Blogroll
- ASPO The official site of the Association for the Study of Peak Oil & Gas.
- Energy Bulletin Clearing house for news regarding the peak in global energy supply.
- PowerSwitch Dedicated to raising awareness & discussion of the impending & permanent decline of cheap oil & gas supply.
- ODAC Oil Depletion Analysis Centre working to raise awareness and promote better understanding of the world's oil-depletion problem.
- Global Public Media Public service broadcasting for a post carbon world.
- Post Carbon Institute Learning to live in a low energy world.
- PeakOil.com US site and forum to educate and promote awareness of global hydrocarbon depletion.
- FEASTA The Foundation for the Economics of Sustainability
- Tradable Energy Quotas (TEQs) This website describes an effective and fair response both to climate change and oil/gas depletion
Other Blogs
User login
Personnel
Editors
Contributors
Peak Oil Primers
Archives
- September 2008
- August 2008
- July 2008
- June 2008
- May 2008
- April 2008
- March 2008
- February 2008
- January 2008
- December 2007
- November 2007
- October 2007
- September 2007
- August 2007
- July 2007
- June 2007
- May 2007
- April 2007
- March 2007
- February 2007
- January 2007
- December 2006
- November 2006
- October 2006
- September 2006
- August 2006
- July 2006
- June 2006
- May 2006
- April 2006
- March 2006
Vital Trivia
License
This work is licensed under a Creative Commons Attribution-Share Alike 3.0 United States License.
GAIA Host Collective
You are mixing terms and power vs. time. A typical car battery will produce 6000 watts, but not for an hour. Maybe for a minute. Most will have a rating in amp-hours (@ 12V).
Also, a person will generally be rated about 1/4-1/5 of a horsepower, or 150-200 watts. This is an instantaneous measurement of power which they can maintain for an extended period (a horsepower is an average rating of a steadily working horse, not the maximum a horse can pull).
To charge a car battery properly requires a certain level of current flow to dislodge sulfates. A 150 watt person will generate about 10 amps at 15 volts, not really a good charge level, but with electronic pulsators, the 10-amp rate could be used. Unfortunately, the time to charge the 100 amp-hours would require 10 hours of hard pedaling, not something most people are up to.
It motivates us to take notice of the comparison of our comfortable lifestyles to having slaves to do our work for us. Simply starting a car would require 2 slaves working for 10 minutes to recharge the power used by the starter motor at the turn of a key.
I've got an old Schwinn exercycle that uses a Motorola alternator for resistance. Anyone want to try starting my 65HP diesel tractor with it?
As you already mentioned Luis' estimate of a "manpower" is definitly too high. 150 watts is a good estimate, but this is already hard cycling. (But we probably could assume the poor man is well trained if he's charging other people's batteries for a living.) What is still missing in this considerations is, that some of the power will be diverted before it reaches the dynamo (friction). The convertion of mechanical energy to electrical energy will also not be lossless, and so won't be the charging of the battery (do lead batteries also get warm while charging? I don't know).
On the other hand is 100 Ah already a high value for a car battery (At least from a quick google research.) The typical value seems to be more like 40 to 60 Ah. The rest of your estimate seems reasonable to me, so this would result in maybe 5-7 h cycling. (Which is not too much anymore, if it can be spread over a month.)
But you'd first need a dynamo which really is capable of delivering that kind of energy. A regular bicycle dynamo won't, they are designed to work at a power level of 3 W.
I guess this is the main problem in the bicycle idea. And this is also the reason why solar power is not employed.
On the one hand it's missing knowledge. They don't know about the possiblities and even if they knew, they would still need customized solutions, which either requires good electronic knowledge and the right tools to make them, or it requires the money to buy them (usually from the west or the far east).
On the other hand, from what I heard, the concept of saving money in order to have a sum for investing into something some time in the future, to not have to spend some money even in a more distant future, is not very widely spread. This probably requires good education, which is something unfortunately missing in many african countries (I don't know about the special case of Uganda.)
On the other hand, from what I heard, the concept of saving money in order to have a sum for investing into something some time in the future, to not have to spend some money even in a more distant future, is not very widely spread.
And on yet another hand, if you're poor you can't afford to spend much on anything. I've been in places where neighborhood stores will sell an individual cigarette. Or an individual Pamper (nappy/diaper). And at the Colombia/Brazil border you could buy gasoline by the jar - small glass jars laid out on tables in the blazing sun!
On the other hand, from what I heard, the concept of saving money in order to have a sum for investing into something some time in the future, to not have to spend some money even in a more distant future, is not very widely spread. This probably requires good education, which is something unfortunately missing in many african countries (I don't know about the special case of Uganda.)
