[Gilles Messier] at the Our Own Devices YouTube channel recently took a look at an interesting device — an electric lantern powered by a candle. At first glance, this sounds completely absurd. Why use a candle to power LEDs when you can use the light from the candle itself? This gadget has a trick up its sleeve, though. It lets candle light out and uses the heat from the candle flame to generate power for the LEDs.
The small Peltier “solid-state heat pump” module in the lantern acts as a thermoelectric generator, converting heat from the candle into electricity for the LEDs. The genius of the device is how it handles the candle “exhaust”. A bimetallic disk in the chimney of the lantern closes when the air inside the device is hot. The Peltier device converts the heat differential to electricity, causing the air inside the lantern to cool. Meanwhile, the candle is beginning to starve for oxygen. Once the air cools down a bit, the disk bends, allowing stale smoke out, and fresh air in, allowing the candle to burn brightly again. Then the cycle repeats.
[Gilles] does a deep dive into the efficiency of the lantern, which is worth the price of admission alone. These lanterns are pretty expensive — but Peltier modules are well-known by hackers. We’re sure it won’t be too hard to knock together a cheap version at home.
https://www.elektormagazine.com/labs/peltier-lamp
Sounds like you’re unhappy here. Perhaps you should ask for a refund, and go to some other website where miserable jerks like you are happier.
It’s comments like this that I vowed I’d never contribute any article or project ideas to Hackaday. This lantern is a real product that has positive reviews (go look it up before you make snide remarks).
Well… never mind. The comment I was responding to was taken down. My comment still is valid though. There are way too many naysayers and arrogant commentators roaming this site.
The way we see the world creates the world we see ;)
There are too many naysayers and arrogant commentators on the Internet.
On Hackaday, however, you can report negative / insulting comments using the “Report comment” button, and if a few people do the same, the crappy comments automatically disappear and go back into our moderation queue.
If you see a comment that violates our “be nice” policy, please _do_ help us by reporting it!
(Full policy below.)
Well I guess it had a negative review too (until HaD deleted it lol)
I saw this when it came out several years ago, and went through the arithmetic: I can buy disposable AA cells to power the same amount of LEDs, and still come out ahead in weight and cost. With rechargable lithiums, it’s just a no-brainer. I can carry more lumen-hours in rechargeable batteries than I can carry in tea lights.
You have a point, but think of this scenario:
store both in a closet for ten years and see which solution still works, your high power rechargeable batteries or the one based on fire…
Fun little device, cool to see it here on hackaday
You can also I expect replace that tea light candle with almost anything else that burns relatively easily. So should you ever be without candle but have some oil and anything that can act as wick (though some oils and alcohols won’t want/need a wick anyway). I wonder how bad the soot build up is and if that flap actually extends the burn time.
As a light source that is functional, reliable and practical for all occasions I’d not rate this particular implementation all that highly, but it certainly is interesting, looks good and works. It is the sort of thing I could see having for your off grid cabin/caravan quite happily – you might not expect to use it all that much, but when you need a light and your usual generator is dead this is a good compact and attractive backup, along perhaps with one of those gear wind up or shake powered torches.
When I stop by garage sales, I check the “Free” boxes for half used candles. I have a couple of boxes now in my garage.
A slightly larger one, possibly even with a USB charging output option (even if it’s just a slow charge) actually sounds moderately useful and cute. The heat that’s lost isn’t actually wasted anyway if you’re off-grid when it’s not warm.
I will say that his efficiency numbers are probably way, way high: I highly doubt that thing’s capturing more than a few watts of heat – maybe even less. There’s no reason you can’t scale up the number of thermopiles though: the whole thing’s getting hot, after all.
Biolite makes a USB charging version camp stove. Fuel it with twigs and charge your cell phone (slowly). https://www.bioliteenergy.com/
Because it is thermoelectric generator that uses Seebeck effect?
The Wordbook encyclopedias I grew up with had plans for a candle powered radio (1 vacuum tube), no Peltier module in sight! Twisted dissimilar wires soldered with one end near the candle flame (thermocouples) provided the power.
Would this be better than a crystal radio?
I recall seeing it in Encyclopedia Britannica.
It was a few hundred copper-iron pairs in series, 4-5 inches long, arranged in a flat sunburst. The hot ends in the middle were heated by plopping it on top of a camp lantern, with the cold ends splayed in the foot-or-so outside diameter.
I built one based on the encyclopedia article, sometime in the late 70s.
It didn’t provide enough power for a tube radio, but was ample for a transistor radio. 2-3 volts at dozens of mA.
Going through the design optimization years later I realized it could be improved a great deal by using small (30 ga) copper wire and large (20 ga or so) iron wire. The copper has good electrical conductivity but too much thermal conductivity: with equal thickness wire, the iron dropped too much voltage, and the copper heated the cold ends too much. Making the copper much thinner than the iron minimized the overall losses.
I didn’t have the resources to build one (po’ boy), I’m glad you did!
Different world book mid to late 60’s but it was a hookah powered radio where everyone has headphones and hoses. They were all tuned in to the BBC somewhere in India.
https://www.kickstarter.com/projects/tpod1/tpod1-thermoelectric-power-on-demand
got one thru kickstarter. Works very nice and is quite bright.
I like it…
Discontinued unfortunately…
I’m not sure the host understood the function of the bimetallic flap. He claims its movement regulates the “flow of air” through the lantern and that it is nominally open, but closes when heated by the candle. Furthermore he implies that the function of this is to control the amount of available oxygen in the lamp, so as to throttle the candle flame.
However, at 9:12, the lantern cold and it appears to me that the bimetallic disk is closed. I don’t think the disk acts as a damper to throttle the candle at all. Rather I think it acts as damper to control the peltier hot-side temperature by regulation how much heat is trapped at the top of the flame column. Thus, you WANT it to be closed while cold. Then, as heat builds up (and if it becomes excessive) the disk can open allowing trapped heated air to escape.
It appears to me to be open when cold. At 9:12, I see the disc having a bowl shape with a gap between the rim and the top surface of the fire box.
Are you seeing it differently?
I am shocked I tell you – 22 comments and not a single person has said they should have used a 555 timer – shocked I say
Actually in many of the articles the comments have as much information as the original articles . Keep adding the extra information
That’s because it goes without saying, it’s like green sand being good for all occasions
“shoulda used a 555” is for projects that use a microprocessor / fpga, which this one didn’t
This may not may not be useful in your home, but it seems perfect for tables in a restaurant with dimmed lighting. You have the ambience of candle light plus extra light from the LED top for reading the menu, without needing batteries or a power cord.
candle gives up more than 99% of it’s energy as heat…
even if your teg/light system only got a 5% efficiency, you’re already dealing with an order of magnitude of light more…. and convenient, placeable as you want, directional if you prefer…
I have a commercial version from some years ago (“Luminiser” – still made and sold, though they’ve apparently gone to an oil-lamp system) and…it’s actually kind of neat in a power outage or nice evening on the patio. As others have said the flame has an excess of heat energy so even a poor conversion of that adds a good deal of illumination. Lots of fun to light the candle and as things warm up the secondary lighting takes over in a nice way. I’ve made a few versions previously using cooling modules and LEDs but this one has a place of honor just because it isn’t a rats nest of wires :-)
Look like a old news to me. http://www.douglas-self.com/MUSEUM/POWER/thermoelectric/thermoelectric.htm
I have this exact model, and yes it works very well.
I only get it out during winter though, and I have it lighting up the wall beside my TV.
From memory I think it was made in Canada.