Instructables
Portable, Compact and Adjustable ThermoElectric Emergency Generator.


Background:
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).

Concept:
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:
http://en.wikipedia.org/wiki/Thermoelectric_effect

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
Solution:
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.

Result:
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.

Features:
  • 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

Applications:
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

Donations:
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
 
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Step 1: Materials

Picture of Materials
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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

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

Price:
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

Step 2: Construction (Base plate)

Picture of Construction (Base plate)
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Base plate (90x90x6mm):
This will be the "hot side". It will also act as construction base plate to fixate heat sink and some legs.
  1. How you construct this depends on what heat sink you are using and how you want to fixate it.
    I started to drill two 2.5mm holes to match my fixation bar. 68mm between them and the position is matched of where I want to put the heat sink. Holes are then threaded as M3.
     
  2. Drill four 3.3mm holes at the corners (5x5mm from outer edge). Use a M4 tap for threading.
     
  3. Make some nice looking finishing. I used a rough file, a fine file and two types of sand paper to gradually make it shine! You could also polish it but it would be too sensitive to have outside.
     
  4. Screw the M4 bolts through the corner holes and lock it with two nuts and one washer per bolt plus the 1mm washer on the top side. Alternative one nut per bolt is enough as long as the holes are threaded. You can also use the short 20mm bolts, depends on what you will use as heat source.
Next step: Construction of the upper heat sink.


Step 3: Construction (Heat Sink)

Heat sink and fixating construction:
Most important is to fixate the heat sink on top of the base plate but at the same time isolate the heat. You want to keep the heat sink as cooled as possible. The best solution I could came up with was two layers of heat insulated washers. That will block the heat from reaching the heat sink through the fixating bolts. It need to handle about 200-300ºC. I created my own but it would be better with a plastic bush like this. I could not find any with high temperature limit. The heat sink needs to be under high pressure to maximize the heat transfer through the module. Maybe M4 bolts would be better to handle higher force.

How I made the fixation:
  1. Modified (filed) aluminum bar to fit in the heat sink
  2. Drilled two 5mm holes (should not be in contact with bolts in order to isolate heat)
  3. Cut two washers (8x8x2mm) from old food turner (plastic with max temp of 220ºC)
  4. Cut two washers (8x8mmx0.5mm) from hard cardboard
  5. Drilled 3.3mm hole through plastic washers
  6. Drilled 4.5mm hole through cardboard washers
  7. Glued cardboard washers and plastic washers together (concentric holes)
  8. Glued plastic washers on top of aluminum bar (concentric holes)
  9. Put M3 bolts with metal washers through the holes (will later be screwed on top of aluminum plate)
M3 bolts will get very warm but the plastic and cardboard will stop the heat since the metal hole is larger than the bolt. Bolt is NOT in contact with the metal piece.

Base plate will get very hot and also the air above. To block it from heating up the heat sink other than through the TEG module I used a 2mm thick corrugated cardboard. Since the module is 3mm thick it will not be in direct contact with the hot side. I think it will handle the heat. I could not find a better material for now. Ideas appreciated!

Update: It turned out the temperature was too high when using a gas stove. The cardboard become mostly black after some time. I took it away and it seems to work as good as before. Very hard to compare but I have not seen any larger degradation. I´m still looking for a replacement material to test with.

Cut the cardboard with a sharp knife and fine tune with a file:
  1. Cut it 80x80mm and mark up where the module (40x40mm) should be placed.
  2. Cut the 40x40 square hole.
  3. Mark up and cut the two holes for M3 bolts.
  4. Create two slots for TEG-cables if neccessary.
  5. Cut 5x5mm squares at the corners to make place for M4 bolts.
Next Step: Assembly

Step 4: Assembly (Mechanical parts)

Picture of Assembly (Mechanical parts)
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As I mentioned in previous step, the cardboard cannot handle high temperatures. Skip it or find better material. The generator will work without it, but maybe not as good.

