Comment by alnwlsn
9 hours ago
I attached a generator with some supercaps and an inverter to a stationary bicycle a few years ago, and even though I mostly use it as a way to feel less guilty watching Youtube videos, it does give me a quite literal feel for some of the items on the lower end of the scale.
- Anything even even halfway approaching a toaster or something with a heater in it is essentially impossible (yes, I know about that one video).
- A vacuum cleaner can be run for about 30 seconds every couple minutes.
- LED lights are really good, you can charge up the caps for a minute and then get some minutes of light without pedaling.
- Maybe I could keep pace with a fridge, but not for a whole day.
- I can do a 3D printer with the heated bed turned off, but you have to keep pedaling for the entire print duration, so you probably wouldn't want to do a 4 hour print. I have a benchy made on 100% human power.
- A laptop and a medium sized floor fan is what I typically run most days.
- A modern laptop alone, with the battery removed and playing a video is "too easy", as is a few LED bulbs or a CFL. An incandescent isn't difficult but why would you?
- A cellphone you could probably run in your sleep
Also gives a good perspective on how much better power plants are at this than me. All I've made in 4 years could be made by my local one in about 10 seconds, and cost a few dollars.
Once I did a little bike training and looking at my power curve, I was incredibly impressed by how cheap energy is. 100W is an all day number, 200W less so, 300W is exactly 20 minutes when I do an FTP test. 400W is 4x Tour de France winner Tadej Pogačar for an hour and he's a mutant. 1 horsepower is under a minute iirc, definitely under 2. 1kW is maybe 10 seconds. So I could keep my laptop and phone charged probably indefinitely as long as I have food, but not a ton more than that.
https://velo.outsideonline.com/road/road-racing/tour-de-fran...
Where I am at least, people using less power because power because power need to profit more, is wild.
They literally had record profits the last few years, rather than being forced to lay down solar. I think power should be a global endeavor, not some local for profit business with complete regulatory capture that makes competition illegal.
Yes I'm angry, because I pay more in electric than most anywhere in the world. If I charge my care with LEVEL 2 using city provided charges, during the day, it's more expensive than gas.
Energy security is national security.
Cheap electricity means you can do things that made "no sense" with expensive electricity. (e.g. smelt aluminum)
Cheap electricity means you can underbid regions that have expensive electricity...
As Technology Connections said, "Panels that cover your electrical needs for the next 25+ years? In the Midwest, we call that a good deal!"
In 1800, humanity generated 0.3 terrawatts (TW).
Humankind generates 20 TW today. That’s a massive jump.
And everyone wants more power. It determines what society can do.
But 20 TW is a pittance in the grand scheme of the vast universe. Imagine if we were generating 100 TW or 1,000 TW.
That’s why we talk about stuff like the Kardashev Scale — type 1, 2, 3 civilization type stuff.
Electricity is not currently cheap. 20 TW is a pittance. One day humanity will reach a point where we’re generating 500 TW of power and questions of being able to smelt aluminum or make drinking water from brine seem almost like a joke. We will have flying construction drones 24/7 at that scale of energy production. At that point, we’ll be asking questions like “when will we have enough energy to terraform a planet?”
Of course, there are side effects of greater power generation such as global warming… but once again, it’s a scale thing. The universe is vast.
Slowly, we are getting there.
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I love Technology Connections, but he has no idea what discounting is in economics. Or at least he writes his videos as if he doesn't.
Most of those technologies also need uninterrupted power supplies. Something wind, solar and batteries for the next 50 years aren't.
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> They literally had record profits the last few years, rather than being forced to lay down solar. I think power should be a global endeavor, not some local for profit business with complete regulatory capture that makes competition illegal.
Sounds more like you guys should be lowering barriers to entry, not setting up a global non-profit cartel.
True. I suggested global because it allows for scale with copy/paste designs, where things like nuclear could actually become viable.
Where I am, we have a solidly aligned state government. There's no concept of consequences for anyone in power. They're paid by the local companies to pass laws to make competition legal. Some are investors. All corrupt. That's what you get with a solid political alignment.
Australia I assume?
Did you try charging an e-bike with your contraption?
I don't know what you can take of this, maybe you can see it as advance pedaling, or to get a feel for energy conversion losses. Anyways, it is the kind of harmlessly stupid idea that I would want to try just because I could.
What a ridiculous idea, I love it.
Amazing stuff, have you written up a blog post? I could see a video being a fun format for this as well. Might help people develop the intuition for watts/power consumption in a different way
Kind of, it's in bits and pieces here:
https://hackaday.io/project/191731-practical-power-cycling
and is also a few years out of date.
I did do a video back then going against the infamous "bicycle toaster challenge" video (in which I determined it was probably less real than they made it out to be). I'm nowhere as fit as those guys, so in my attempt I was only able to turn a bagel into a dry crouton over the course of an hour.
https://www.youtube.com/watch?v=AcNXp86BJ-o
Any sense what the efficiency ratio was for your setup?
I'm as curious as you to be honest - putting a strain gauge on the pedals for measuring mechanical power has been on my list for quite a while. My own (probably inaccurate) measurements right after the generator says I can get 60-70Wh in an hour, but I can get to 100Wh if I try harder. I have reason to believe my setup underestimates power because my ammeter clamps at 5A and I know I can peak over that on the down stroke of the pedal.
I've seen numbers like 250W mechanical power for an average trained cyclist, so either my setup is rather inefficient, my measurements are off, or I'm going to find out that I'm nowhere near as strong as a real cyclist.
On the other hand, the stationary bike I got originally had a rubber belt, which it would chew excessively and I eventually swapped it for a chain because it kept slipping in spite of tensioning it more, suggesting I'm hitting the thing harder than it was originally designed for (how that translates into power I'm not sure).
> I've seen numbers like 250W mechanical power for an average trained cyclist, so either my setup is rather inefficient, my measurements are off, or I'm going to find out that I'm nowhere near as strong as a real cyclist.
Cyclists' power output is sometimes reported as a 'power curve' - a chart with power on the vertical axis, and duration-of-that-power on the horizontal axis.
For example, a cyclist might be be able to produce 500W for 15 seconds; 350W for 1 minute; 270W for 10 minutes; 200W for 1 hour; and 150W for 5 hours.
Oh don’t sell yourself short. It can certainly be both! (:
Thanks for sharing the details.
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