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back to article Flat mobe battery? Just light a fire

Sick of running out of charge while on long walks, a Swedish tinkerer has crafted a thermoelectric phone charger to revive his smartphone and GPS by burning butane. Vulture South notes that the setup, posted on Instructables here, is wildly inefficient, but it's a use-in-emergency approach. As David Johansson, the creator of the …

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But you can already get.....

the Biolite camp stove, which runs off of twigs and stuff. And believe me, there is no shortage of wood in Sweden. I'll be taking one with me when I move there (finally) this year.

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FAIL

Re: But you can already get.....

There is a wooded Sweden and there is the tundra in the north. See: http://tinyurl.com/cu88ka7 I would (pun intended) see you find your twigs here.

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Re: But you can already get.....

"and stuff"

Even if there's nothing you can find in the local area, there's a chance you'll have something on you that you could use in a pinch.

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Re: But you can already get.....

for emergency it could help, but if let's say you're hiking or climbing , the -relative - weight issue would be an handicap. And if used in a relatively windy location, a correct box/cover is indispensable, just Imagine you on an emergency situation in the Alps, even in a snowy storm, and try to use such.. need refining and details. But always a good initiative to develop more.

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Mushroom

Re: But you can already get..... at a stupid cost!

A nice /expensive/ backwards toy, but not much useful power.

The Biolite is very expensive toy, to fund donation of the larger version for 3rd World households, and has a small cooking area for a camping stove; it has been tested to take ages to get hot enough to give some trivial excess power output after driving the air-intake/cooling fan up to speed, and you are not going to want to nurse it for hours to hopefully charge a portable device! You can buy several beefy Li-ion battery packs for the same price; enough to keep mobile devices running for several days!

I looked at various themo-electric power sources before, and they don't look worth the significant cost, and are still quite inefficient, so provide poor power conversion e.g. even an in-development C.H.&P. central heating design I saw could only generate a mere 500W of electricity, from many Kilo Watts of gas combustion heat, at quite a premium total price!

It would seem more efficient to make a portable fuel cell, or gas turbine generator.

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Re: But you can already get..... at a stupid cost!

I was lucky enough to meet one of the Biolite stove developers at Design West / Embedded Systems Conference two weeks ago.

He happened to be the "booth babe" nearest the stove, a few UV purifiers and other interesting gear. I asked a question, and was pleasantly surprised at a knowledgeable reply. That led to a 30 minute conversation about the capabilities and design.

The stove has a microcontroller to manage the power, optimizing the peak power extraction from the thermal generator , and setting the priority of running the fan, recharging the single A123 cell, and charging a USB device.

Power extraction from the thermal generator is much like a solar cell. Draw too little current and you give up some of the output potential. Draw too much current and the voltage sags more than the extra current gains.

The key to a stove like this is running the fan. The fan cools one side of the thermal generator, then flows around the outside of the combustion chamber to keep it cool, then feeds the flame with now-quite-hot air.

Because it uses forced air, small stuff like twigs burn intensely and completely, whereas a open twig fire will flare up and die down, always burning inefficiently. The drawback is that this is a tiny stove, so you can never move up to bigger stuff. Unless you carry wood pellets with you, you need to constantly feed it more twigs. (That's probably it's biggest problem: it's too heavy to be a backpacking stove, and too attention-seeking to be a casual camping stove.)

The thermal generator does have very low efficiency, in part to keep it reasonably light. But efficiency isn't a huge problem, especially if you treat it as a stove first. There is plenty of source heat and the 'waste' heat still goes into cooking. Now if you are treating it as an electric power source... uhggh. It will use just as much fuel (and attention) as when cooking, and its priority is running the fan and recharging the internal battery before outputting external power.

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Anonymous Coward

Re: But you can already get.....

I've designed a much smaller thermal charger with a suppository shaped fuel inlet, driven by flatulence. All you need to bring is a can of beans if you are not naturally blessed.

As long as you keep your phone hooked up to your end pipe, it will stay charged.

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Pint

Re: But you can already get.....

ah a proper human/machine interface

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Pint

Re: But you can already get.....

You can also get the Samsung E1200 sim free with a free PAYG sim for 15 quid from Tesco. Battery lasts over a month on standby. Just set your smarty to divert when unreachable. No data but hardly any size or weight to it + negligible cost.

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Butane is pointess

If you have to carry butane with you to make this huge thing work then you may as well just carry more batteries which are far more energy dense.

If you power it with found materials then this is potentially useful, but a hand crank charger might be faster and more effective.

Nothing at all new in this though... In the Seebeck effect has been used for years to provide power from heat.

In the 1950s, the Russians made a Seebeck effect collar which was fitted to kero lamps to provide power for radios.

In the 1970s, I remember some encyclopedia giving instructions on how to build a Seebeck device to power a single transistor radio.

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Holmes

Re: Butane is pointess

In general, batteries have much lower energy density than fossil fuels (including butane). The power output of a camp stove is about 3 kW. However, given low efficiency of the converter, it indeed does not make much sense economically.

It's cool, though.

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Re: Butane is pointess

You could try following the link. Obviously the guy is aware of the prior existence of devices that use the Seebeck effect, since he just bought one off the shelf. As for carrying butane, that is just for testing. As he says himself: "[...] 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."

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Anonymous Coward

Re: Butane is pointess

"In the 1970s, I remember some encyclopedia giving instructions on how to build a Seebeck device to power a single transistor radio."

World Book encyclopedia - I had a copy. They used themocouple wire and a candle flame, and a very low power AM receiver design. A modern BiTe module would do a lot better.