Assembly:
  1. Mount TEG-module on heat sink.
  2. Place cardboard on heat sink and TEG-module is now temporally fixated.
  3. The two M3 bolts go through the aluminum bar and then through the cardboard with nuts on top.
  4. Mount heat sink with TEG and cardboard on base plate with two 1mm thick washers in between to separate cardboard from the "hot" base plate.
  5. The assembly order from top is bolt, washer, plastic washer, cardboard washer, aluminum bar, nut, 2mm cardboard, 1mm metal washer and base plate.
  6. Add 4x 1mm washers on the upper side of base plate to isolate cardboard from contact
If you constructed correct: Base plate should not be in direct contact with cardboard. M3 bolts should not be in direct contact with aluminum bar.

Then screw the 40x40mm fan on top of the heat sink with 4x drywall scews. I added some tape also to isolate screws from electronics.

Next step: Electronics

Step 5: Electronics

The main idea was to have a regulated output voltage to charge or power different kind of gadgets. Since the TEG-module produce very low voltage (0-5V depending on heat source) I needed a good voltage step-up and regulator. I wanted to build everything myself and therefore created a whole different project for this since it turned out to be very useful. 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.

You find the step-up project here:
http://www.instructables.com/id/Adjustable-Voltage-Step-up-07-55V-to-27-55V/

I added two more requirements for this project:
  1. TEG-module needs to be protected from overheating
  2. iPhone needs to be protected from to high voltages
Temperature Monitor & Voltage regulator:
TEG-module will break if temperature exceeding 350ºC on hot side or 180ºC on cold side. To warn the user I built an adjustable temperature monitor. It will turn on a red LED if temperature reach a certain limit which you can set as you like.

When using to much heat the voltage will go above 5V and that can damage certain electronics. The step-up can only step up and not step down. I could not find a solution that does both and thereby designed my own adjustable voltage limiter. It combines an operational amplifier and a zener diode to detect a certain voltage and then feed the output signal to a MOSFET transistor. The transistor will shortcut the whole power source but only if higher than voltage limit (5V). That will quickly increase the current and since the TEG-module has a limited output effect it will consequently drop the output voltage. That means it will burn away all energy as heat but at the same time keep a very stable voltage, it simply cannot exceed 5V.  It also turns on a LED so the user can turn down the heat source until the LED goes off again. A simpler solution would be to only use a zener diode to feed output voltage to ground if above 4.7V. But that is not as distinct and probably burn up. I could only find a 5W zener and that is not enough.

The heart of this circuit is a low voltage operational amplifier. I use a MCP6002 which operates at 1.8-6V. It has two units inside which means you can combine both the temperature monitor and voltage limiter with the same circuit.

How to build it is similar to the step-up project, look at that first! Components needed:
  • IC: MCP6002
  • 8PIN socket for IC
  • R3,R4,R5: 1KΩ
  • R6: 22KΩ
  • R7, R8: 470Ω
  • R9: 100KΩ
  • R10: 10KΩ
  • R11: PT1000 temperature sensor
  • R12, R13: 68KΩ
  • R14, R15: 47KΩ
  • P2, P3: 1KΩ (maybe 10KΩ works, not tested)
  • D3, D4: Red LED
  • D5: 4.7V zener diode, low effect
  • T1: High effect MOSFET transistor, BUZ12 or similar
Construction:
  1. Have a look at my circuit layout and try to understand it as good as possible.
  2. Measure the exact value of R3, it is later needed for calibration
  3. Place components on a prototype board according to my pictures.
  4. Make sure all diodes has correct polarization!
  5. Solder and cut all legs
  6. Cut copper lanes on prototype board according to my pictures
  7. Add needed wires and solder them too
  8. Cut prototype board to 43x22mm
Calibration of temperature monitor:
I placed the temperature sensor on the cold side of TEG-module. It has a max temp of 180ºC and I calibrated my monitor to 120ºC to warn me in good time. The platinum PT1000 has a resistance of 1000Ω at zero degrees and increases its resistance along with its temperature. Values can be found HERE. Just multiply with 10.

