Introduction: Thermoelectric USB Charger - Off Grid Electricity.

Picture of Thermoelectric USB Charger - Off Grid Electricity.
This strange looking pan is a device to generate power from a low temperature heat source. By using the seebeck effect, it is able to produce enough electricity to charge a cell phone and other USB devices. The best part about this contraption is that it has no moving parts.

The device has a nimh power pack which stores electrical energy for use whenever you need it, the power pack can be detached for use anywhere. The output is 5V through a USB port. This device would work especially well were there is snow available for extra cooling – for example off grid cabins in remote (snowy) locations. It could serve as dual purpose - melting snow for water and producing electricity ? The bigger the temperature difference between the two sides of the peltier the greater the power output.

This idea is not new, it has been around for a long time. See here for some very
old thermoelectric generators

The peltiers produce 0.6W of power to recharge the battery pack.

If you like this, please vote for me in the Off Grid challenge. Click here to view the contest.

Here's what you'll need :

Video  guide to making the pan :


Step 1: Tools and Materials

What you'll need :

  • 2 x TEC-12706 Peltier Modules
  • DC-DC USB Step Up converter
  • Small switch
  • Project box
  • Small scrap of vero board
  • 4 x 3000mah nimh/ni-cd batteries
  • 1N4001 diode.
  • Battery holders for the batteries
  • Miscellaneous wire, solder etc.
  • Thermal compound
  • Aluminium or copper milk pan
  • PC CPU Heatsink
  • 4 M4 x 12 bolts
  • 4 Long (>75 mm) M6 bolts for the feet
  • Electrical connectors (screw terminal type)
  • Silicone tubing.

  • Drill & drill bits
  • Multimeter
  • M4 Tap
  • Soldering iron
  • Files
  • Screwdrivers
  • Spanners to suit the bolts

Notes: The PC heat-sink must be big enough for the two peltiers to sit on.
I bought the DC-DC converter on ebay, it has an integral USB port.

Step 2: Mark Out Holes in the Pan for the Heat-sink Bolts

Picture of Mark Out Holes in the Pan for the Heat-sink Bolts

The heat-sink will be bolted to the milk pan. Mark 4 holes to for bolts to go through the milk pan into the heat sink. The sizing of these holes will depend entirely on the heat-sink

Step 3: Drill Holes in the Pan to Attach the Heat-sink

Picture of Drill Holes in the Pan to Attach the Heat-sink

Drill out the holes you marked. The drill size should be 4mm

Step 4: Drill and Tap Holes in the Heat-sink for the M4 Bolts

Picture of Drill and Tap Holes in the Heat-sink for the M4 Bolts

Drill matching holes in the heat-sink with a 3.2mm and cut an M4 thread in these holes.

Step 5: Lay Out the Peltiers

Picture of Lay Out the Peltiers

Lay the peltiers onto the heat-sink, ready for the dry fit. It's best to do a dry fit first to make sure that everything lines up properly. When you're ready to assemble the pan for good, apply thermal compound to both sides of the peltiers.

Step 6: Bolt It Together

Picture of Bolt It Together

Bolt the pan to the heat-sink using the M4 bolts. Make sure the peltiers are sandwiched neatly in between.

Take care not to overtighten the bolts as this could crush the peltier chips.

Step 7: Slip Some Silicone Tubing Over the Wires

Picture of Slip Some Silicone Tubing Over the Wires

Slip some silicone tubing over the electrical wires to help protect them from the heat. This also makes the wires a bit neater.

Step 8: Add Legs

Picture of Add Legs

Drill four 6mm holes around the edge of the pan for the feet (bolts).

Step 9: Attach the Legs

Picture of Attach the Legs

Bolt the four legs onto the pan.

Step 10: Attach the Screw Terminal Blocks

Picture of Attach the Screw Terminal Blocks

Bolt the screw terminal to the side of the pan using two M3 x 20mm bolts.

Step 11: Connect It All Up and Test

Picture of Connect It All Up and Test

Connect the two peltier chips in series using the screw terminals. Light some candles underneath the thermoelectric pan and fill the pan with water.

Connect a multimeter to the output and measure the voltage. If the voltage is very low, such as 0.1 – 0.5 volts, then one of the peltiers is probably connected the wrong way around. Flip the wires around on one of the peltiers.

