In this video we'll be making a thermoelectric
generator that can reliably charge your phone using nothing but the heat emitted from candle
flames. The way this works is by using the temperature
difference created between the candles underneath, and the cool water in the tray, to generate
electricity. At first this might seem a bit of a novelty
at first, but it could be genuinely useful in some very real situations. For example, if you are out camping and your
phone runs out of juice, you could use the thermal generator to charge it back up over
a camp fire.
A little closer to home it could come in handy
if there's ever a power outage, and you could make some hot chocolate whilst you're at it. However you choose to use it, this is a very
fun project and it doesn't take much time to build, so let's get to it. By the way, if you like the quality look of
the charging cables used throughout this video, stick around for your chance to win them,
courtesy of the manufacturer Native Union. So, the first items we'll need for this project
are 10 thermoelectric plates. These are usually used in devices like portable
drinks coolers, and they work by essentially moving heat from one side of the plate to
the other when electricity is applied. This means that when the hot side is kept
cool with a heatsink, the temperature of the cold side, from which the heat is being removed,
can drop low enough to freeze water.
Most interestingly, these plates can also
be used to generate electricity by heating up one side and cooling down the other. This is called the Seebeck effect, and is
what we're going to be taking advantage of in this project. They're surprisingly cheap as well, so I've
placed international purchasing links in the description. Next thing we'll need is a metal tray to hold
the water – in my case I used a bread tin. When you choose yours, you'll need to make
sure that the base is large enough to accommodate all ten plates, which need to be stuck to
the bottom of the tray with the printed text facing upwards.
We need to use thermally conductive glue for
this, and we need to use enough of it so that the glue spreads to the edges when the plates
are squashed down. Again, you can find links to this glue in
the description. Now, you'll notice that the red and black
wires form pairs – these need to be soldered together, though if you don't have a soldering
iron you could probably get away with twisting them together if you leave yourself some extra
length before trimming the wires down. 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've 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. So what we'll need is the aforementioned voltage
regulator, which takes this higher voltage and stabilises it at 5v – it even has a standard
USB socket so that we plug devices straight in with no messing around. Like the rest of the parts required for this
build, you can find purchasing links to it in the description. To keep it out of the way, we'll be mounting
it over the tray using a strip of aluminium.
I trimmed mine down from a larger piece by
first scoring it with a knife, and then bending it repeatedly until it split. I then used some pliers to bend over the edges
so that it hooks tightly over the rim like so. Now we can insert the wires into the voltage
regulator's input, and clamp them in place. Because of the way we've stuck on the pads,
the polarity of them is inverted, so in this case red is negative, and black is positive. It is always worth confirming this with a
multimeter before use however. When we glue it to the aluminium, we can stick
a piece of cork in between to act as an insulator.
The regulator can then be glued down on top. Our generator is now almost complete, but
before we try it out we need to make a little lip to help catch more heat. To do this, we can get another piece of aluminium
that's large enough to cover the plates with some room to spare. We can then score some lines about a centimetre
in from the outer edges, and bend them slightly downwards to make a lip. Looks pretty snazzy – especially with the
rounded edges, which were made simply with a file.
This can then be glued to the plates using
some more thermally conductive glue. After you've 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. After it's set the generator should be looking
something like this, and the only thing left to do is make the stand. To make it we can again use some aluminium,
and bend it into shape. You can customise its dimensions to fit the
tray that you use, but 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. Although it's quite a simple stand, it's surprisingly
quite rigid. Now it's ready to try out! So 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. As the power increases, the voltage display
should light up too, and it should continue to rise as the temperature difference increases. Once over 10v, 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. If you were to use something like snow or
ice instead, it would not only last longer, but would initially generate significantly
more power, so that's something to keep in mind for the winter months.
So, that's it for this project, but what about
that cable giveaway I mentioned earlier? Well, there are four cables you can win, all
made by Native Union, who specialise in quality above all else. They're really nicely made, so are probably
the only cables you'll ever own that are actually good to look at by themselves. They have some nifty functionality too. The casing of the Jump cable, for example,
actually works as a charging buffer, so can give you an extra 20% boost in battery power
when you don't have access to electricity.
Alternatively, the Key cable doubles up as
a key chain, so you'll always have it with you when you're out and about. So, to be in with a chance of winning all
four of these cables, simply sign up to Native Union's newsletter with the link in the description. Good luck! So, I hope you've enjoyed this video. If you did, don't forget to hit that like
button, and maybe consider subscribing if you haven't already. I'm Matt, and I'll see you next time..