[Peripherals] Alternitive Power for Developing Countries
info at olpc-peru.info
info at olpc-peru.info
Tue May 6 13:54:39 EDT 2008
Hello Arjun et al,
>* Cost of Alternators -- I agree they are expensive. Have you thought
about taking car alternators?
You need to choose those alternators that have low RPM (low Revolutions Per Minute).
>They give 12V and usually have built in
mechanisms for cut-off when the battery is fully charged, and also
would be easily available.
Yes, easilty available. In Peru that means that, but it doesnt mean that they have a low cost. The most popular car here is the Korean "Tico". Is everywhere, but... unlike we are... there is such demand that the alternator (new one) cost US$300 each one.
It is not possible to think in a solution based on "second hand" alternators... they work.. but how we will get 250,000 used alternators for the 250,000 XOs that will be deployed in Peru ? We need to develop prototype, pilots that can be "sourced" in a secure, stable, confident way. Wars have been lost due to the failure on the supplies chain.
>In India I've found car alternators to cost
~$100. They give about 35A output.
Maybe we will need to import them. But... who will finance this ? We can do the pilot/experiment/test/initial design. But... what then?
>... I have come to realize
that it is very difficult for a human to provide the mechanical power
needed to charge an XO, whatever they may use - legs/hands etc. This
was one of the reasons why we fundamentally wanted animals to drive
our solution and not be human powered.
That is because we are thinking in using ANY alternator. Normal car alternators (like a Toyota) need 3,000 RPM. Then you need to "pedal" (on the bike) very fast and very steady to reach those RPM that the alternator needs to start to generate energy. IF you use a LOW RMP alternator then you don't need so much mechanical movement. There are alternators (here in Peru) that works at very low RPM, just 200 RMP and they are generating huge energy, they are used for some mining equipment and they cost around US$800 each. So, technically is possible to "break" the RMP barrier, but then money is an "impossible" wall to climb.
There are many answers to this dilemma:
a) Modify a car alternator: add more magnets, add more "cooper" coiled parts. Then you will need less RPM. You will need to do this with almost ALL the car alternators that you can find. If you get an alternator that is on the 600 RMP then you are VERY NEAR to what any human been (big or small, child, woman, man) can generate.
b) Build your own alternator: import the magnets from China, very very (and very) cheap. Locally (at least in my country) we can add the cooper coils bobins. We need a good design and some testing. Add some circuits (very cheap too, any medium skilled tech here can build one) for doing the cut off, the rectification, and other electronic gadgets.
More: the bike/leg combination is not usefull because you move THE WHOLE LEG. Too much waste. Then you transfer all that spend energy to a small "flywheel" that transfer (by the chain) the movement to the rotor (that is in the back of the bike). You need to do this because you need BIG torque (initial force). In the case of the "charging batteries" there is not need to move the weight of any person so no such a need torque is needed. So, IF you use a spinning wheel (that is what I have in mind) you move just one foot and that is good enough to move a BIG wheel that will move the "rotor" on the alternator (or the pulley on the alternator). I have done the calculations and that "foot" movement can generate from 500 to 600 RPM with a very low and normal "pedaling" (treadling) rhythm. Since it is in the "border line" I think we would need to add some extra pulley system to add a little bit more RPMs.
>*Rule of thumb -- Whatever you may design, remember, as a simple rule
of thumb, that from the alternator you may use, you'd need to provide
each XO laptop about 1.5A of current at 12V for about 2hours to charge
the battery from empty to full.
I am taking note. Question: how long can the XO work with a full charged battery ?
(then we can calculate how many "alternator sets" we need for this or that school)
>It would be my suggestion to plan out the
power solution as much as in detail as possible before implementing
it, it would save you problems that you might face later on!
AMEN!!!! Base line is what we need.
Javier Rodriguez
Lima, Peru
Arjun Sarwal wrote:
> Hi Javier, Caryl and others,
>
> A few thoughts.
