Portable, Compact and Adjustable ThermoElectric Emergency Generator.

The reason for this project was to solve a problem I have. I sometimes do several days of hiking/backpacking in the wild and I always bring a smartphone with GPS and maybe other electronics. They need electricity and I have used spare batteries and solar chargers to keep them running. The sun in Sweden is not very reliable. When you need it as most it´s either raining or other circumstances that makes it impossible to charge with solar panels. Even when it´s clear weather it simply take too long to charge. Batteries are good but heavy. I have looked for alternatives but they are either very expensive or too large. 

One thing that I always bring with me though on a hiking is fire in some form, usually an alcohol or gas burner. If not that, then at least a fire steel to make my own fire. With that in mind, I got stuck by the idea of producing electricity from heat. I know, the efficiency is very poor but it is at least possible! So, with inspiration from my previous project (Thermoelectric-Fan-Driven-by-a-Candle) I decided to build my own thermoelectric charger. There are similar projects available but not that fulfill my requirements (what I could find).

I´m using a thermoelectic module, also called peltier element, TEC or TEG. You have one hot side and one cold. The temperature difference in the module will start producing electricity. The physical concept when you use it as a generator it's called the Seebeck effect. Thermoelectic modules are mainly used for the opposite effect, the Peltier effect. Then you apply a electric load and it will force a heat transfer from one side to the other. Often used in smaller refrigerators and coolers. Read more about i here:

My requirements:
  • As small, light and portable as possible
  • Robust
  • Adjustable voltage (want to use with broad range of products)
  • At least 5V/0.2A (1W) to charge an iPhone 4s, 2W if possible
  • Compatible with alcohol/gas burner, campfire and candles
With lots of testing and experimenting I come to the conclusion I would need a powerful TEG-module. I have previously used a cheap TEC-module (8€) but it only produce about 0.5W and too low voltage and max temperature. I could use several of them but it will be a more complicated and heat limited construction. I found a 40x40mm TEG that produce 5.9W (4.2V/1.4A) at 180ºC difference. It has a maximum operating temp of 350ºC (180ºC cold side), that should be enough. It´s quite expensive though, about 50€ but that is still cheaper than most solar chargers and much cheaper than other commercial thermoelectric chargers I found.

To transport away all heat and cool it with air you usually need a large heat sink. As my construction need to be compact and light weight, I was thereby limited to very small heat sinks. I then decided to "steel" a small amount of electricity and cool the construction with a motor/fan. That would result in less charging energy but that was the only thing I could think of to keep the size down (and not using water cooling). As it gets warmer, it produce more electricity and also more cooling power from the fan. To block heat from transferring to the cold side I used two heat insulated washers for the fixating and also a layer of insulation between the metal blocks.

First priority was to get a steady 5V source to drive different USB-devices. The module itself produce less than 5V. I solved that by constructing an adjustable regulated voltage Step-up. The detailed specifications can be found later in this project.

When I started this project I had no idea it would actually work. It turned out it even works over my expectations! I can charge my iPhone which was the main goal and it is completely self-cooled even with extreme heat sources.
The cooling is not optimal due to it´s small size, but I´m quite satisfied because I can bring it with me. I would happily see you construct even better solutions, I´m absolutely certain it could be made even cheaper and more efficient. There is a lot waste heat in this construction!

To actually make this yourself, keep reading! More testing and results in the end.

  • Adjustable output voltage
  • Adjustable RPM of cooling fan
  • Adjustable temperature monitor
  • Adjustable voltage limiter
  • Adjustable construction height
  • Optional USB-connector
  • Easy to assemble/disassemble
  • 400g
  • 90x90x80mm

This can be used with a broad range of heat sources and power a broad range of products.
  • Candles (low output power)
  • Spirit burner/stove (hard to control)
  • Gas burner/stove (best so far)
  • Wood stove (not yet tested)
  • Camp fire (not yet tested)
  • Metal can with fire (not yet tested)
  • Barbecue (not yet tested)
  • Light in the dark (LEDs)
  • USB charger (Phones, batteries, etc.)
  • External fan (cooling effect, fire booster, etc.)
  • USB-gadgets (music player, drink cooler, etc.)
  • Charge super capacitor and power high intensity SOS signals

