a campfire powered generator?


by Ignorantape
Tags: campfire, generator, powered
Ignorantape
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#1
May5-13, 09:50 PM
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hello,
ive been trying to figure out the best way for me to get power off grid. ive looked at solar panels and dont want to spend 300 dollars and more, and i dont want to haul a gas generator and have to pay 4 dollars per hour of use.
as a result ive been here and there all over youtube and the net looking at cool turbines and biomass generators and all that good stuff. then, the idea came to mind, why dont i take a propane tank that i have, hook a copper tube to a turbine and hook that turbine to an electric generator, fill the propane tank with water and put it on a campfire.
seems easy and cheap enough. only problem is that i was never the math and science kind of person. so, i found this forum when i was looking up faradays law and how to calculate generator output.
what im trying to figure out is if a contraption such as this would even be able to power more than a lightbulb. would i need to get a bigger magnet and coil to increase the generators output? or would i need to increase the coils rpm to accomplish that?



i was thinking to use a 5 gallon propane tank and maybe just make a waterwheel type device in an enclosure. that would spin the coil. no clue how big the coil and magnet should be. i need to charge up a 6v 150 amp hour golf cart battery with this thing.

so yea, any help would be cool. thanks alot.
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Integral
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#2
May5-13, 10:21 PM
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50 years ago, as a boy scout, we had 5 gal pails with a copper loop brazed to the side. Fill it with water, stick the loop into the fire and relatively quickly we would have 5 gal of hot water.

Seems something like that could be contrived to drive a turbine and produce electricity. Of course you would need some form of a condenser and for safety some form of control system.

Frankly for car camping you could do something like this but if you are backpacking,,, one would wonder why you are even going if you have to take a contraption like this along.

I doubt that you would want to make your turbine or generator in your garage. You would need a machine shop to achieve the speeds you would need to accomplish much. You may want to start with a drill motor, not sure where the turbine could be found.
Ignorantape
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#3
May5-13, 10:29 PM
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id be towing it behind my camper,
still, id like to make it as small as i can. i know that huge versions of these can power whole farms, etc.

Oldfart
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#4
May5-13, 10:31 PM
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a campfire powered generator?


I don't expect anyone will offer to help you, as what you plan sounds very dangerous.
Aero51
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#5
May5-13, 10:36 PM
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The most important question is how much power do you need to generate in the first place. You cant design anything without a clear set of requirements.
Ignorantape
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#6
May5-13, 10:50 PM
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http://www.youtube.com/watch?v=mFY81akSPP4
SteamKing
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#7
May5-13, 11:29 PM
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Turbines tend to be expensive items, due to all that metal which needs precise machining and whatnot.
And generators can be tricky to make, what with winding all that wire and stuff.
And making a boiler out of any old spare LPG tank. Whew! One mistake and it blows up. Not to mention all that tubing/piping to hook it all up, valves, pressure regulators and so forth. And what about feed water? These boilers don't like to run dry when they're fired up. That blowing up thing again. I hope you weren't planning on enjoying or doing anything when you went off-grid. Tending to your home-made steam plant will take up most of your time. Will some of your family or friends be available to run your plant on the second and third shifts? And don't get me started on maintenance!
russ_watters
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#8
May5-13, 11:52 PM
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In addition to the likelihood of killing yourself, there is no way you could build such a thing for less than $300 so you are probably better off with a small generator or solar panels.
sas3
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#9
May6-13, 12:19 AM
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Look into a thermoelectric generators they would be easier to build, lighter and would run quiet.
SteamKing
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May6-13, 02:54 AM
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I must say that PF folk are an ambitious lot. Wanting to scratch build electric power generators, particle accelerators, nuclear reactors, supersonic transports, and the like, all with spare parts or a few trips to the local hardware store.
sophiecentaur
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#11
May6-13, 08:04 AM
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Quote Quote by Ignorantape View Post
id be towing it behind my camper,
still, id like to make it as small as i can. i know that huge versions of these can power whole farms, etc.
Your camper is powered by a highly efficient internal combustion engine and is fitted with an (80A?) alternator. I can't think of a better (fossil fuel based) way of providing yourself with a charged 12V battery for your camping needs. It may offend you to be using highly taxed road fuel for the purpose but the superior efficiency still gives it the edge by miles. A portable petrol generator would also be a good solution - for not many tens of GBP and would provide very high convenience.
It could be a different matter if you were planning on a large-scale wood burning system and if you could get the wood for very low cost or free. Small scale steam engines are unbelievably low efficiency, though.

Of course, such a project could provide you with loads of entertainment, so it could be worth while as a way of improving the holiday experience!
Ignorantape
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#12
May6-13, 02:33 PM
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cool, so it sounds like its not a very feasible idea.
i liked that thermoelectricity stuff, might look into that.
ModusPwnd
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#13
May6-13, 02:43 PM
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It can be hard to get a lot of power out of thermoelectrics.

Check out this cool camp stove;

http://www.biolitestove.com/campstov...view/features/
QuantumPion
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#14
May6-13, 03:39 PM
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You could build a Stirling engine, they are simple, compact, and run on any heat source (wood fire, oil, gas, solar, etc). You could then use it power an old car alternator to get electricity out.
berkeman
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#15
May6-13, 04:06 PM
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Quote Quote by ModusPwnd View Post
It can be hard to get a lot of power out of thermoelectrics.

Check out this cool camp stove;

http://www.biolitestove.com/campstov...view/features/
Interesting. Are they using thermoelectrics to recharge the battery? I couldn't tell with a quick skimming of the website...
ModusPwnd
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#16
May6-13, 04:09 PM
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Yea, its a thermometric device.
http://www.biolitestove.com/campstov...-it-works/#sub
sophiecentaur
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#17
May6-13, 05:08 PM
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Quote Quote by QuantumPion View Post
You could build a Stirling engine, they are simple, compact, and run on any heat source (wood fire, oil, gas, solar, etc). You could then use it power an old car alternator to get electricity out.
And how much actual power do you get out of the sort of Stirling Engine that you can build and transport? Imo, this needs to be treated as an engineering project - it needs to perform an actual job and not just go round and round and light up a pea bulb - so the actual numbers count. It's why most people pay money for a working system when they want a proper electrical energy supply.

Weight for weight and unit cost of energy, for camping, boating etc, photovoltaic and wind generators take some beating.


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