In order to calculate the calibration values you will need the exact value of R3. Mine was for example 986Ω. According to the table the PT1000 will have a resistance of 1461Ω at 120ºC. R3 and R11 form a voltage divider and the output voltage is calculated according to this:
Vout=(R3*Vin)/(R3+R11)

The easiest way to calibrate this is too feed the circuit with 5V and then measure the voltage on IC PIN3. Then adjust P2 until correct voltage (Vout) is reached. I calculated the voltage as this:
(986*5)/(1461+986)=2.01V

That means I adjust P2 until I have 2.01V on PIN3. When R11 reach 120ºC, the voltage on PIN2 will be lower than PIN3 and that trigger the LED. R6 works as a Schmitt trigger. The value of it determines how "slow" the trigger will be. Without it, the LED would go off at the same value as it goes on. Now it will turn off when the temperature drops about 10%. If you increase the value of R6 you get a "faster" trigger and lower value creates a "slower" trigger.

Calibration of voltage limiter:
That is much easier. Just feed the circuit with the voltage limit you want and turn P3 until the LED goes on. Make sure the current is not too high over T1 or it will burn up! Maybe use another small heat sink. It works the same way as the temperature monitor. When the voltage over zener diode increases above 4.7V it will drop the voltage to PIN6. The voltage to PIN5 will determine when PIN7 is triggered.


USB Connector:
The last thing I added was the USB connector. Many modern smartphones will not charge if it´s not connected to a proper charger. The phone decide that by looking at the two data lines in the USB cable. If the data lines is fed by a 2V source, the phone "thinks" it connected to the computer and start to charge at low power, around 500mA for an iPhone 4s for example. If they are fed by 2.8 resp. 2.0V it will start charging at 1A but that is too much for this circuit. To get 2V I used some resistors to form a voltage divider:
Vout=(R12*Vin)/(R12+R14)=(47*5)/(47+68)=2.04 which is good because I will normally have a bit under 5V.

Look at my circuit layout and pictures how to solder it.

Next step:
Assembly (Electronics)

Step 6: Assembly (Electronics)

The circuit boards will be placed around the motor and above the heat sink. Hopefully they will not get too warm.
  1. Tape the motor to avoid shortcuts and to get better grip
  2. Glue the cards together so that they fit around the motor
  3. Place them around the motor and add two pull springs to hold it together
  4. Glue the USB connector somewhere (I did not find a good place, had to improvise with melted plastic)
  5. Connect all cards together according to my layout
  6. Connect the PT1000 thermal sensor as close as possible to the TEG-module (cold side). I placed it beneath the upper heat sink between the heat sink and cardboard, very close to the module. Make sure it has good contact! I used super glue that can handle 180ºC.
  7. I advise to test all circuits before connected to the TEG-module and start heating it
You are now good to go!

Next Step:
Test and results

Step 7: Tests and Results

It is a bit delicate to get started. One candle for example is not enough to power the fan and soon enough the heat sink will get as warm as the bottom plate. When that happen it will produce nothing. It must be started quickly with for example four candles. Then it produce enough power for the fan to start and can start cool off the heat sink. As long as the fan keeps running it will be enough air flow to get even higher output power, even higher fan RPM and even higher output to USB.

I made the following tests:
  1. Cooling fan lowest speed: 2.7V@80mA => 0.2W
    Cooling fan highest speed: 5.2V@136mA => 0.7W
     
  2. Heat source: 4x tealights
    Usage: Emergency/read lights
    Input power (TEG output): 0.5W
    Output power (excluding cooling fan, 0.2W): 41 white LEDs. 2.7V@35mA => 0.1W
    Efficiency: 0.3/0.5 = 60%
    Comment: Could probably get a little bit more, maybe 0.2W
     