High effect thermoelectric modules are expensive. If you would like to see more of those experiments in the future, please consider a small donation.
Bitcoin address: 1BouwowuprgQrtUYgyzYnNvHyRYbLceqHg

Step 1: Materials

I have not yet fine tuned this construction in the aspect of materials. I simply took what I could come over but hopefully it can be a good inspiration source.

This is what I used.
  • 1x high temperature TEG module: TEP1-1264-1.5
  • 2x voltage step-up (from this project: http://www.instructables.com/id/Adjustable-Voltage-Step-up-07-55V-to-27-55V/)
  • 1x small heat sink. From old PC (BxWxH=60x57x36mm)
  • 1x Aluminum plate: BxWxH=90x90x6mm
  • 1x 5V brushless DC motor with plastic fan (could be hard to find, check this link)
  • Fixation for heat sink: Aluminum bar (6x10x82mm)
  • 2x M3 bolts+2nuts+2x washers for heat sink: 25mm long
  • 2x M3 1mm thick metal washers
  • 4x M4 bolts+8x nuts+4x washers as construction base: 70mm long
  • 4x M4 1mm thick metal washers
  • 4x M4 bolts: 15-20mm long
  • 4x Drywall screw (35mm)
  • 2x heat insulated washers: Constructed from cardboard and old plastic food turner
  • 80x80x2mm corrugated cardboard (Not very good at high temperatures)
  • 2x pull springs: 45mm extended
  • (Optional) Components for a temperature monitor and voltage limiter. Described further on
Pictures showing the three main components: TEG, Base plate and Heat sink

Drill and thread tap for M3 and M4
File and abrasive paper
Loctite power glue (Repair Extreme)

It cost me about 80€ for everything but the most expensive part was the TEG-module (45€).

TEG spec:
I bought the TEP1-1264-1.5 at http://termo-gen.com/
Tested at 230ºC (hot side) and 50ºC (cold side) with:
Uoc: 8.7V
Ri: 3Ω
U (load): 4.2V
I (load): 1.4A
P (match): 5.9W
Heat: 8.8W/cm2
Size: 40x40mm

