, the voltage could potentially be as high as 15v, which is too high for phones, which only need 5v.
Therefore, what we will need is the aforementioned voltage regulator, which takes this higher voltage and stabilizes it at 5v – it even has a standard USB socket so that we plug devices straight in with no messing around.
To keep it out of the way, we will be mounting it over the tray using a strip of aluminum.
Now we can insert the wires into the input of the voltage regulator and clamp them in place. Because of the way we have stuck on the pads, the polarity of them is inverted, so in this case, red is negative, and black is positive. You can also check it with a multimeter.
The regulator may then be glued on top through insulating thick tape.
Our heat generator is almost complete, but before we try it, we need to make a little lip to trap more heat. To do this, we can get another piece of aluminum that is large enough to cover the plates with some room to spare.
We can then score some lines about a centimeter in from the outer edges, and bend them slightly downwards to make a lip. The rounded edges were simply made with a file.
Then we glue it to the plates with thermally conductive glue. After you have done this, I recommend that you clamp it all together so that it makes a tight thermal bond, leaving it for about 12 hours whilst the glue dries.
Once installed, the thermoelectric generator should look something like this, and all that is left is to make a stand. To make it we can again use some aluminum, and bend it into shape.
You can customize its dimensions to fit the tray that you use, but for height wise, you need to get the tray fairly close to the candle flames without them actually making contact, as that would cause things to get sooty.
Now it’s ready to try out! Therefore, we can get as many candles as will fit inside our base, carefully light them all, and then place the generator on top. Now we can pour some cold water into the tray and wait for the generator to kick in. In a few seconds, the little LED on the regulator should start to glow.
Once over 10 volts, we can plug in the device we want to charge, and press the regulator’s power button to activate it. The device should now start charging! It’s not quite as quick as a fast charger, as it only delivers about one and a half watts, but that’s not too bad at all considering that it’s being generated by the heat from the candles.
To keep the temperature difference high, the water does need to be refreshed when it gets warm, which needs to be done every 10 minutes or so. It is better to use snow or ice for longer power generation, winter time is better for this.
Watch a video demonstration of our homemade thermoelectric generator and how it was made: