FlameStower - USB charger powered by fire | Hacker News Reader

FlameStower - USB charger powered by fire

kickstarter.com

109 pointspisarzp82 comments

I think they got the idea right, but designed it around the wrong source first. Using fuel to power my devices means I need to carry more fuel with me. Why do that when I can just carry cell phone backup batteries like this one: http://mylimeade.com/

Instead this should have been designed around something I can throw in a campfire with some sort of protective spiral metal cabling to snake out of the fire to a box with a USB connector. The metal cabling could be similar to those used on high temperature oven thermometers.

You need a temperature delta to generate the electricity. Where is the cool sink in your proposal?

The cold sink is the water. Water has a specific heat capacity of 4.2 J/g/K, so its temperature isn't going to rise nearly as fast as the hot side of the device, and you need to provide even more energy to get the cold side past 100F...

The cable isn't likely to be the limiting feature here. The method of energy conversion doesn't just require heat, it requires a temperature gradient across the device. Here they're putting the tip in the fire to heat it, and the little bowl at the back full of water is used to cool the other end, thus getting a good temperature difference.

In contrast, throwing hte whole thing into the fire might work briefly while the heating was uneven, and the water hadn't all boiled off, but as soon as it reaches the same temp all over, no more power. And if it's all in the fire, even the water evaporative cooling isn't going to help much, vs when it's out of the direct flame/hot air stream at the edge.

I imagine you could design a in-fire version using a heatpipe to transfer energy out to a radiator/cooler somewhere, but that would be much more fragile and/or expensive.

What we really need is MEMS (or at least, really teeny, zero-maintenance) Stirling engines :)

> What we really need is MEMS (or at least, really teeny, zero-maintenance) Stirling engines :)

Really teeny:

http://www.popsci.com/science/article/2011-12/worlds-smalles...

MEMS (or stirling engines) don't help you there either -- as long as it's all in the fire, you have trouble extracting energy.

All heat engines run off of a temperature gradient, which is limited by Carnot's theorem to a maximum efficiency of (1 - Hot/Cold). If your heat source temperature is the same as your heat sink temperature, you get zero energy out of it.

The bigger the difference between the heat source and heat sink in your engine, the more energy you can extract.

Fully agree, the only small remark being that it's

η = 1 - Tcold/Thot

and to put in perspective: If your metal rod on one side of the peltier element (that's inside the device) is at 150°C = 302° = 423K and the cold side (water reservoir) is at 20°C = 68°F = 293K the maximum achievable efficiency is 30%.

In practice you'll waste a lot of energy (probably the flame outputs about a kilowatt of power, normally you'd comfortably use it to heat a kettle of water or canned spaghetty or...) for a meager 2W or 3W of power to your cellphone. That's because the energy transfer from a flame to a simple rod is very, very inefficient.

Ooops, I didn't mean to imply that MEMS/stirling engines would eliminate the gradient problem, it was something of a after-thought that they would be more efficient than the Seebeck junction.

I would still be concerned about the cable though. If it uses a rugged metal cable, then the worse case scenario is that it stops generating power when your fire gets a little out of control. If you're just using the standard rubber insulated cable, then you might ruin your cable and be SOL.

Thanks for the correction. I'm wondering if it can be two sides where you can put one side in a bucket of water (fetched from a nearby river or lake or created from melted snow water)

For a given weight/volume surely a gas canister works out as more energy than a backup battery?

Liquid fuels are even better than compressed butane and propane, but whether they beat lithium-ion batteries depends a lot on how efficient the conversion is to electricity.

Wait I'm confused, where does fuel come into this? All you need to start a campfire is a bit of flint and kindling.

> Instead this should have been designed around something I can throw in a campfire with some sort of protective spiral metal cabling to snake out of the fire to a box with a USB connector.

That won't work, see:

http://en.wikipedia.org/wiki/Thermal_efficiency

Your problem is that the sink capacity of your device is closely related to its mass so unless you let something change phase (for instance, water evaporation) you're going to run out of capacity to store the heat before you have your phone charged. This will result in a lack-of-temperature-gradient which means you will no longer produce power. Compare with a Peltier element that is kept equally hot on both sides or equally cold.

could have something you put in the fire, with copper pipes coming out to a water turbine outside of the fire.

You don't need to bring fuel, assuming there's wood around you to burn.

First thought: "Awesome - power for phone if everything goes to hell."

Second thought: "Wait, if everything goes to hell, there's not going to be any cell service."

Third thought: "Oh well, at least I'll have Candy Crush."

Perfect for using your offline cached copy of Wikipedia to recreate civilization after the apocalypse?

Maybe? It'd probably harder than you think: https://www.youtube.com/watch?v=BVxOb8-d7Ic

I think that is the whole point of bringing wikipedia along. Pretty sure you could reconstruct most of civilization from it...

Not sure, it's high on modern theoretical content but not very on low-tech practicals, e.g. no information on how to go about prospecting for copper or iron.

You won't need to prospect for iron or copper if civilization collapsed, the fact of the matter is we could never be "bombed back to the stone age" as there is soooo much processed iron just lying around - everywhere.

We just need technicals on recycling and smelting, cooling, rolling, machining, etc.

Myself and a couple other guys did the due-dillegence for a proposed documentary about Stone Age to building a functional electric calculator.

The starting point would have various ores as they came from the Earth.

Glass and metal working are key.

Altenator generator howto http://alumni.media.mit.edu/~nathan/nepal/ghatta/alternator....

Or your cached copy of OpenStreetMap to find your way around.

Hopefully the satellites will continue to operate for GPS. Could it be possible to approximate gps with ground radio stations (cell phones)?

GPS relies (heavily) on the satellites knowing their own orbits, which they get from a ground station, which means the satellites would very quickly get very inaccurate (and GPS with 200km accuracy is somewhat useless).

Get into amateur radio and you'll be one of the most useful people around with everything goes to hell.

I brought a BioLite stove with me on a recent camping trip and loved it. That had other advantages: easy to get a fire going during a very rainy week, no fuel to carry (in the White Mountain National Forest, anyway) and it was pretty easy to cook with.

USB charging didn't seem all that useful at first, but with a USB-rechargeable LED lantern it ended up being great. If that's all you really needed, you could get it from the FlameStower without the battery + fan machinery of the BioLite, I guess.

I've been having an internal struggle regarding the purchase of a BioLite stove. The primary reason I haven't is because of it's weight. As a backpacker, the stove is just way too heavy to carry on a trip (weekend trips, fine - but anything longer it would have to stay behind).

The FlameStower seems much more practical for longer trips because of it's weight / bulk.

Agreed. I saw the BioLite setup at Maker Faire this weekend. They have some cool products but at 33oz the stove is too heavy for my pack. This one is only 7oz.

Same - been on the fence about the biolite because it's only paying for the weight if you're 100% wood based on your trip.

This kind of makes that decision easy I think. The design seems nice, and the fact that it folds is doubly so. In backpacking your limits are in both weight and volume.

I'd like to see some reviews of ruggedness - the main thing I'm concerned about is what happens to the part of my USB cord that's plugged into the unit - it may be designed for high heat, but an average apple plug probably isn't.

Yeah, I won't argue that it's heavy.

I haven't done any backpacking with it yet -- though if I did, I probably wouldn't be taking anything I could charge via USB anyway. (The aforementioned USB lantern isn't exactly light either.)

https://www.globetrotter.de/outdoor-kueche/sturmkocher-spiri...

well the Biolite seems to be a top notch stove plus it charges your devices. The link above are comments of buyers, nearly all positive. For a stove you prefer gas?

The biolite weights 33oz. My MSR pocket rocket weighs 3oz, + 2-8 oz for the fuel. (I generally take 4oz for short trips). Even with an external battery pack I could still be almost 1lb lighter than the biolite.

Biolite is totally cool, but 2lbs is a LOT for backpacking, you can get tents lighter than that.

I recently bought a Biolite. It's a really great product and I love it, but you are right, it isn't the lightest things. I think it's perfect for those shorter trips where weight doesn't matter as much. However, it won't fully replace a good gas/gasoline stove.

Last year there was the PowerPot, which is the same principle on the bottom of a cooking pot http://www.kickstarter.com/projects/david-toledo/the-powerpo...

I must say the powerpot looks far more sensible design.

Totally agree. One less thing to carry.

My buddy is the VP of Web/Marketing there (Power Practical). Their Kickstarter last year went really well. Here's a link to their current product page: http://www.thepowerpot.com/

another similiar project: http://www.biolitestove.com/

I own one of these and it is fantastic, even if you don't use it to charge your phone (which I do) you get to scavenge fuel instead of carrying it and that vortex of flame boils water only slightly slower than most normal portable camp stoves and it is just damn cool to look at.

these are great - also good for starting campfires

There's also the tPOD1 which would be less expensive, it operates off tea candles...

http://www.buytpod.com/

http://www.kickstarter.com/projects/tpod1/tpod1-thermoelectr...

$50

The tPOD5 can charge a smartphone, it's a bit more expensive, and doesn't run on tea candles, you put it over a camp stove.

Point is, these things exist, this kickstarter doesn't seem to improve on any of them except perhaps make the designs cheaper, but they cost more. I'm sure they can make a nice profit on these devices if they sell, and if they can handle their manufacturing costs. If not, it would be cheaper to buy one of the alternatives and ship it to people instead of running your factory.

Stoves with built-in USB chargers already exist as a commerical product. For example, check out http://www.rei.com/product/846334/biolite-wood-burning-camps...

A DIY version by Timo Noko [1]. The same guy has been tinkering also with some other interesting stuff [2].

[1] http://www.youtube.com/watch?v=R1A5qc872Ks [2] http://koti.welho.com/tnoko/

And here I was hoping I could finally buy a USB powered flamethrower.

Oh man, I do and don't want to see the efficiency and carbon-output per joule generated of this device compared to actual grid energy. Not to mention particulate air pollution.

Although it will depend on what you are using for the source of your 'fire', it's not gonna look good.

This is a weird idea.

It's not intended to be an efficient clean power source. It's intended for people who want to do something like hike the Appalachian Trail and want to be able to charge their devices using the same fire they use for cooking / heat.

I'm going to get one so I can carry coal instead of batteries.

Great for the post-apocalyptic world!

Maybe good for short term natural disasters or outdoorsy types who want to stay connected.

I find some humor in that having a cell phone on and charged is still 'off the grid' (I know they meant electrical grid).

I wrote about something very similar last year, the BioLite camp stove: https://bbot.org/blog/archives/2012/06/13/biolite_camp_stove... (I'd argue that the BioLite is a better product, despite being twice as expensive, since it can run on wood.)

A problem with both products that they use the thermoelectric effect, which is miserably inefficient: The BioLite generated 2 watts from a thermal power of 5500W, for a thermodynamic efficiency of 0.036%

Solar panels, on the other hand, don't need to burn anything at all.

I see this product as having two target markets:

1) Outdoorsy people who carry fuel and find themselvea away from electricity.

2) People who are going to burn their homes down trying to recharge their iPhones during power outages.

It looks like something one could craft in Minecraft so I like it, seriously though, I've been shopping for a solar charger just in case there is some unforseeable disaster and I need to be able to keep the GPS and compass working at least. This looks like a good alternative, I looked at two of the competing products in the comments here but this one seems to me to keep the most distance between the heat source and the electrical cord while still staying out of the way of my cooking. The collapsible design seems like a good idea too.

2-3W? That means it's only a 0.5A, right? A lot of devices don't even charge properly off of a 0.5A USB source.

While they may not fast charge, many of the devices will trickle charge - simply because the original USB 2.0 spec didn't require high amperage. In fact, 2.0 spec allowed for a max of 5 'unit loads' with a unit load of 100 mA (5x 100 mA = 0.5A). Putting out more than that was against spec unless the port was specifically marked as a 'charging port' per the Battery Charging specification (you may have noticed USB ports with battery icons next to them).

It wasn't until USB 3.0 that the limits were increased. Additionally the Battery Charging spec was re-written to increase limits for charging ports.

If you can plug your device into any single USB jack on a computer (not just ones with a battery icon next to them) and it will charge, it will likely charge with this project.

In my experience, 0.5A chargers (and PC USB ports) are functionally useless for charging many modern smartphones and tablets, especially after a deep discharge. There has been many times I've put on a device to charge on a 0.5A source and come back to find its battery completely depleted. The charging will fail to keep up with the device's idle energy consumption.

If your device uses more than 0.5A for idle energy consumption, your phone's 1500mAh battery would only last 3 hours. Standby time on most smartphones is usually at least 12 hours, consuming between 100-200mA. Being able to turn the device off, and charge for 3 hours while cooking dinner and hanging out around the campfire is awesome.