Next step: Construction of base plate

<p>Hey.I really like your idea.I want to get suggestion from you which TEG module is suitable as I want to generate voltage that is able to charge my Laptop.I am little new to this, but I like this idea very much. So want to make a good portable laptop charger that I can use anywhere easily. But I don&rsquo;t know which components I need that help in making that project.</p>
Can i see a clearer wiring ? <br>Because in wiring the writing of the letter was not read clearly<br>Thanks :)
<p>hey there, nice job. please is there a way i could get the theoretical analysis of the heat transfer between the heat source/sink and the metal plate in contact with it. oluwasubie@gmail.com</p>
<p>Hi,Joohansson,,can you explain me how to measure the output CURRENT of the MAX757 circuit?</p><p>Thanks for your reply in advance</p>
Hey I really like the idea, well done! <br>I recently built a candle powered flashlight last year using a smaller scaled version of what you've done and am planning to try for a bigger setup. <br>Have you seen these Step Up Boost Modules: <br>http://dx.com/p/usb-dc-1-5v-to-dc-5v-voltage-step-up-boost-module-green-143571 <br>and <br>http://dx.com/p/usb-dc-3v-to-5v-voltage-step-up-boost-module-red-146765 <br> <br>They are only $3-4, much cheaper than actually having the boards made haha. <br> <br>Cheers! <br>
A friend and I built this very efficient Thermoelectric Generator for $7.50.<br>It can generate power from a temperature gradient of 5 degrees celsius or greater and can withstand up to 300 degrees celsius before shutting down.<br><br>http://instructables.com/id/Recycled-Energy-ThermoElectric-Generator/<br><br><br> Please vote for our entry in the instructables contests!<br><br>Have a great day!
Cool, that is some kind of joule thief I think, probably very low efficiency. I bought a similar one for just $1 from China but it is not very good.
<p>Hi, I liked your charger much! Congratulations. I have some questions, I'm glad if you answer :)<br>1- I want to charge phones as you do but my idea is to connect 15-20 pieces of TEGs in series. Because I want to use a 35-40 degree celcius heat source and continuous flowing air as cold side (15-20 degrees) Would it be enough for charging phone with USB?</p><p>2- I read that cold side of TEG become hotter due to incapability of cooling side. So the efficiency decreases by time, then, how long charging lasts? </p>
A friend and I built this very efficient Thermoelectric Generator for $7.50.<br>It can generate power from a temperature gradient of 5 degrees celsius or greater and can withstand up to 300 degrees celsius before shutting down.<br><br>http://instructables.com/id/Recycled-Energy-ThermoElectric-Generator/<br><br><br> Please vote for our entry in the instructables contests!<br><br>Have a great day!
Thank you! Unfortunately I can't help you with that question.
<p>hello Sir. You are project is excellent. I am physist teacher on a high school and I try with my students to make this project but we became disappointed. We buy from usa a dc/dc up and down converter x0122 and we pay 30 usd plus 80usd shipping. :(. ... Ok we get up 5.78V but very low current. May we will need a better cooler? You think that we need a better TEC (we have the TEC12706HST)? And after that we will need another circuit to regulate the out voltage not to exceed 5V? What curent we will need to charge a smartphone. Thank you very much for your time. I am waiting forward for your answer. </p>
A friend and I built this very efficient Thermoelectric Generator for $7.50.<br>It can generate power from a temperature gradient of 5 degrees celsius or greater and can withstand up to 300 degrees celsius before shutting down.<br><br>http://instructables.com/id/Recycled-Energy-ThermoElectric-Generator/<br><br><br> Please vote for our entry in the instructables contests!<br><br>Have a great day!
<p>Hello Sir,<br>We, ie my group, decided to implement the same circuit as a hobby project and are facing certain issues.<br>We request you to please give us some pointers as to how to rectify them.<br>The problems faced are - <br>1. The PIN 2 of the IC needs to be connected between R1 and P2. But when we do, we're getting a constant output of 1.76 Volts, irrespective of Pot. Additionally, when we leave PIN 2 NC or we Ground it, the circuit is giving a desirable output, but isn't charging the phone[lack of current?]<br>2. While implementing, we are getting a stable output of 5V when the input is 0.7 - 0.9V. Any Voltage higher than that and our output Voltage is reaching 9-10V.<br>Funnily enough, phone is getting charged at 5V output, but not beyond 6V.<br><br>Thank You, Sir. :)</p>