It also requires that you actually have enough money to be able to set some aside. Most of these people are barely scraping by as it is, and any money they can save will doubtless have higher priorities.
On a completely unrelated note, I find the advertisment for battery charging and "good acid" rather amusing... But I guess that's showing my misspent youth.
As you already mentioned Luis' estimate of a "manpower" is definitly too high. 150 watts is a good estimate, but this is already hard cycling.
Nope. Wrong. Lance Armstrong would pull a peak of 600 watts. I pull 400 watts and at 500+ watts I taste blood and develop a nasty hack for 2 months.
200 watts is a nice pace.
Your comment about those poorly educated
Africans being too benighted to ever think of
saving for future investment is not only
condescending, but boorish.
Do you have solar panels, stax? If not, I
have to assume that it's you are a victim of
poor education and those happy-go-lucky
cultural values that rendered you incapable
of planning for the future. I'll bet your
friends and neighbors are also betraying these
same symptoms of weak characters and weak minds.
Who said so? Watt is a power unit, not an energy unit.
I didn’t find the Amp-hour rating, hence the different numbers.
A child possibly. Jan Ullrich was widely quoted in the press as reaching 450 watts at maximum steady state. As I said most top cyclists will go over 400 watts.
Check some numbers here.
I never used a power-meter myself, but I know that a recreational rider can go over 300 watts from the experience of wealthier co-riders.
If your accounting is right then we might be talking of 6 to 8 hours at 85-90% of maximum. This isn’t physically impossible, but pedaling in a standstill is extremely painful.
That's like trying to derive average income from Bill Gates' salary. 150W sustained is typical for a reasonably healthy adult.
It is pretty easy to find the capacity of a battery, even using Google, there is no need to make meaningless statements like "stores 6000 watts". A typical figure is in the 50-100 Ah range.
LOL, it becomes increasingly clear you have no clue what you are talking about!
"Every morning, I pedal to generate electricity. The Pedal Generator I ride charges batteries, that run an inverter, that produces 110v AC, that powers LED lights, the monitor on my computer, my cell phones, and many other small battery-powered things. It is the most inspiring workout you can imagine."
"Noisy but extremely efficient, I have powered 12v CHAIN SAWS directly (yes, while someone else cut wood with them) with this unit.(1) Pedaling position was similar to a bicycle. The seat is barely visible at the upper left of the photo, and the handlebars (dropped, as on a ten speed road bike) are at the upper right.
Burst output: 25 amps at 17 volts (425 Watts) at 25 years old, and 265 Watts at 52 years old."
http://www.los-gatos.ca.us/davidbu/pedgen.html
-- I'm sure the particulars will vary widely with different setups, and of course, different riders, but it seems clear you can get both a workout and some useful charging with such a rig. Then, as someone mentioned 'kid power', there are the playground toys that have been used for pumping water in Africa and other parts, and could be used for other work. 'Kids, charge Mommy and Daddy's phones please!'
http://www.afrigadget.com/2006/06/04/playpumps/
(This also can be found through some United Nations programmes. This is just the first one that came up.
Bob Fiske
== More from David Butcher's site..
"There are many other possibilities that I can think of for this device. The efficiency and variable speed of the output are two features that can be exploited. Since it requires no fuel, and is not affected by time-of-day or weather, it would make an excellent Human-powered emergency generator, ready for any blackout. Here are some other devices that could be powered by the basic unit:
* Pedal powered charging system for portable "Jump Start" systems. These devices feature lights, air compressors, battery chargers, power meters, 12 Volt DC outlets, and of course jumper cables. The Portable Power station in the photograph was purchased at Costco for $49.95. It can be plugged directly into the 12 Volt DC output of the PPPM for charging, and then moved to wherever the power is needed. Add a small 110 Volt AC inverter (100-150 Watt) and you have everything you need for portable power. Run a laptop, TV, PA System, or any other small electrical device for hours from your stored energy.
* Pedal powered backup generator for solar electric systems or other off-grid power systems. With the newly available white LED as a light source, a few minutes of pedaling would be enough to create hours of light.
* Pedal powered biodiesel circulation pump or biodiesel transfer pump - direct drive, with no electricity and no battery. If you make biodiesel, and you wish to eliminate electric pumps from your biodiesel equipment, the Pedal Generator design is perfectly suited to circulate, agitate and then transfer a batch of biodiesel, and the power source is YOU!
* Pedal powered washing machine (this would be a tremendous workout, especially with the spin/sprint at the end!)