This, to me, isn't very novel. Why can't you just wait for the sun to come up and carry a 140g solar panel? I suppose this may be useful in a very rare emergency situation, but otherwise, nahhh.

$ don't lie, though, and it looks like they have almost reached their goal.

It's not new at all, see this 1956 kerosene radio: http://blog.modernmechanix.com/kerosene-radio/

Some people are traveling in places where you don't get that much sun shine. Or you might what to charge your devices in some shelter where you just have a fireplace.

Congrats to Adam (and Andy) -- went to elementary/middle/high school with him, been neat to watch this product evolve over the past year on facebook.

Does anyone bother to create something similar that would help 3rd world electricity problems? oh, I forgot... they don't have smartphones.

Biolite does this. Traditional stoves produce a huge amount of smoke which is bad for people breathing it. BioLite reduces the smoke, but they found that men were usually in charge of purchasing decisions and weren't around when cooking was being done, so had no incentive to invest in the smokeless stoves. Adding electricity to the stove meant that men were more likely to buy, thus helping their family's health.

http://www.bbc.co.uk/news/business-24116000

Mobile phones are quite widespread though.

a superior technology is known for several years, but still can't make ends meet

http://www.forbes.com/sites/michaelkanellos/2013/01/31/why-a...

Mongolians will love this.

I like it but I'm curious how this compares to a hand crank like on one laptop per child

Handpower delivers about max 20W per hand to a bike with both hands. With electromechanical efficiency, 20W per hand comes out to around 1-10W per hand, depending on hand speed and generator efficiency. [1] http://www.amazon.com/Bicycling-Science-David-Gordon-Wilson/... [2] http://dspace.mit.edu/handle/1721.1/69801

Of limited practical use, but I can see it being a hot present for outdoorsy people.

I don't agree. In Africa where not all ppl have access to the electricity grid it have practical use. Together with google internet balloons plan it might be a game changer.

BioLite is making a generator/stove for daily home use in 3rd World conditions: http://www.biolitestove.com/homestove/overview/

They also have a camping version: http://www.biolitestove.com/campstove/camp-overview/features...

In a quick look it seems like the same product with different marketing slogan

Biolite appears to have been formed in 2009, so much before this product: http://en.wikipedia.org/wiki/BioLite

The tech used in either of these (http://en.wikipedia.org/wiki/Peltier_effect) has been known of since the 1800's - in the tech world we usually see it applied to exotic cooling solutions for microprocessors.

    <pedant>

Strictly speaking it's not the Peltier effect, but the Seebeck effect. One is the inverse of the other; Peltier junctions produce a temperature gradient when current is passed through, and Seebeck ones generate a current when exposed to a temperature gradient.

I think for the most part you can actually run either type in either mode, but the design and materials differ for optimal efficiency across the 2 modes.

The camping version has fold out legs, and the battery/fan pack on the side detaches and stores inside the unit for transporting. The other version has a wider base, and the pack on the side doesn't look removable (overall not as backpack friendly).

Musta been a very quick look. They are radically different products.

FlameStower is a folding unit which extends a thermocouple panel over a fire (gas stove illustrated), with a water holder for cooling.

BioLite is a cylinder which you build a wood fire in, has a thermocouple rod extending into, is air-cooled, and includes a fan (improving fire efficiency) and battery for running the fan until the thermocouple kicks in.

If by "same product" you meant the two BioLite products...

The BioLite CampStove is a small unit suitable (barely, considering size & weight) for backpacking; fuel is inserted in the top. The HomeStove is MUCH larger, and fuel is inserted in a gaping hole in the side; it is also designed (moreso than the CampStove) to minimize smoke production (very efficient burn using the fan) to reduce the large number of people (millions?) who die of cumulative smoke inhalation from cooking fires.

People in Africa aren't going to be using a USB generator. They will generate to a battery and then use that battery later. This device will _waste_ the output of the fire for the most part, it's open..not closed like a calorimeter. It's a joke of a device.

Where people don't have access to the grid they also use fire and water for other stuff. Cooking food comes to mind. It will have some limited use if it is just a thermocouple plate that sits below the pot.

sure! they'll be able to use their fire charged phones, with google's internet to see what the world is eating across the ocean on instagram.

From my understanding fuel cells are already in some limited use in Africa. At a VMWorld partners conference several years ago I spoke to a South African guy working for Wyse and he said that they had a bunch of small installations powered by fuel cells.

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