<p>@joohansson: hi, i really like your project. and if i understand the physics correctly you need to cool down the cold side of the TEC for a rising efficiency.</p><p>you said the gas burner is the best so far. so i can remember when i was using last time a gas burner, the cartridge went very cold. So maybe you can use this effect to cool down the TEC with an use of something like a heating coil around the cartridge. </p><p>i know that this could only work with the gas burner and then wouldnt be anymore universal. but i&acute;m really interested if this would work and how much more efficient it is.</p>
That is an interesting idea because the efficiency of the flame also increases when you heat the gas container. You can try this just by heating it with your hands. If you built it right it would probably work and give more electricity.
<p>can i use this module ???</p><strong><em>TEC1-12715</em></strong>
<p>so your teg moduale puts out 4.2v 1.4 amp at 180 difference do you know how many Volts/amps you were putting out when using candles </p>
I don't think I ever measured that, sorry.
<p>why did you use two voltage step ups when you already achieved 4.2 V around 230 hot side and 50 cold ??</p>
<p>As explained later in the instructions:<br>&quot;The voltage step up is not powerful enough so I built two of them. One will power the 3-5V fan and one will power other electronics.&quot;</p>
<p>Couldn't you just use one ?</p>
<p>welldone but where can i get the circuit for charging mobile</p>
<p>hello sir, i like yr project, your work is fabulous. i am working on this. but there is a problem that i am unable to make the connection between the circuitry and the TEC module, so if it is possible then send me the picture to help me know or guide me that how actually connection is going to make.... thak you....</p>
<p>Quick question, what if you were to construct a miniature oven for a briquette (BBQ coal). Would this produce too much heat? Or would it even be effective if only using 2 or three at a time?</p><p>I am in the process of constructing your design now, and am also trying to design groves on the bottom heat plate that could slide onto a 90X90X90 mm metal &quot;Oven&quot; or holding container for the coals.</p><p>Let me know if you have any ideas or have already tested this theory. </p>
I think it can work. I was going to try that but I'm afraid that the heat will be too hard to control and damage my prototype. It could be that too much heat rises from the oven and make it impossible to cool the upper heat sink. A gas flame is very concentrated if you compare. But if you try it, I would like to see it!<br><br>You can also try to cool with water instead of a fan, that is easier to control and never exceeds 100 C. That would have greater probability of success.
<p>Even i am a seller from China but i didn't know clear how it works. I will learn here, and if you don't mind help me when need, thanks in advanced.</p>
<p>Looks like a great project. I may have to try something similar - one day when I have time :) It inspires me though.</p>
<p>good day. i just wanna ask where country did u bought your module? thanks</p>
Hi, bought in Sweden.
<p>ok..thanks. is it ok if i replace pt1000 by PT100.. can there be a difference? :)</p>
<p>Yes, if you also change R3 to 100ohm instead of 1000.</p>
<p>Hi<strong>, </strong>sorry for the late reply. Hope you are good.</p><p>I got the two thermocouples and the voltage booster delivered only today, so started conducting some crude tests with it. The results are a bit sad actually. I know this is not how its supposed to be done but just was too eager and wanted to see what I could generate with a simple setup. So what the picture shows is two of the previously specified thermocouples connected in series and on a hot plate. and both sides covered with wet tissue and no wind blowing over it. with fan assisted cooling it generated about 0.3v max and stabilized at around 0.25v. So my voltage booster didn't work. I don't know how much more i can i can get it to generate after sandwiching it between aluminium plates and repeating the process. If I consider the above tests valid I would need a total of 8 TECs. I couldn't measure any current when connecting my phone in the circuit which draws 650ma. I probably have to get me some resistor I guess. How do you suppose I can measure the current output ? And can you make any wild guesses on how much current it can give me on a 8 module series setup. Thanks.. :D</p>
I suggest you first learn how the booster works. It probably need a certain voltage just to start up. Maybe you have an adjustable power supply you can experiment with? All TECs works differently, they give a certain voltage and current with a certain load at a certain temp difference. You get maxium effect when your load perfectly maches the specification of your TEC. The phone is also tricky because it needs a certain voltage just to start charging and the current it will draw depends on the input voltage. I think the easiest way to measure current vs. voltage is to attach different resistors (1-100 ohm) to your TEC and measure current and voltage at the same time. Another critical part is your TEC contact surfaces. Whatever you are cooling and heating with it must make perfect contact. I used professional thermal paste, without that it will probably end up damaged, and maybe you have already damaged your modules. I also like trial and error but please read some more about this or you will just be disappointed.