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Anonymous Coward

You might as well as use the nPower Peg instead.

http://www.npowerpeg.com/

Both are not very compact but at least you don't also need to bring butane with you. You also don't have to worry about starting a fire or getting burned by it.

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It's called a peltier element

I have a stack of 5 92.5W elements from eBay. Plug one into the 12v rail from a PC PSU and you'll cook eggs on one side and freeze your fingers to the other, assuming the ceramic doesn't crack first. Some overclockers have been using them to pump even more heat out of the CPU and into the heatsink.

Wildly inefficient as generators, but if it's something less like a butane torch and more like a campfire, then maybe useful.

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you can buy whined up chargers from most travel and fishing shops

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and if your taking a 30 + litre rucksack, you just spend £10 on 5 spare batteries on ebay

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Headmaster

Really!

"Whined = Wind" Love it :-)

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Re: Really!

its just wind without the h, either way mobile dyno chargers dont cost much and most of the have adaptors for all common devices

a dyno radio last 8 hours with a few turns,

a charger gives enough juice to makd a power save call

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Trollface

Not if your phone has a non replaceable battery

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its not a pain staking task finding a charger for an iphone though

http://www.pcpro.co.uk/news/380692/reactor-for-iphone-5-builds-hand-charger-into-case

http://www.amazon.co.uk/Emergency-Mobile-Phone-Iphone-Charger/dp/B001MA2YO2

and if your just going to freeride XC across scotland and desert etc on your £4000 mountain bike, its not hard to put a dyno hub on the front wheel, and use a old domestic charger for the wire adaptor to the hub

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Anonymous Coward

Re: Really!

It is one way to make sure you don't use you electronics too much; you will have to pay the price with the whiner when you need to recharge it. Anyone else have the thought of Marvin the Paranoid Android doing the whining? I'll recharge it, but you won't like it.

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Coffee/keyboard

Nobody in their right mind would buy a phone without replaceable battery.. :P

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Trollface

The things people will rig up every time Apple changes the iPhone connector...

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FAIL

Simpler to buy a spare battery

I would never buy a phone that does not have a replaceable battery. A spare battery only costs a few quid. Job done!

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Coat

Butane stove in Sweden?

Surely you wouldn't get much of a flame, butane boils at -1°C. I found a butane stove was feeble on a fine winter's morning in the south of England, I suspect Sweden is a little colder.

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Happy

Re: Butane stove in Sweden?

If you put your butane in your sleeping bag with you at night you won't experience those problems.

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Coat

Re: Butane stove in Sweden?

Confucius he say:

"Man with cannister of Butane in sleeping bag is going to Bangkok."

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Anonymous Coward

Re: Butane stove in Sweden?

"Man with gas in a sleeping bag, has a dutch oven."

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When "convenience" becomes less so...

Personal preference is a factor, but if you're a regular hiker and willing to lug all that you would be better served by a handheld dedicated GPS. Such a widget lasts 18 hours on two AA batts, and is waterproof and rugged for outdoor use, two areas the phone falls flat (pun intended).

Philosophically, how many hoops does one jump through for the "ease and convenience" of using the phone instead of a dedicated widget? Is it worth it to risk your expensive phone in the rain?

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Re: When "convenience" becomes less so...

Gps units are rubbish, map storage is 500mb and 0.00000000000000000001% of the country they are sold in, extra maps cost £40, most wont let you plan a route like google maps

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Re: When "convenience" becomes less so...

if you zoom out on the java google maps, the sat view will cover 70sq miles, unless a nexus gps comes around, your better of with your phone or a paper map

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Re: When "convenience" becomes less so...

just save offline maps with android https://support.google.com/gmm/bin/answer.py?hl=en&answer=2650218

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Re: When "convenience" becomes less so...

Or use a Nokia. Their Nokia Maps^W^W Ovi Maps^W^W Here There Everywhere^W^W^W Pants Maps^W^W... Oh, whatever they call it this week, their maps application stores everything locally meaning that it's still useful even after you leave home. I have never understood the fetish for expensively downloading high resolution satellite maps just so you can figure out which exit to take from the highway.

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Re: When "convenience" becomes less so...

its a different world when your in the middle of no where and there is no phone reception, or you are abroud and not going to pay £1000 for every mb you download

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Bah!

I was thinking "why not just use the space that thing would take up to carry spare charged batteries?" when I took another look at the pic and realized the problem with that: iPhone.

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FAIL

hello can you heat me now?

What the **** do you need a phone for if you're hiking?

How could you possibly wear a battery out?

Techobratwhine!

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Re: hello can you heat me now?

Because some of us are capable of enjoying a walk in the countryside without intentionally punishing ourselves by using only Stone Age technology. We also don't feel superior about it either.

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We have become cyborgs.

While I am not sure that a mobile phone is the best choice of technology, we are all a sort of cyborg. We are all rebuilding ourselves with the tools we carry, and have been since the first flint was knapped. Clarke and Kubrick had it right with that jump-cut from a thigh-bone used as a club to an orbiting satellite.

We cannot sense magnetic fields, so we carry a compass. All this is just another step on a long road. I've aligned a paper map using a compass, so that I can match the landscape to the map. Now we have lightweight tablets which have the built-in magnetic sensors and can display the map. I regret that some people may never realise what their tools are doing, but I remember the first time I did this with a map, and connected in my head two places, on different roads, that had seemed completely unrelated yet were about a quarter-mile apart.

Is it right that we come to depend on these machines? I prefer to know the old-style tricks they emulate, because batteries do fail. For this guy--does he work from a garden shed or is Sweden too far north--he's had the fun of solving the problem. And that might be enough reason.

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