  3. Heat source: 6x tealights
    Usage: Power LED
    Output power (excluding cooling fan @ 30% speed): 0.44W
     
  4. Heat source: gas burner/stove
    Usage: Charge iPhone 4s
    Input power (TEG output): 3.2W
    Output power (excluding cooling fan, 0.7W): 4.5V@400mA => 1.8W
    Efficiency: 2.5/3.2 = 78%
    Temp (approx): 270ºC hot side and 120ºC cold side (150ºC difference)
    Comment: Only run shorter periods
     
  5. Heat source: gas burner/stove
    Usage: Charge iPhone 4s
    Output power (excluding cooling fan @ 75%): 4.25V@300mA => 1.3W
    Comment: This was a long stable test. Charging at 300mA seems to be very stable regarding fan speed and temperatures. I also used the gas stove at very low power. Higher power did not help much, just increasing the temperatures on both sides for little increase in output power.
     
  6. Heat source: Additional heat transfer + alcohol burner
    Usage: Power LED
    Output power (excluding cooling fan): 0.14W
    Comment: The heat transfer is not good enough, TEG voltage too low for charging iPhone.
The efficiency intend the electronics. The real input power is much higher. My gas stove has a maximum power of 3000W but I run it at low power, maybe 1000W. There is a huge amount of waste heat!

Prototype 1:
This is the first prototype. I constructed it at the same time I wrote this instructable and will probably improve it in the future. I have measured 4.8V@500mA (2.4W) output, but could not run at that power for longer periods. The optimum charging speed for iPhone turned out to be 4.25V/300mA = 1.3W. I tested over a long period with stable result. It is a bit tricky though to adjust the electronics for optimal output. If I increase the current over 300mA (at low gas power), then the step-up starts to limit the current (voltage) due to low input voltage from TEG (see graph images of my "voltage step-up" project). When that happen the charging power drastically drops to about 0.2W. I had to adjust the USB voltage/current to be just below that limit, 4.35V without load and 4.25V while iPhone 4s charging. I found out that a fan speed of 60-80% was optimal in this test.

I compared the "gas stove charging" with a "mintyboost charging" using two AA alkaline batteries. Two batteries weight 46g and manage to charge the iPhone from 20% up to 36%. The exactly same charging interval took 60g of gas. The batteries wins this time regarding weight, but as I wrote, this construction can be optimized in many ways! If you also need to carry back the empty batteries, then the gas wins!
  • Current weight of the whole module with all electronics is 400g
  • Outer dimensions are (WxLxH): 90x90x80mm

Conclusion:
I don't think this can replace any other common charging methods regarding efficiency but as an emergency product I think it´s quite good. If I can find a stable way of using this with wood (camp fire), then it would be very useful when hiking in a forest!

Improvement suggestions:
  • Water cooling system (pot)
  • A light weight construction that transfer heat from a fire to the hot side
  • A buzzer(speaker) instead of LED to warn at high temperatures
  • More robust insulator material, instead of cardboard.
Updates:
  • Took away cardboard insulation layer. Could not handle temperatures from gas stove.
  • Experimented with additional heat transfer accessory from a more aggressive fire, see images. It can replace the base plate or be attached to the existing base plate. Tested with alcohol burner but got only 0.14W output. I guess aluminium is not good enough as heat transfer and it probably needs a layer of insulation to not cool before it reaches the base plate. The idea was to put this into a real fire with good ember, might try that also. I want to try with copper but that is expensive and hard to come by.
  • I tested to replace the upper heat sink and fan with a small can of water from this project: LED Power from Fire
    I
     could easily charge the phone with 1W of power and the weight was reduced to only 150g! Water cooling is highly recommended.
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VaibhavR5 days ago

welldone but where can i get the circuit for charging mobile

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....

berkanice5 months ago

Hi, I liked your charger much! Congratulations. I have some questions, I'm glad if you answer :)
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?

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?

Joohansson (author)  berkanice5 months ago
Thank you! Unfortunately I can't help you with that question.
borgassa2ky7 months ago

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?

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 "Oven" or holding container for the coals.

