Allotment Gardening Advice Help Chat
Chatting => Design and Construction => Topic started by: Axe Victim on January 30, 2007, 08:39
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I found this excellent site with plans for home-made wind turbines and the like....
http://www.gotwind.org/index.htm
Has anyone tried wind power on their lotty? I'm half contemplating having a go at a wind turbine to run an irrigation system...I know gravity is easier, but it might be fun!
:D
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Hi Axe
That's a cool site. It's set me thinking sounds like a skip hunt and carboot job to me I could run a small heated propagator off something like that
Worth further investigation
Cheers mate
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If you do make something keep us posted....I'd love to hear the outcome. :)
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Mmmmm, that looks good. Must show it to OH!!! Get him working on something!!
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What's the betting we cause a global shortage of old bicycle dynamos now? :lol:
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think finding them old bike alternators might prove a bit tricky in the UK. Car alternators are easy to get but as noted tend to need bit higher speeds. I do believe old muntjak has a setup using a car alternator. I built one years ago but we never fully tested it. A simple gearing system might be needed.
certainly worth looking into
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You can get the bicycle dynamos that run on the side of bike wheels (ie not the hub ones) for a fiver on e-bay...they only put out 6v x 3w...enough for lighting a shed if it's windy and you're not short sighted in gloomy conditions... :lol:
At the moment I don't understand enough about the electrics and what on earth 'rectifyers' etc. actually do....is it as simple as....
spin the alternator using wind power (however you mechanically arrange that) and connect alternator to old car battery (which wires go where?) and keep battery topped up that way...then you can run anything that would be run by a car system (cd player, cigarette lighter, lights etc.)
q. Can you 'overcharge' car batteries if they are connected to an alternator 24/7
You could run a heated propagator using one of those in-car kettles.
Also, if you reverse the input to those little 'cool boxes' that you can get in cars...do they become 'warm boxes' ?
:?
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Please can some clever devil draw out specific details of how I could use a wind turbine to power a light or heater in the greenhouse...Its costing a blooming fortune in parrafin.
I have even thought of heating bricks and burying them or possible under the bench in the greenhouse....building a frame and putting pure muck in it...would that do the trick?
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Its costing a blooming fortune in parrafin.
if you can get kerosene (domestic heating fuel) its more than half the price
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ok, couple of bits of info -
rectifiers - these are what we call 'diodes' and they take alternating current (which changes direction every half cycle) and make it direct current (DC, what batteries produce). Problem is that one diode produces pulses because it only rectifies one way. A Bridge rectifier is four diodes aranged in a special loop, and they rectify both halfs of the AC input to give a DC output. But! you then need a 'smoothing capacitor' to act as a reservoir to keep the output constant.
you cannot just connect an alternator to a battery. The charge current for a battery must be DC, so it needs a rectifier. Also, batteries need to be charged at no more than a certain percentage of their capacity, so if the battery is small and the charger big, a regulator is needed (think of this as a 'tap'). In the case of a little charger like these, and connected to a car battery, you can probably get away without a regulator, so,long as the input voltage is below 14.4v
you cant run a light or heater directly from the wind charger, its output will not be sufficient, and even if it was, the changes in wind speed would mean that the bulb would change brightness. This is therefore why we use it to charge a battery, and run everything else off the battery. Most things we want to run take more current than the wind charger gives, so the battery acts as the reservoir, we take what we need in a short burst, and then over a longer time the charger fills it back up.
as the system will be 12v, the lights / heaters etc must also be 12v, so anything designed for a car or caravan is what you should look at. Remember - heaters will be power hungry, it may take the charger a long time to bring the battery back up after a stint with the heater on.
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zak can i run my world famous been chopper with a windy thingy ? :D
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hi
Zak i have read and digested what you wrote :shock:
So with all that said, what alternator and what battery and what size fan etc. will power a 12v caravan type light in the shed on the lotty.
I realise there are many different components out there but just looking for a example of a workable system for the novice type idiot :shock: :lol:
pics and diagrams also would be a help :lol: :lol: (pushing my luck) :tongue2:
Cheers
jr
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ok, firstly - you dont power the light from the generator, you use the generator to charge the battery, and run the light off the battery. Think of a river feeding a reservoir - the river flow isnt constant, but varies, the reservoir stores the water so you can draw off a constant flow through your tap.