>
> * Cost of Alternators -- I agree they are expensive. Have you thought
> about taking car alternators? They give 12V and usually have built in
> mechanisms for cut-off when the battery is fully charged, and also
> would be easily available. In India I've found car alternators to cost
> ~$100. They give about 35A output.
>
> * I would like to see more variations of human power being explored,
> like the one Caryl has mentioned. I think it is a very interesting
> idea. However, whatever experience I have had, I have come to realize
> that it is very difficult for a human to provide the mechanical power
> needed to charge an XO, whatever they may use - legs/hands etc. This
> was one of the reasons why we fundamentally wanted animals to drive
> our solution and not be human powered.
>
> * Bicycle - Holden Bonwit, cced here was recently working on Bicycle
> powered solution at a place near Delhi. I will fish for the link he
> sent me, but they concluded that it is difficult to get enough output
> from a single dynamo to be able charge XOs
>
> * Battery -- In terms of electrical design it'd be much better to
> charge, say a 12V car battery or something rather than directly
> charging the XOs. This would basically save us hassles of having to
> put a current limiting circuit, and also car batteries or other Lead
> Acid batteries can be charged with variable current, for example they
> can sometimes get charged much faster when higher current is
> available, but the range of current the XOs can take for charging is
> limited. But we can get to specifics about electrical design etc later
> on.
>
>
>
> *Rule of thumb -- Whatever you may design, remember, as a simple rule
> of thumb, that from the alternator you may use, you'd need to provide
> each XO laptop about 1.5A of current at 12V for about 2hours to charge
> the battery from empty to full.
>
>
> I hope these help in some way. Please let me know if I can provide any
> other useful information. It would be my suggestion to plan out the
> power solution as much as in detail as possible before implementing
> it, it would save you problems that you might face later on!
>
>
> best regards
> Arjun
>
>
>> Message: 2
>> Date: Mon, 05 May 2008 14:05:32 -0400
>> From: "info at olpc-peru.info" <info at olpc-peru.info>
>> Subject: Re: [Peripherals] [support-gang] Alternitive Power for
>> Developing Countries
>> To: Mel Chua <mel at melchua.com>
>> Cc: Yama Ploskonka <yama at netoso.com>, peripherals at lists.laptop.org,
>> "Community Support Volunteers -- who help respond to \"help AT
>> laptop.org\"" <support-gang at lists.laptop.org>
>> Message-ID: <481F4C6C.7010604 at olpc-peru.info>
>> Content-Type: text/plain; charset=ISO-8859-1; format=flowed
>>
>> Hello Mel and all the people on the peripherals list,
>>
>> I have been discussing the issue of energy with other fellow on the OLPC.
>>
>> I am honest and I speak directly all the time: I think the solar energy
>> is not a realistic posibilitie in Peru: there is 100% sunny days in the
>> Andes JUST 6 months in a whole year. The worst moments are the 4 to 5
>> months were some villages (located over the 3,500 meters altitude) get
>> 100% cloudy time, very cloudy, huge rainfall. According to all the
>> investigation that I have done (I can send to anyone if you are
>> interested) the solar devices can provide from 5% to 20% IF there is not
>> a sunny day. That is a BIG problem.
>>
>> My best understanding, based on previous experience when I have work for
>> a mining company is to build a mechanical device: human driven, leg
>> driven. But not a bycecle. We have built it before but it was without
>> "cost" restrictions. It is based on a spinning wheel (I have many here
>> at my sight). But when I have put "cost" as a variable to take in
>> account then I have got the next ideas:
>>
>> a) Using alternators, in Peru, is expensive. Each alternator cost
>> US$300 aprox.
>> b) We need to import some magnets and assembly the alternator by
>> ourselves. The kids on the villages can do it as part of the
>> "experience". We must provide the alternators, the copper wire, the
>> circuit and components for the rectifier, and... the battery (battery is
>> other hard issue... short live... expensive). Assembly this "home made"
>> alternator, connecting to the spinning wheel (that can need a double
>> wheel or a "pulley" chain) can be an improvement (according to the first
>> results that we can get).