<p>Hi, Joohansson. I am incredibly impressed by your skills and projects. I am not good with electronics but would really like to try this out. But I have a very limited knowledge of electronics and a fairly modest budget. So i am using the following things:</p><p>1.) A 12v 0.2A computer fan with heat sink (Hope to run it at lower voltages)</p><p>2.) 0.9v to 5 v DC-DC step up regulator (it says 700mA max output current)</p><p><a href="http://dx.com/p/usb-dc-0-9-5v-to-dc-5v-voltage-step-up-boost-module-blue-288273" rel="nofollow">http://dx.com/p/usb-dc-0-9-5v-to-dc-5v-voltage-ste...</a> </p><p>3.) 2 X TEG modules specified as: </p><p>Type number: TEC1-12709<br>Couples: 127<br>Umax (V): 15.2V<br>I max (A): 9A<br>Tmax (degree Celsius): 67<br>Dimensions: 40mm x 40mm x 3.5mm<br>Power cable: 32cm<br>Max. power consumption: 136.8W</p><p>I selected the above as I read in a research report that TECs compared to TEGs are more efficient for power generation at lower temps. Also higher the V X I rating of a TEC, the higher you can generate power off of them.</p><p>I know 67degC is not much but i hope to cool the other side enough (maybe 30C).</p><p>I plan to connect them in parallel to increase the amps. Maybe connect one more in parallel. (My sink is rectangular so 3 would fit under it.) I have to arrange a multimeter.</p><p>I need a simple to understand circuit i can make with ready-made parts that will fit together and supply a limited power to the fan and give most of the hard earned amps to my usb charger with some safety so I don't blow up my dear old galaxy S2 :-)</p><p>I'm a proper newbie so any help or guidance will be much appreciated. Thanks, Zubair001 :-)</p>
Thank you! Nice too see you trying this. I'm not an expert either, most of it was trial and error but I was lucky with very few errors. I think you have two problems. A 12V fan running at max 5V might not give you enough air flow too cool it down. It is the starting up that it the most dangerous part because you need much power very fast. If you heat ot up slowly the fan will never start and the module will get same temp on both sides which then give you zero power. The other problem is that 67C is very low indeed. You have a high risk of destroying them.<br><br>I would suggest you to start cooling with water since it much more efficient, to see that everything works as exspected. But even water will reach 67C pretty fast.<br><br>I hope you solve it, good luck!
<p>Thanks for replying. I think you are right about the fan not starting so i will probably buy this </p><p><a href="http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=171077825099&fromMakeTrack=true&ssPageName=VIP:watchlink:top:en" rel="nofollow">http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&amp;it...</a> </p><p>after I try out the available one when the rest of the parts arrive.</p><p>Second I'm still hoping to use just the heat sink to do the job but I may have to use water cooling as a last resort. As far as water exceeding 67C and blowing up the modules, i plan to use the drip and sponge method (I call it that ;-) ). Imagine a soaked tissue spread over the cold side and constantly replenished with drops of water as it evaporates. And if the modules still want to blow, well then I don't have any other use for them. </p><p>Maybe without the use of water, the temperature might not drop too low. But just how low it needs to be to generate enough voltage and current is one thing I will know only after testing it out. For I am going to use not one but two or maybe even four in parallel or series or series-parallel.</p><p>Now if I have a 5v fan, a heat sink, some TEC modules and a 0.9v to 5v DC-DC step up voltage regulator, what else do I need to complete the circuit so that I give only the rated power to the fan and no more (not sure if it'll be good giving it more) and the rest of it to charge the phone.???</p><p>I know you did all your circuits using the very basic components but you know I'm really not gifted in electronics like you :-) and really don't understand much about electronic circuits so I would rather buy complete circuits if they're available rather than do the calibrating, fabricating and soldering things to make more mistakes than maybe I'm already making.</p><p>Thanks!!!.</p>
