DIY thermoelectric device charges hiker's smartphone

May 03, 2013 by Nancy Owano weblog

(Phys.org) —Whether you're in a city café hunting down a spare outlet or camping and worrying about losing outside contact, the problem is the same, a smartphone about to lose power just when you need it the most. What to do? A problem-solver who is into hiking and backpacking has an answer. He shows, step to step, how to construct a portable thermoelectric emergency generator. David Johansson, who used the project-sharing site Instructables for his step by step instructions, explained how he arrived at the idea, construction, and results.

Spending several days hiking in the wild at times, he would rely on his with GPS, along with spare batteries and solar chargers. Problem is, in two words, Sweden Sun. No, in three words. Sweden Sun, Batteries.

"The sun in Sweden is not very reliable," he wrote. "When you need it as most [sic] it´s either raining or other circumstances that makes it impossible to charge with . Even when it´s clear weather it simply takes too long to charge." Batteries, he added, are good but heavy.

This video is not supported by your browser at this time.

In thinking up alternatives, he considered the idea of producing electricity from heat for USB . "I decided to build my own thermoelectric charger." One of the key goals would have to be a device small enough to carry around. He built a transportable size with a generator capable of creating voltage by heating with a gas or alcohol burner or tea lights.

"I´m using a thermoelectric module, " he said, "also called Peltier element, TEC or TEG." After much testing and experimenting, he said, he concluded he needed a powerful TEG-module.

"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."

Results exceeded his expectations. "I can charge my iPhone which was the main goal."

This is Johansson's first prototype, and he said he welcomed outside help for further improvements. "I have not yet maximized the output because I don´t want to destroy it. I think there is a huge amount of improvements that can be done."

He noted that his device can be used with a range of heat sources and power a range of products too.

He said he does not view the device as a replacement to conventional charging methods but more as a product for emergencies.

"How many iPhone recharges I can get from one can of gas I have not yet calculated, but maybe the total weight is less than batteries which is a bit interesting!"

Explore further: Intelligent façades generating electricity, heat and algae biomass

More information: www.instructables.com/id/Batte… ger-Powered-by-Fire/

Related Stories

Harness power of the sun with solar gadgets

Aug 26, 2009

In the past, if you wanted a solar-powered gadget, you typically had to shell out a lot of cash for something made by a company you'd never heard of. But that's starting to change, as major brands such as ...

Innovative self-cooling, thermoelectric system developed

Apr 11, 2013

Spanish researchers at the UPNA/NUP-Public University of Navarre have produced a prototype of a self-cooling thermoelectric device that achieves "free" cooling of over 30ºC in devices that give off heat. It is a piece of ...

Battery Wrapped in Solar Cells Recharges in the Sun

Mar 02, 2009

(PhysOrg.com) -- Although you can buy solar charging devices for rechargeable batteries, it would be even more convenient if batteries had built-in solar cells. Sitting in sunlight, the battery could then ...

Fujifilm breaks record with thermoelectric material

Feb 07, 2013

(Phys.org)—Photographic film maker Fujifilm has been busy this year at the Nanotech 2013 conference being held in Tokyo. First came news of bendable/roll up speakers. Now the company is showing off a new thermoelectric ...

Recommended for you

Fuel cells to connect our smartphones to the outside world

14 hours ago

The potential of hydrogen and fuel cell applications goes way beyond the development of green cars. The FCPOWEREDRBS team is determined to prove this with a Fuel Cell technology to power off-grid telecom stations. They believe ...

The state of shale

Dec 19, 2014

University of Pittsburgh researchers have shared their findings from three studies related to shale gas in a recent special issue of the journal Energy Technology, edited by Götz Veser, the Nickolas A. DeCecco Professor of Che ...

User comments : 21

Adjust slider to filter visible comments by rank

Display comments: newest first

Eikka
2 / 5 (4) May 03, 2013
Propane gas can be estimated to have 13 kWh of energy per kg, so even if he gets 1% efficiency out of the device he's still beating regular NiMH and lithium batteries. 2% efficiency and it's beating all common lithium batteries.

That's how bad batteries are at storing energy.

Of course you have to factor in the weight of the device itself if you want to calculate the practical energy density.
Eikka
1.3 / 5 (3) May 03, 2013
Though of course there's some lithium cells that get up to 800 Wh/kg but they're single use only. Hearing aid batteries, coin batteries and the sort.
Isaacsname
not rated yet May 03, 2013
Neat idea.

I always wondered why hiking boots/shoes don't take advantage of the opportunity to exploit piezoelectric materials.
packrat
1 / 5 (2) May 03, 2013
You can buy small 'rocket' type stoves with this already incorporated into the side of the stoves. They come with a usb port and some of them come with a fan to make the fire hotter. . You can cook your dinner and charge a phone, etc.... at the same time. He could have saved himself some money by just doing a little net searching....
packrat
2.3 / 5 (3) May 03, 2013
@Isaccsname Haven't you seen any of the sneaker shoes that have come out in the last 20 years with flashing led lighting built into them? The piezo units haven't been efficient enough to do more than that. I don't see why you couldn't add a storage circuit into it though so if could build up enough to charge a small battery. It would take a lot of walking to charge even a tiny battery at the moment.
Wolf358
not rated yet May 03, 2013
nice reuse; you can scrounge TEG's from small coolers; the power supplies usually fail in those... the Amish use a commercial version of this to run small stove-fans, etc. see https://www.lehma...ans.aspx
fmfbrestel
not rated yet May 03, 2013
http://jxcrystals...thermopv

have been selling a stove for off-grid power and heat for a few years already. talk of a "soda can sized product" that generates 20W.