>> c) Legs are the ones that will be used. Not in a bycecle but on a
>> spinning wheel. It is totally possible generate enough energy for a
>> regular laptor with the legs, it will be easier for the XOs. Providing
>> energy for the XServers is a totally different issue, I don't agree with
>> the use of XServers. I suggest that one of the XOs MUST behave as a
>> Server (or the whole local XO network should behave as a "shared server"
>> sharing processing power... but that is a bigger task).
>> d) Need more energy? Put bigger magnets or "more" copper wire. Too
>> heavy to move? Change design: move the copper wire around the magnets.
>> Too heavy yet? Use concatenated pulleys.
>> e) Cost?: import the magnets from Korea or other asian manufacturer.
>>
>> In this moment I don't have the time to develop this pilots (because I
>> work independently, earning bread and butter for daily living, as
>> anyone, and my spare time is not good enough to attack the problem in an
>> efficient way). So I am passing this info to you (and I can discuss and
>> help more if there is someone interested in develop this prototypes).
>>
>> If we don't get an asnwer for the energy problem then we will be
>> delivering (we ARE delivering) XOs to the towns and villages that "look"
>> poor in the eyes of the occidental culture but we are forgetting that in
>> Peru the deep poverty is located in those 80,000 villages (5 million
>> people) with less than 100 families in each villages, without
>> electricity, less than FIVE HUNDRED dollars as total ANNUAL income for
>> the family (with the work of the father, mother and children from 6
>> years old). The goverment can not reach them (they reach JUST the 5,000
>> other villages that contains the rest of the peruvian population, 23
>> million people). So IF we deliver XOs just to the towns that HAVE
>> electricity then we are keeping a "STATUS QUO" that have kept the same
>> since 1821 (our "independence day" from the old spaniards conquerors).
>> We need to be part of the solution and not be part of the problem.
>>
>> We will develop this "energy" gadget (this or other one!) and then ALL
>> the responsible people will be more than happy to bring the XOs to those
>> villages. Then we, all, be very happy. Until then the "One Laptop Per
>> Children" will not be a dream.
>>
>> Best regards,
>>
>> Javier Rodriguez
>> Lima, Peru
>>
>> (just for the record: my other two nightmares are: internet connection
>> without any VSAT (or paying to the telephone company)... building
>> something like UUCP or a UUCP revival... and content, content, content).
>>
>>
>> Mel Chua wrote:
>>
>>> Moving discussion to "peripherals" list (please reply to
>>> peripherals at lists.laptop.org - subscription info at
>>> http://lists.laptop.org/listinfo/peripherals)...
>>>
>>> Chris Carrick, one of the staff members for the grassroots office in
>>> Chicago this summer (our resident mechanical engineer & green guy), will
>>> be working on getting many "ideas with prototypes built and tested" as
>>> well as "simple instructions for replicating them made available to
>>> empower the folks to generate their own power." (More of a "here's how
>>> to design your *own* power solutions!" in the end, even more than a
>>> "copy ours!" resource.) So your wish will be granted, Caryl. :)
>>>
>>> -Mel
>>>
>>> Caryl Bigenho wrote:
>>>
>>>
>>>> Yes, I thought of that too. But who would ride the bike? Where would
>>>> they go? Would it be an exercise bike? Do these folks really need more
>>>> exercise? If they, or someone in the family, will be riding around
>>>> anyway, it would work. But if they are walking most places (as the
>>>> folks in the Andes tend to do), the bicycle is not a luxury they have at
>>>> hand. Still in some places it would probably be a great idea.
>>>>
>>>> I would love to see lots of ideas with prototypes built and tested and
>>>> simple instructions for replicating them made available to empower the
>>>> folks to generate their own power. Call it "Power Empowerment!"
>>>>
>>>> > From: akonstam at sbcglobal.net
>>>> > To: support-gang at lists.laptop.org
>>>> > Date: Sun, 4 May 2008 14:40:55 -0500
>>>> > Subject: Re: [support-gang] Alternitive Power for Developing Countries
>>>> >
>>>> > On Sun, 2008-05-04 at 08:26 -0700, Caryl Bigenho wrote:
>>>> > > Hi...