It will take around 5 minutes for the heat-sink to reach full temperature, at this point you should see between 3 – 7 Volts DC output.

Step 12: Build the Step Up Circuit

Picture of Build the Step Up Circuit

Solder up the circuit for the step up converter. The peltiers are connected to the battery pack through the 1N4001 diode. The step up converter is connected to the battery pack through the switch.

Note: The 3.5mm jack shown was not used in the final build.

Step 13: Fit It All Into the Project Box

Picture of Fit It All Into the Project Box

Cut out the holes in the project box for the switches and USB port. The USB board is glued to the scrap of strip-board to keep it securely in place and the strip-board fits into the slots in the project box.


Cambenora (author)2012-09-06

Excellent instructable. It's good to see Peltier cells being used in this way.

scraptopower (author)Cambenora2012-09-06


mnaderi11 (author)2017-03-21

Thank you @scraptopower ;)
It was much helpful to get making.

Nivedha Anjaneyan (author)2016-07-10

what will happen if we use a larger heat sink? and not a a compact one

masterleo (author)2015-02-06

could you please tell us how many Amps (and watts ) it produces ? ?

please add it in the instructables

blamo89 (author)2014-08-12

Check out the biolite camp stove its similar but you can also cook on it

HarshB (author)2013-12-02

This is a excellent instructable! I was wondering however, do we need to use 2 heatsinks; one in the bottom of the pot, and one in the inside? Or just one in the bottom. Appreciate the help.

haniffwahab (author)2013-03-27

i want to ask, i have try the project, but my thermogenerator have produce only 0.5v , could u give some advice how to make thermogenerator produce 3v and how about temperature and temperature ambiance?

haniffwahab (author)2013-03-27

i want to ask, i have try the project, but my thermogenerator have produce only 0.5v , could u give some advice how to make thermogenerator produce 3v and how about temperature and temperature ambiance?

mlove8 (author)2013-01-29


keegancdr (author)2012-10-18

this doesnt charge an iphone.... :( what a waste of money ...

vibrion (author)keegancdr2013-01-11

check this:

keegancdr (author)vibrion2013-01-11

I used a different step up converter and it works just fine

scraptopower (author)keegancdr2012-10-19

Apple like to annoy everyone by making things that only work with apple. There is a way to make it charge, by adding some resistors somewhere. Have a look on Google for apple usb charger schematic or something similar.

DevonJM (author)2012-12-05

There is one severely flawed aspect to this design you have shown, you NEVER put your screw points at a diagonal to your tec components, so never at the corners, only along the sides or else the compression will interfere and break the modules in far shorter time span than they are spec'd for. Change that, and its perfect.

poofrabbit (author)2012-11-27

Hey congratulations on being a finalist in the hack it contest! Good luck to you!

keegancdr (author)2012-10-11

i got all my parts in today! i am confused as to where to soldier in the diode. could you show me a picture of the whole wiring layed out without the 3.5mm jack in there? i just need to see a picture . thanks alot! :)

TurboFusion (author)2012-09-29

I have a question, If you used a more powerful peltier element for the thermoelectric charger, would you get a larger power output? If it would, then would it be more efficient to use more small peltier elements, or to use one big peltier element?

keegancdr (author)2012-09-10

is this the step up dc-dc converter you used?

scraptopower (author)keegancdr2012-09-10

Yep, that's the one.

keegancdr (author)scraptopower2012-09-10

Thanks a lot! Another question if I were camping could I leave this contraption running all night? Or untill the candles went out? Or is there a time limit to how long I can run it? I'm wondering for like leaving my phone plugged in and charging over night ( in a fire safe environment )

Lemon (author)keegancdr2012-09-27

If you were worried about the candles being left overnight, you could try boiling up some water and replacing the candle with this heated water. Cooling 3 pints of water from 100 degrees to 15 degrees involves roughly the same amount of energy transfer as burning one of those candles would, so if you had a big enough campfire to boil a large amount of water during the day it could be something to consider.

rrepass jr. (author)2012-09-09

So, (1)how hot does the thing need to get? Would it work well on top of say, a wood stove, if left or (2) does the water "have" to stay cool?

nice guide, cheers!

scraptopower (author)rrepass jr.2012-09-09

It needs a temp difference of around 80 - 120 centigrade to charge. The water doesn't have to stay cool. It seems to hold steady at around 40c after a few hours running so not really cool. But the cooler you can keep the top the better. A little tower with cloths resting part way in the water would probably help cool it by evaporation.