Let me know if you have any ideas or have already tested this theory.

Joohansson (author)  borgassa2ky7 months ago
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!

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.
Kristy luo8 months ago

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.

scottdave8 months ago

Looks like a great project. I may have to try something similar - one day when I have time :) It inspires me though.

good day. i just wanna ask where country did u bought your module? thanks

Joohansson (author)  patricia_philippnes10 months ago
Hi, bought in Sweden.

ok..thanks. is it ok if i replace pt1000 by PT100.. can there be a difference? :)

Joohansson (author)  patricia_philippnes10 months ago

Yes, if you also change R3 to 100ohm instead of 1000.

zubair00110 months ago

Hi, sorry for the late reply. Hope you are good.

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

Test1 chilled water glass.jpgTest2 Table fan.jpg
Joohansson (author)  zubair00110 months ago
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.
zubair00110 months ago

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:

1.) A 12v 0.2A computer fan with heat sink (Hope to run it at lower voltages)

2.) 0.9v to 5 v DC-DC step up regulator (it says 700mA max output current)

http://dx.com/p/usb-dc-0-9-5v-to-dc-5v-voltage-ste...

3.) 2 X TEG modules specified as:

Type number: TEC1-12709
Couples: 127
Umax (V): 15.2V
I max (A): 9A
Tmax (degree Celsius): 67
Dimensions: 40mm x 40mm x 3.5mm
Power cable: 32cm
Max. power consumption: 136.8W

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.

I know 67degC is not much but i hope to cool the other side enough (maybe 30C).

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.

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 :-)

I'm a proper newbie so any help or guidance will be much appreciated. Thanks, Zubair001 :-)

Joohansson (author)  zubair00110 months ago
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.

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.

I hope you solve it, good luck!

Thanks for replying. I think you are right about the fan not starting so i will probably buy this

http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&it...

after I try out the available one when the rest of the parts arrive.

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.

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.

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.???

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.

Thanks!!!.

Joohansson (author)  zubair00110 months ago
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.
http://en.wikipedia.org/wiki/Single-ended_primary-inductor_converter

It would regulate both <5v and >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):
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&hash=item20dd3adf8f

It will regulate 3-15V input To 0.5-30V output. I didn´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. :)
Joohansson (author)  patricia_philippnes11 months ago
Thanks! No, not for sale.
okay..thanks again. :)
Joohansson (author) 1 year ago
If you want a cheap 5W thermoelectric module, back up this project for $19! I ordered one myself =)
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.
Joohansson (author)  thebeave06301 year ago
That might be a good idea to try! Thanks.
Nihal1 year ago
Great project, but reminded me of this: http://www.biolitestove.com/
Granted, it costs an equivalent of 100€ instead of the 80€ 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.
ITS REALLY GOOD SUCCESSFULL PROJECT,
BUT TO BE FRANK I FELT FUNNY BY SEEING YOUR HARD WORK
and so much of money which u spent to produce a small voltage..
there was alot of alternatives for this, i must talk to you, please give me ur mail id
i share my thoughts, even i know a process to charge mobile battery by tree leaves..
Joohansson (author)  graghavendra1 year ago
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!

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.
Joohansson (author)  caleb.gross1 year ago
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
used crome, mozilla, still fail. site has some problem
anyway, posted reply above.. please see it, any info just ask me
best solution for rich people is.. amorphous panels.. buy 20watt panel.
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..
300grams can produce equal energy to charge 3 mobiles at a time.....

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..

3. dynamo. for same struggle u r suffering by this can give 1A charge can be produced for iphone.