>>>> > >
>>>> > > Yes, I've seen that weza treadle. The price is way to high for
>>>> > > developing countries...it costs more than the XO! I'm looking for a
>>>> > > charger that can be made inexpensively from something that may be
>>>> > > readily available. It might even be possible to retrofit one of the
>>>> > > sewing machines so it could sew and charge at the same time. That way
>>>> > > Mom could recharge Junior's XO while she was making clothes or
>>>> > > whatever!
>>>> > >
>>>> > > I wil take a look a the other list and move this idea there later this
>>>> > > morning.
>>>> > >
>>>> > > Caryl
>>>> > I am sure someone has thought of this but a bicycle would make an ideal
>>>> > charging device.
>>>> > --
>>>> > =======================================================================
>>>> > Romance, like alcohol, should be enjoyed, but should not be allowed to
>>>> > become necessary. -- Edgar Friedenberg
>>>> > =======================================================================
>>>> > Aaron Konstam telephone: (210) 656-0355 e-mail: akonstam at sbcglobal.net
>>>> >
>>>> > _______________________________________________
>>>> > support-gang mailing list
>>>> > support-gang at lists.laptop.org
>>>> > http://lists.laptop.org/listinfo/support-gang
>>>>
>>>>
>>>> ------------------------------------------------------------------------
>>>>
>>>> _______________________________________________
>>>> support-gang mailing list
>>>> support-gang at lists.laptop.org
>>>> http://lists.laptop.org/listinfo/support-gang
>>>>
>>>>
>>> _______________________________________________
>>> Peripherals mailing list
>>> Peripherals at lists.laptop.org
>>> http://lists.laptop.org/listinfo/peripherals
>>>
>>>
>>>
>>>
>>
>> ------------------------------
>>
>> Message: 3
>> Date: Mon, 5 May 2008 14:35:57 -0700
>> From: Caryl Bigenho <cbigenho at hotmail.com>
>> Subject: [Peripherals] Alternitive Power for Developing Countries
>> To: <info at olpc-peru.info>, <peripherals at lists.laptop.org>
>> Message-ID: <BLU108-W40798E83494CA5CAB3D780CCD70 at phx.gbl>
>> Content-Type: text/plain; charset="iso-8859-1"
>>
>>
>> Hello Javier Rodriguez and, all the other folks on the peripherals list,
>>
>> After seeing the creative things Arjun Sarwal is doing with cow-power in India, I started thinking of other possibilities. I remembered my grandmother's old treadle sewing machine and how excited she was to have it electrified. Later, I saw many being used 35 years ago in regions in the Yucatan where there was no electricity.
>>
>> Here is a link to a picture of what they look like. It is the one on the left.
>>
>> http://www.sil.si.edu/DigitalCollections/Trade%2DLiterature/Sewing%2DMachines/
>>
>> Many of these machines still exist. i see them at estate auctions every summer in Montana. There must be thousands throughout the world. I have twice tried bidding on just the treadle mechanism of one on ebay. I lost out on the bidding for both, but have hopes of finding one in Montana this summer.
>>
>> When I get one, I intend to try to set it up as a combination desk/power source to run an XO. If it works and doesn't cost too much to set up, it might be something that could be replicated all over the world where these old machines still exist...some probably still being used without electricity.
>>
>> Javier, have you seen any of these machines in rural Peru? Are they still being used to sew? Would there be a need to try to design it to continue to be used as a sewing machine but to generate power at the same time?
>>
>> It might also be possible to manufacture a similar mechanism, at a modest cost. But, the idea of recycling the old ones has a lot of appeal. I was also wondering if an old automobile generator could be adapted to work with it. Perhaps it would require too much torque to work.
>>
>> It may be just a crazy idea, but if cow-power works, maybe this will too. If and when I do this project, I will probably need some advice from you folks. Any suggestions for starters?
>>
>> Caryl
>>
>> BTW, Could AJ's Cow-power generator be adapted to run on Llama power? How about donkey power? Goat power?