I think it would work quite well on top of a woodstove, though it might possibly be too hot.

odiekokee (author)scraptopower2012-09-10

they make fans for woodstoves with a copper base and heat transfer bar, then the fan motor and cool side radiating fins up top, used to spread the heat of a woodstove around a cabin or other similar thing. Ecofan is oen of them.....expensive of course, as is the biolite thing.

I have seen stirling motors with fans that do the same, without electricity. Make one!!

Yeah, stringstretcher, I was thinking the same, but have you seen any designs here... def want to not buy, but build ;)

Stirling build designs are all over the internet. I have made some using plans like this. They ran off of a stove quite well, but when I place one on the grill the solder joints melted! Lots of fun to build, and if you find a use for one, even better!

Gadget93 (author)2012-09-10

This would be great to use inside my Infinite Improbability Drive. I use a nice hot cup of tea to power it though.

Zombie_BBQ (author)Gadget932012-09-13

HHGTTG some of my most read books =)

agis68 (author)2012-09-11

anonther one for school project! iam try to find the

naplatki (author)2012-09-11

Super idea on constructing final loader. I thank very

tkamsker (author)2012-09-10

I was building the same and did connect it with the
kit ,.. but can you explain me why you need this hughe heat sink ? Is there an tecnical reason for that ,..
Would be nice because ill then build it fitting for canteenkit

scraptopower (author)tkamsker2012-09-10

Not really, I just thought it would help collect the heat better. It does need to be kept cool on the cold side tohough, which can be hard to do in a small space.

TheSwedishFish (author)2012-09-10

This was so great, scraptopower! I loved it, faved it, and voted for it :) And am going to give it a shot soon. I have a thought, about developing it further so as to possibly use a composting box as a power source, with all the heat developed by biological activity? Say, in a greenhouse? 'Twould be a good use, what say you to the idea and its feasibility?
Aiden :)

Chico da Rave (author)2012-09-09

I'm thinking... if put another pan in the other way? With the opening for down side...

hannahbeader (author)2012-09-09

Vincent 7520: there is a stove online called the BIOLITE Stove. Has a USB charger built on the side of a backpacking stove, weights around 25g boils ware in less than 15 minutes. Quite the little deal.caa

lornfate (author)2012-09-09

Very useful! Thanks for the share...

Adam Manick (author)2012-09-09

Cool Instructable! Actually the mars rover Curiosity uses a similar device to power itself. The only difference is Curiosity uses heat from uranium as a heat source, but it still goes through a thermoelectric module to generate power.

Wazzupdoc (author)Adam Manick2012-09-09

I think they used Plutonium (mucho calor!).

sdobbie (author)2012-09-09


vincent7520 (author)2012-09-06

very neat … 

now is there any way the whole thing can be made smaller in order to carry it when backpacking or other outdoors activities ?

congratulations again ! :)

NightLord (author)2012-09-06

Have you tried if it worked without heatsink on the bottom?

scraptopower (author)NightLord2012-09-06

It will work but it can damage the peliters becuase you get more hot spots and uneven heating.

Josehf Murchison (author)2012-09-05

Is the TEC-12706 Peltier Modules the same units used in 12 volt coolers.

I don't know to be honest, but I think the ones in coolers are actually bigger.

DoctorDv (author)2012-09-04

This is so neat!

blkhawk (author)2012-09-04

I think that your project should be under the Technology category.

scraptopower (author)blkhawk2012-09-04

Maybe! It could fit in both....

kelseymh (author)scraptopower2012-09-04

It does fit in both (and is awesome :-). Unfortunately, the I'bles database doesn't support multiple classifications. I think your choice of "energy" is as good as "technology": it's more focused on the application than on the technique.

About This Instructable



Bio: Scrap To Power - check out my website for more projects
More by scraptopower:Thermoelectric USB charger - off grid electricity.Tetra Pak Bird Box Idea.Stripboard track cutter
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