While this is neat and all, hardly ground breaking.
italba
1 / 5 (1) May 03, 2013
I don't have an iPhone but my Android smartphone needs about 3 hours to recharge. You'll need a very big gas canister to have a 3 hours fire!
Isaacsname
not rated yet May 03, 2013
@ Packrat, yes, those are what makes me think about it. Those iconic shoes used only one tiny strip of material to power the little red LED, where with modern thin film materials like PT and PZT, they could incorporate numerous layers into any sole.

I even remember coming across a patent online for tires with PZT embedded in them as well :)
holoman
1 / 5 (2) May 03, 2013
Good, lot of opportunity for thermoelectric, if funding is available.

So, the $ 500,000,000 that DOE/NSF spent on failed Solyndra using

the American people's money was wrong, but what happended ?

DID anyone at DOE/NSF go to JAIL ? NO

We need better regulation and oversite of these Agencies now.

Maybe they can give a measly $ 1,000,000 to 500 startup companies.
kris2lee
1 / 5 (1) May 04, 2013
This device can be viewed as regular battery and compared against such. Does it have more energy density than commercially produced batteries?
italba
1 / 5 (1) May 04, 2013
@holoman: Or give some decent funds to companies that where the pride of America, like Nasa, Jpl, Darpa...

p.s. Did somebody of the GM managers who ruined their own company go to jail?
alfie_null
not rated yet May 04, 2013
Would it make sense to design the heat sink such that it could be partially immersed in water?
ValeriaT
1 / 5 (2) May 04, 2013
This device can be viewed as regular battery and compared against such. Does it have more energy density than commercially produced batteries?
In connection with butane heater probably does. The energy density of butane is 46 MJ/kg, the energy density of lithium battery is ~ 1 MJ/kg. The energy efficiency of TEG > 2% is therefore sufficient to outperform the lithium battery. Of course, it's still terribly inefficient with respect to total electricity yield.
packrat
1 / 5 (2) May 04, 2013
@ Packrat, yes, those are what makes me think about it. Those iconic shoes used only one tiny strip of material to power the little red LED, where with modern thin film materials like PT and PZT, they could incorporate numerous layers into any sole.

I even remember coming across a patent online for tires with PZT embedded in them as well :)


I see you took some kid shoes apart too! If I'm not mistaken there is some company coming out with bicycle tires now that have light up sidewalls of some material that uses that stuff for power.
axemaster
not rated yet May 04, 2013
This is hurting me deep inside. Why on earth would you use a thermoelectric generator, when you can just use a small normal generator and get vastly better results? And why is this considered news? Any half competent high schooler could assemble something like this.
digitaltrails
not rated yet May 04, 2013
The Biolite product is similar, but burns twigs and uses the some of the generated power to drive a fan that forces air through the combustion chamber to get more out of the fuel - thus making twigs a viable fuel. At least that's the idea.

http://www.biolit...eatures/
Jeddy_Mctedder
2 / 5 (4) May 04, 2013
Look on the market....there is an obvious demand for a multofuel 250 watt max power commercial mini generator. it doesnt exist. it shoild. burn diesel nat gas and petrol.
Theres no need for a 1kw generator with ecomode at 250 watts when it should be designed around 250 watts. exclusively
ValeriaT
1 / 5 (2) May 05, 2013
The price and life-time of miniaturized combustion generators is probably the reason, why they're not applied in wider scale. The miniaturized combustion motors do need to run at high RMP for being efficient. Such an motors generate lotta noise, they're complex and fragile and their life time is low. But I do agree, with expansion of mobile devices there is potential hole at market for these minigenerators. The reason why these generators aren't more widespread is probably the lobby of batteries manufacturers and relatively small marketing target of people, who cannot recharge the mobiles at daily basis from grid.
JohnGee
1 / 5 (5) May 05, 2013
This is hurting me deep inside. Why on earth would you use a thermoelectric generator, when you can just use a small normal generator and get vastly better results? And why is this considered news? Any half competent high schooler could assemble something like this.
The same reason NASA does, reliability. A peltier effect device has no moving parts.

I don't think this is news worthy of this site, but I do applaud the inventor. He seems intent on improving the design. There is a niche for this product.

This product is also more likely to be used in areas where the waste heat is more likely to go towards heating a tent or cabin than to get no secondary use. There's also no reason it couldn't be designed to have the burner detached so the hot end could be placed in a fire or on a stove.
italba
1 / 5 (1) May 05, 2013
@ValeriaT: The reason why low power thermoelectric generators are not in wide use is that there is no need for them in rich countries. To substitute the electrical grid for an house you'll need at last one or two kW, we don't live in tents. In 1950, when Europe and his electric grid was almost destroyed, Philips built a small (200W) Stirling engine generators, but they could not produce it at a reasonable price. Nowadays you'll better use solar or small wind generators. You can find, anyway, small (0,7 ~ 1 kW) gasoline generators for few hundred Euro.

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.