A bog standard car battery is ample for running the sorts of lighting you would need in a shed, especially if you use 12v flourescent lights. The output rating of the generator will determine how long it takes to recharge the battery back to full power. As an example, suppose the generator is rated at 12w, for a 12v output thats 1A. The battery typically will be rated around 30Ahr, meaning you can take 30A in an hour, or 1A for 30h. If you have discharged it down to 20Ahr, then it will take 10h to recharge. So if your lighting takes 10A (unlikely, but good example here) then you will have discharged the battery to that level in 2h. :?
so the setup is = generator - regulator - protection - battery -protection - lighting :D
the regulator is only needed to prevent the charge voltage exceeding 14.4v, and to limit current if the battery is very flat. The 'protection' in the first case consists of a fuse and a diode (the diode stops the battery discharging back through the charger, its a one way valve), the second is a fuse and a switch. :)
I cant say much about the mechanics of a generator im afraid, you would need to find the average windspeed for where you are, and work out from that the blade sizes and stuff. 'fraid its a bit of trial and error. I can tell you though that if you double the blade length you multiply the output power by a power of 4 (up to the generators limits), at least for commercial 200MW windfarms anyway :wink:
zak can i run my world famous been chopper with a windy thingy ?
i dunno, whats its requirements? maybe you need a mechanical wind power for it, like a windmill for beans! :lol:
another thing to remember is that whatever size it is, it will need to be mounted on bearings so it can move to face the wind, the heavier it is the less easily it will move!
If you consider a rutland wind charger - they are about the size of a car alternator, the blades are about a foot long, usually 3 or 4 of them. I dont know if they have any gearing inside to change the rotation speed.
Id be happy to mock a test bed version up if i had the parts, and could then test it see how it works. But ive no parts to do it with at minute.
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ooops, sorry jr, didnt read your post correctly, missed the bit about the battery. :oops: you can ignor my first sentence! :?
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just another thought, going back to the question can u keep the battery on trickle charge without damaging it , would it be possible to run a invertor so now producing 240v and run this on a daily basis without killing the battery?
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Hi Zak
Thanks for the time you took to explain that :wink:
I will look at this a bit more closely as i have too give it a go.
with what you said above about ( Ahr) then a typical caravan light12v or similar will use very little of the power stored in a typical day. for the short period of time you would need an indoor light, on a dark plot in the middle of nowhere :D but could power a radio for a few hour while you dig,mmmmmmmmmm it gets better :wink:
cheers
jr
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thats it, spot on. Lets say its a 12w bulb, that takes an amp, so a typical car battery would last around 30h. But, you may only have the light on for 15min so it would last 120h. During those 120h the generator, although not constant output, lets say gave full output of 1A for 30 of those hours, its more than refilled the battery! in fact, much of the generated energy will have been dissipated without being stored, simply because the reservoir is full!
Im going today to wire up the power feed from my solar panel and 7Ahr battery, to my weather satellite system. The solar panel in summer sun is rated around 6-8W. Should be ample duty cycle for what i need.
Be interesting to know on here if anyone does get a mock up wind genny going
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in fact, much of the generated energy will have been dissipated without being stored, simply because the reservoir is full!
...but where does it dissipate? Does the battery get warm and the hydrogen bubble off?...basically it would be getting trickle charged whenever the wind blows...is there some sort of switching device that stops you over charging the battery?
:?
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once a battery is full, it will only draw a low current 'maintenance charge' or trickle charge as its commonly called. The battery determines what current is taken, regardless of what the generator can supply. The excess energy simply becomes heat within the mechanical moving parts and the resistance of the circuit.
As such, the battery can be left to trickle charge indefinately, this in fact is a good idea as it stops the battery from self-discharging (that is, going flat on its own)
A lead acid battery will only become overcharged if it is charged at too high a voltage, hence the use of a regulator to keep the voltage to either 13.8v (trickle) or 14.4v (fast charging, not to be left at this voltage permanantly), if a battery is heavily discharged, it can try to draw a very large current from the charger, and so a resistance is included in the circuit to limit the available current and prevent damage to the circuit in this case.
Of course, with a wet battery (car type lead acid) you should carry out normal maintenance, making sure the electrolyte is topped up etc. Something i hadnt done on my scooter and found out this afternoon when i tried to start it that the battery is flat! :cry:
NOTE : all this about batteries relates to lead acid (car battery) or sealed lead acid (leisure batteries) only - nicads, niMH and LiIon batteries are entirely different!