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>> ------------------------------
>>
>> Message: 4
>> Date: Mon, 5 May 2008 23:30:06 +0000
>> From: "Alfonso de la Guarda" <alfonsodg at gmail.com>
>> Subject: Re: [Peripherals] Alternitive Power for Developing Countries
>> To: "Caryl Bigenho" <cbigenho at hotmail.com>
>> Cc: peripherals at lists.laptop.org
>> Message-ID:
>> <ed60564a0805051630t5deb641ap825b2b17c65495c8 at mail.gmail.com>
>> Content-Type: text/plain; charset="iso-8859-1"
>>
>> Hello,
>>
>> In the COS (www.cos-la.org), we are working some months ago in some options
>> for that, specially with a portable solar panel trying to reduce their cost
>> (about 60 dollars each). The device -commercially available as cell
>> charger- is really small and can charge the XO without any problems. In a
>> field test in Junin and Arahuay (Per?) the panels works great, in fact, in
>> the recent event of FLISOL in Huancayo (Junin-Peru) for the OLPC project, we
>> test the solution (commercial) between 3400 mts and 4500 mts (Ticlio).
>> Antonio Ramirez, Carlos Reinoso and who writes now are working in our breaks
>> on this task (reduce the cost for about 25 dollars each).
>>
>>
>>
>>
>> 2008/5/5 Caryl Bigenho <cbigenho at hotmail.com>:
>>
>>
>>> Hello Javier Rodriguez and, all the other folks on the peripherals list,
>>>
>>> After seeing the creative things Arjun Sarwal is doing with cow-power in
>>> India, I started thinking of other possibilities. I remembered my
>>> grandmother's old treadle sewing machine and how excited she was to have it
>>> electrified. Later, I saw many being used 35 years ago in regions in the
>>> Yucatan where there was no electricity.
>>>
>>> Here is a link to a picture of what they look like. It is the one on the
>>> left.
>>>
>>>
>>> http://www.sil.si.edu/DigitalCollections/Trade%2DLiterature/Sewing%2DMachines/
>>>
>>> Many of these machines still exist. i see them at estate auctions every
>>> summer in Montana. There must be thousands throughout the world. I have
>>> twice tried bidding on just the treadle mechanism of one on ebay. I lost out
>>> on the bidding for both, but have hopes of finding one in Montana this
>>> summer.
>>>
>>> When I get one, I intend to try to set it up as a combination desk/power
>>> source to run an XO. If it works and doesn't cost too much to set up, it
>>> might be something that could be replicated all over the world where these
>>> old machines still exist...some probably still being used without
>>> electricity.
>>>
>>> Javier, have you seen any of these machines in rural Peru? Are they still
>>> being used to sew? Would there be a need to try to design it to continue to
>>> be used as a sewing machine but to generate power at the same time?
>>>
>>> It might also be possible to manufacture a similar mechanism, at a modest
>>> cost. But, the idea of recycling the old ones has a lot of appeal. I was
>>> also wondering if an old automobile generator could be adapted to work with
>>> it. Perhaps it would require too much torque to work.
>>>
>>> It may be just a crazy idea, but if cow-power works, maybe this will too.
>>> If and when I do this project, I will probably need some advice from you
>>> folks. Any suggestions for starters?
>>>
>>> Caryl
>>>
>>> BTW, Could AJ's Cow-power generator be adapted to run on Llama power? How
>>> about donkey power? Goat power?
>>>
>>> _______________________________________________
>>> Peripherals mailing list
>>> Peripherals at lists.laptop.org
>>> http://lists.laptop.org/listinfo/peripherals
>>>
>>>
>>>
>> --
>>
>> --------------------------------
>> Alfonso de la Guarda
>> COS
>> www.cos-la.org
>> www.delaguarda.info
>> Telef. 97550914
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>> Peripherals at lists.laptop.org
>> http://lists.laptop.org/listinfo/peripherals
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>>
>> End of Peripherals Digest, Vol 6, Issue 3
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