* Pedal powered clothes dryer (when combined with a simple solar hot-air collector, the pedals would tumble the clothes and move the air)
* Pedal powered whole-house ventilation fan (15 minutes in the evening to cool off an entire house)
* Pedal powered pump and watering system when combined with a cistern to store rainwater
* Pedal powered emergency sump pump - keep your basement dry during a power outage
* Pedal powered energy source to power astronomy equipment during stargazing. A PPPM in a pickup truck could provide a steady 60-100 Watt 12 Volt DC power supply, quietly, and keep the riders warm at the same time. Switch riders frequently to keep the whole star party warm. Don't even think of starting vehicles during the event!
* Pedal powered whole-house (central) vacuum cleaner - requires two people, of course
* Pedal powered backup circulation pump and backup air pump for tropical fish, expensive pond Koi or other animals requiring small but constant energy flows.
* Pedal powered generator, emergency bilge pump, crew-warmer and exerciser for marine use.
* Pedal powered air compressor (compressing air takes a LOT of power, and is not very efficient. This would work for small jobs only, like filling tires, staple guns, nail guns, caulking guns, small hand tools - no jackhammers!!)
* Pedal powered offset printing press, sewing machine (an ancient idea), hand tools (grinder, disk sander, buffer, drill, reciprocating saw, lathe), mulch grinder
* Pedal powered public address systems, projectors, or amplifiers for music - Radio Shack has a perfect unit for this! A single rider could power two of these with 12 Volts DC direct from the PPPM. Musicians, your green, portable PA system is finally here!
* Pedal powered Science Fair Project - anything from the efficiency of the unit, to the physiology of the rider can be studied. Human power generation is a vast subject with many possible areas of scientific exploration.
In real reality, widespread availability of tools like those, and lack of conventional energy sources, will encourage large population growth especially in developing countries.
Just makes things worse.
That's the silliest thing I've heard today.
unless by 'real reality' you're providing a 'double-positive', like "Yeah, right!"
Whatever it 'encourages', the lack of our current 'high protein' energy sources will be what no longer FACILITATES large pop. growth. The encouragement and discouragement comes from education and the stability of a society, by and large.
Bob
widespread availability of tools like those,
This is the real killer of the idea : assuming that everything else will be "the same", i.e. availability of bike parts, electric motors, 12v chain saws!!!
Another idiotic delusion (alas!)
I don't get into this post-peak survivalist speculation because a) I don't know anything and b) I think we'll adapt and carry on.
But anyways, post peak there will be a hundred million 1.5kW electric motors for the taking in the form of starter motors from cars with empty gas tanks. I also wonder how much need there will be for a state of the art semiconductor fab. Can't we just loot the nearest radioshack?
Car batteries are probably about 60Ah, or 720Wh@12V. At 200W, a cyclist could charge the battery in about four hours, maybe five considering various losses. A normal car alternator could be used to convert bike energy to 12V DC to charge the battery.
you need to also run a small dc generator, one that powers bike lights and connect it to the field on the alternator.
first it freewheels till you are going fast, suddenly you are peddeling against great resistance and generating eletrical power.
How many Kms you ride a year Bob?
Have you ever trained in a cycletrainer?
Luis,
I won't argue that there are some recreational riders capable of sustaining over 300 watts however IMO they would be very rare individuals. Your are correct about Jan Ulrich's watts and that many top professionals can also exceed 400w in a steady state. I bike race and use a power meter for training and racing. For time trialing, where average watts is the key factor in predicting your ability, I can average in excess of 315 watts for a 1 hour time trial. That puts me in the top 10% of highly trained cyclist in Ontario. I would conservativley estimate that at least 2/3rds of highly trained cyclists in North America would not be able to exceed 280 watts sustained. I've done some personal training and used power meters on average cyclists. In my experience, 200 watts for an average cyclist is a fairly good result. This would be on a 15 or 20 minute stationary test. Sustaining in excess of 150w for an extended period of time (> 1 hour) would in my opinion be beyond most of the general population, even with training.
agreed,
this is africa we are talking about.
they walk 10 miles to school, to the well, to home, they do a lot of walking and are a hardier people than us.
i am always humbled by the following two stories:
story about Vengard, by Bjorn Dhalie
In the book "the home energy diet" (page 63), the author Paul Scheckel recounts the story of a school science class with a pedal-powered generator. An offer of $10 was extended to the first student to generate 10 cents worth of electricity (1 KWH). "Not even the cockiest jock" has claimed the prize, over several years. Of course, this was in the USA, where both money and energy flow freely (for now). Moral of the story: appreciate your "energy slaves"!
Ok, 315 watts sounds plausible.
But I really do not understand the 150 watts claim. A rider of my weight would not be able to pedal over walk-speed on a climb without exceeding 150 watts.
Last year I climbed a 23 Km 0.7% average gradient mountain just under 2 hours. My average power output was somewhere between 235-250 watts. I'm a very lousy rider, dozens of others arrived before me.