4. battery bank, recent days these hitting industry like hell..
10000mah batteries just 30$ (wholesale price) buy few charge it
all can give this suggestion, what is speciality of me? here is my special
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.'

as the present technology which reached buyer, these are the above solution affordable than you machine. :)

all photos are attached here.
amorphous solar panels, PET, cabinet, solar charger bag,
all these are really afforadable compared to any other..
these are reason make you these very high cost
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)
sp-1.jpg1283933691673_hz-cnmyalibaba-web3_49486.jpg575925943_725.jpg562695222_227.jpg454615504_571.jpg519732999_65.jpgIMG_20130502_154902.jpgIMG_20130502_110343.jpgIMG_20130502_154913.jpgsolar panel in hand.JPGSolar-Cell-Charger-Size-in-.jpgSolar-Cell-Charger-Size.jpgSolar-Cell4V-Size.jpgIMG_20130606_113456.jpgIMG_20130606_113446.jpgIMG_20130606_113437.jpg
it was akeshia leaves, they can store electrical charge..
someone charged their battery by those leaves in few secounds..
need more research on this. but i m not sure how to do it
ctien11 year ago
i was thinking of methane microturbine generator for use in country that have no electrical grid. this may work as a power source from using animal/plant waste that produce methane in a large container, the methane comes out and lite as a heat source, on top of the flame there will be your thermoeletric generator. there need to be a big one build as in a big one that can power a small home. its something to think about.
ArsenioDev1 year ago
this is awesome! great job!
Elipsit1 year ago
Hey I really like the idea, well done!
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.
Have you seen these Step Up Boost Modules:
http://dx.com/p/usb-dc-1-5v-to-dc-5v-voltage-step-up-boost-module-green-143571
and
http://dx.com/p/usb-dc-3v-to-5v-voltage-step-up-boost-module-red-146765

They are only $3-4, much cheaper than actually having the boards made haha.

Cheers!
Joohansson (author)  Elipsit1 year ago
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.
very cool, maybe on your next version you could try to use SMD components there not hard to solder as you may think with some good and careful placement and solder paste can be done very easy, i also recommend trying a different fan such as the fans for laptops some of these are 5v and provide high airflow at low power, also a copper heat sink would be better as it has a faster response time to dissipate heat.
Can't wait to see your next version Keep up the good work.
jgeorge141 year ago
I have some issues with your comments. First off, the Battery packs I have are a lot smaller than that contraption you have. Second of all, you should put your phone in airplane mode or shut if off when in the woods due to poor signalling capabilities in those areas usually. The phone searching for signal is the worst battery killer there is. I knwo this from riding motorcycles in the country. We'd keep it in airplane mode, and turn the signal on when we stopped for eating or gas to check up on things back home. Battery would last for 2 days easily doing that. Plus, all it takes is one component on yours to fail and your out completely of the recharge source. With a trusted and proven and tested battery backup, I would bet dollars to donuts that it would be much more reliable, oh, and its not that heavy, less than a pound and it recharges my phone 2 times from dead. I like your idea, dont get me wrong, jsut your example and application are not sufficient. A zombie apocalypse would suit this device just fine though!
First off he uses an iphone they have bad reception compared to other phones anyway so saying that i am sure the user knows about the reception problems and thus would not take a Iphony in bad reception area's, the other point Peltia's are a proven tech just like Solar Panels or Stirling Engines to provide power for different applications where an Grid power maybe a problem, thus this person has provided a tutorial on what is possible more so then, plus another person has told you that most phones now days have other functions such as GPS or maybe used as a map or compass, in this situation cellular towers are not needed.
Battery Packs only last so long especially on a iphone due to the fact of its poor construction and old engineering that Apple constantly uses in there products so next time have a think and maybe some research before ripping on someones instructable.
I have the Asus Padfone 2 16 hour talk time 36 hour talk time when docked in pad mode, why the main proc is 28nm thus saving power while keeping the same speed from the testing i have done this is the fastest phone on the market with long battery and good reception and cost about the same, found by Research...........
Joohansson (author)  jgeorge141 year ago
I agree what you say, but if you use gps tracking the phone is empty in half a day. If you are away for one week, that means 14 recharges and a lot of batteries. If you can power the phone by using only wood, then you only need to bring my 400 grams and a lighter. This is only a prototype, I would not bring this with me as my only hope until it´s robust enough to trust.
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