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I had assumed we were all thinking of 'old car batteries' (being tightwads, green, and thinking it was all we could get hold of! :) )....it's all I was thinking of...simple windmill....dynamo...car battery...power....I had sort of forgotton that technology had moved on.
What would be the simplest, cheapest and most attainable set-up for an old allotmenteer?
:roll: :D :shock:
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My mate down our site has solar and wind power, he runs a fridge,a small tv, a cd player, and two whopping lights, He said it cost him next to nothing to build, so when he gets back from woofing in the derbyshire hills i might have a good look at his set up and get some wind and solar power in me garage, And will get some pics posted with info of course.
P.s he has got a queen wood burning stove to, for his rabbit and pike he likes to cook :roll:
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Does anyone know if the propeller can be made to work efficiently on a horozontal plane?
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hi denbo
ask your mate if i can move in that sounds better than my digs :lol: :lol:
nah really, get some pics so we can see his set up sounds very good.
cheers
jr
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Does anyone know if the propeller can be made to work efficiently on a horozontal plane?
no, the propeller needs to be vertical to ensure a sufficient volume of air passes it. The only 'horizontal' form that you can use, does rotate on a horizontal plane, but it very tall to get the air volume, they are commonly used as rotating signs outside garages! :D
anyone know a good cure for laryngitis? :cry:
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just another thought, going back to the question can u keep the battery on trickle charge without damaging it , would it be possible to run a invertor so now producing 240v and run this on a daily basis without killing the battery?
I would suggest you use a 'leisure' battery (carvan type ones) with a reasonbly high Ah (amp hour) rating, as these seem to handle being charged and discharged far better than a car battery. I have an 80, and two 40Ah's wired up to my panels.
Life expectancy of a battery will depend on how much you use it really, and what condition you keep it in, i.e. fully charged and fully run down from time-to-time.
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eating half dozen oranges slowly over 24 hours wil fix ya gitus :wink:
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Monty is pretty right there, use leisure batteries as these are designed for long charging periods on trickle, and shorter, but still quite long steady discharge. Car batteries are designed to be kept charged by the cars alternator, but discharged only for very short, very deep periods (ie starting). if working properly all the cars electrics are powered by the alternator when the engine is running.
leisure batteries are what i (and the industry) know as Sealed Lead Acids. They come in a huge variety, from the 40/80/120 Ahr big units used on electric vehicles/mobility scooters and big computer UPS's, down to the small ones used in alarm systems, at maybe 6v 2Ahr. I use 12v 7Ahr for my solar kit cos my panel is only small and my radios dont need much.
oh and muntjak, i dont like oranges :cry: so its been cavonia, menthol, and lemonade, oh and a few black sheep! :D
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I have been looking into wind power to. Its very interesting. Also surprising how little electric a windmill makes even if its windy!!!.
any how another site
http://www.scoraigwind.com/books/
http://windstuffnow.com/main/
These are interesting if not demoralizing
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Does anyone know if the propeller can be made to work efficiently on a horozontal plane?
There is a windmill which work upright (Deralious i think) but it has to be started. The wind will not start it spining but once going its omnidirectional and all the working gizzmos are on the floor. Saves having slip rings or wires wound around the support pole :idea:
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Just wanted to add that I found a great site for wind/solar stuff called solarwinds. I have been after a mast for my turbine for ages and they have them there for a reasonable price.
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I have been after a mast for my turbine for ages and they have them there for a reasonable price.
scaffold tubes - thats what i use for antenna masts, ideal for wind turbines. Go to an amateur radio rally to get all the fixings and guy wire/cable stay parts (a mast taller than about 20ft will need stays)
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Been trying to get a scaffold pole for ages - no joy. Just thought I'd get it all in one, and especially one that can take the stress and strain without collapsing! Been given lots of bits of poles but many wrong diameter and far too short - frustrating!
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they are a bit tricky to get hold of. I have a duralamin tube i use as one mast that cam from a jig used for lifting boats, had to go to nottingham for it.
the same people who sell the mast fixings will sell the tubes as well.
i want the riggers at work to let me have some of the mast tubes we have piled up, there 20ft long, 18inch wide, and come with climbing ladders!, they bolt together to make masts up to a few hundred foot :D