Moreover, VO2max and Lactate tests are usually performed by starting at 100-150 watts and increasing on 25/15 watts intervals. Check Performance Cycling by David Morris on this.
Luis,
You touch on a good point. Watts generated while climbing are always higher than watts generated on flatter terrain. You would think proper gearing could negate any impact climbing would have on watts. I've done a lot reading on this and I am still not convinced that the power readings I get while climbing can be compared to my power readings on flatter terrain. My maximum sustained watts for a 2 hour climb (320) are similar to my watts for a 1 hour flat time trial (322). My watts for a 45 minute climb (335) are 13 watts higher than my 1 hour time trial or stationary cycling.
Anyway enough blathering on. The watts you generated on a 2 hour climb are pretty good. If the dozen of riders ahead of you were considerably lighter than you, they could get there faster with lower average watts. 10lbs between me and a teammate translated into a 5 minute difference on the same climb doing the same average power. However I'd stand by the estimate of 150 watts being a challenge for most for an extended period of time. I've done 24 hour bike races and, while not using a power meter, I'd bet I didn't average much more than 150watts after 4 or 5 hours on the bike.
explanation:
one would think there would be no difference in output TT on the flat and climbing.
however the same output on the flat equates to faster and hence more air resistance.
air resistance being the greater enemy on the flat means riding position is key and adopting a position that sacrifices ease of breathing for more aerodynamics will produce a faster time even if wattage is lowered.
climbing while riding "on the tops" allows for more open breathing hence higher wattage and since the speed is lower this extra power is not wasted in overcoming air resistance to the same degree on the flat.. aerodynamics while climbing are less important
Boris
London
0.7% at 12kph running at 250 watts?.. i think you mean 7%
btw that time is not good..you are a lousy cyclist ;-)
Boris
London
Let me try my hand at this. I have a 12 X 7 ft pontoon fishing boat with a 3 hp electric. Powered by 4 deep cycle marine batteries. The batteries are rated at 900 cranking amps and 150 Amp hours.
At full power the motor is rated at 2200 watts. 50 volts and 2200 watts is a 44 amp current drain. I normally operate at 10 to 20 amp range for max 4 hours. 20 amps for 4 hours is 80 amp hours, then recharge.
A battery rated at 150 amp hours should theoretically support 10 amps for 15 hours. That is 120 watts for 15 hours or 1.8 K. watt-hours. So with 4 batteries I have the equivalent of 7.2 K. watt-hours of storage capacity.
The boat has built in charging, 4 individual chargers 3 X 10 amps and 1 X 5 amps. Why, I don’t know. The 5 amp charger ruined its batter first (Sulfate) so I replaced it with a single 12 Amp charger. I use the 5 amp for a garden tractor battery for operating accessories. Works great.
I think there is a tendency to overestimate capability in this regard..
even top pro readings are often for singular efforts on a single day and may not represent in and out every day levels. some power readings are negated by sitting in the pack drafting thus may not represent the ability to sustain that level for 5 hours or so.
sustaining 100watts for hours at a end is still a ask for most people..thou practice improves fittness i guess
I back up you stationary "pain" statement.. thou the term uncomfortable is probably more apt.
cycling while stationary is problematic as the heat generated by the body is not cooled by moving through air... sustaining more than a hour on the "rollers" is not recommended.
Boris
London
You said "a 500 A, 12 V battery will store 6000 watts". You used a power unit instead of an energy unit. Gotta be careful about unit analysis!
It motivates us to take notice of the comparison of our comfortable lifestyles to having slaves to do our work for us.
Which has been brought up time to time here on TOD. Quite often actually. Personally I am quite fond of pointing out how, for the sum of money of (whatever a 150 watt solar panel is going for at the time) I have the energy equivalent of a slave whenever the sun shines. Not a bad deal.
Interesting claim, but I don't buy it. People used to start cars, tractors, etc. by themselves with a crank and I would start my old VW Beetle all the time by giving a good push on the doorframe to get it rolling, jumping in, and dropping the clutch out.
--K
Mundus Vult Decipi
Not to mention that one or two good pulls on our 1958 80hp Mercury outboard is enough to start it. Although when it decides to be more troublesome, I wouldn't mind having two slaves to haul on that rope . . . .
frankly a sustained average untrained cyclist is in the 100 watt bracket..even 150 watts is optimistic.. but point taken.
however i have seen more effective "tandem cycle" charging of a car battery powered sound system
Boris
London
My car typically starts in 1 second. 600 amp-seconds @ 12 volts = 7200 J. At 100 W/human, roughly 1.2 minutes of human labor.
Starter motors are typically around 1.5 kilowatts. They are low efficiency to save money because they only run for 10 seconds max so waste heat isn't a problem.