Ok, that might work. You need to regulate the voltage to not exceed 5v. I could not find a good circuit for it, that was the reason I built it my self. You could technically use just a zener diode (zener diode voltage regulator) but it will flow too much current through it. I used a high effect mosfet transistor to short-circuit voltages over 5v and a simple operational amplifier to control it. I used the zener diode to control the amplifier. But I understand it could be a bit tricky if you have no experience. The solution is not very pretty either as it burns energy instead of use it. The pretty solution would be to use a buck-boost converter or a SEPIC.<br>http://en.wikipedia.org/wiki/Single-ended_primary-inductor_converter<br><br>It would regulate both &lt;5v and &gt;5v. I have not managed to find a really good one but I actually bought this one to experiment with for future projects (search ebay for buck boost if link has expired):<br>http://www.ebay.com/itm/3-15V-To-0-5-30V-Auto-DC-DC-Solar-Converter-Regulator-Boost-Buck-Module-25W-New-/141150576527?pt=LH_DefaultDomain_0&amp;hash=item20dd3adf8f<br><br>It will regulate 3-15V input To 0.5-30V output. I didn&acute;t like it because you needed 3V as minimum but i think that could work for you if you have for example two TEGs in serie.
you've got a nice project.. is your project for sale? please reply soon. thank u. :)
Thanks! No, not for sale.
okay..thanks again. :)
If you want a cheap 5W thermoelectric module, back up this project for $19! I ordered one myself =) <br>http://www.kickstarter.com/projects/david-toledo/the-powerpot-x-most-reliable-10-watt-portable-gene?ref=live
What about the material they use to make the seals around oven doors to use as an insulator between the sides? You might have to cut strips because of the diameter but it can withstand very high temps for long periods. Sorry if that was posted already, I didn't read all the comments.
That might be a good idea to try! Thanks.
Great project, but reminded me of this: http://www.biolitestove.com/ <br>Granted, it costs an equivalent of 100&euro; instead of the 80&euro; you spent, but it incorporates a nice stove as well and provides 2W at 5V. Maybe you could draw some inspiration from it to improve your project. <br>
ITS REALLY GOOD SUCCESSFULL PROJECT, <br>BUT TO BE FRANK I FELT FUNNY BY SEEING YOUR HARD WORK <br>and so much of money which u spent to produce a small voltage.. <br>there was alot of alternatives for this, i must talk to you, please give me ur mail id <br>i share my thoughts, even i know a process to charge mobile battery by tree leaves.. <br>
What can I say, I like to build stuff:) I can admit I did not explore all alternatives before i did this, but I don't regret it at all!<br><br>Please tell me your thought how to charge an iPhone in the wild since that is my main concern. I'll send my mail to you.
Any word on the tree leaves? I'm interested.
No, we only discussed solar panels.
this site gone mad, or my browser gone mad.. i tried alot to reply. but fail to do it <br>used crome, mozilla, still fail. site has some problem <br>anyway, posted reply above.. please see it, any info just ask me <br>best solution for rich people is.. amorphous panels.. buy 20watt panel. <br>coversion is heavy 19%. just half kg, keep inside bag. take it where ever u want. get ur charge, atleast it produce 5W which required to charge in non-summer season also..
1. amorphous solar panels. which are light weight to carry.. <br>300grams can produce equal energy to charge 3 mobiles at a time..... <br> <br>2. flexible solar panel/PET/glass panel (frame less) buy it in large quantity prepare like bag as i made (see pics).. which is really affordable than all these.. <br> <br>3. dynamo. for same struggle u r suffering by this can give 1A charge can be produced for iphone. <br> <br>4. battery bank, recent days these hitting industry like hell.. <br>10000mah batteries just 30$ (wholesale price) buy few charge it <br>all can give this suggestion, what is speciality of me? here is my special <br>buy few anti-radiation stickers (quantum energy sticker/scalar energy) just 1$ each buy 5, patch it front back of batteries, .. batteries can charge 30% faster.' <br> <br>as the present technology which reached buyer, these are the above solution affordable than you machine. :) <br> <br>all photos are attached here. <br>amorphous solar panels, PET, cabinet, solar charger bag, <br>all these are really afforadable compared to any other.. <br>these are reason make you these very high cost <br>1. brand 2. design 3. not required accessories 4. location (if u buy in UK,US,EU always costly these are rich country, so cost also more) <br>

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Bio: I like to design, construct and experiment with both old and new technology, especially when it includes mechatronics. I'm also devoted to photography, computers ... More »
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