Commercially Available Bike Generators Are Not Sustainable (2011)
solar.lowtechmagazine.com36 points by baud147258 5 days ago
36 points by baud147258 5 days ago
Needs "2011" in the title. For example the section about friction drive hasn't been true for about a decade now
Not to mention they’re talking about lead-acid batteries, which have been replaced for pretty much every application, except (for now) starter motor batteries for combustion vehicles, by the various lithium batteries.
To be fair (as a joke), it's from Low Tech Magazine. Lithium batteries are too high-tech for them. They want you to power your mechanical blender, mixer, and other machines with a drive belt. Turn the drum of your washing machine with a wood fire heating the water.
Solar panels I think are too high tech for them.
I remember reading about low tech efficient cook stoves for poor countries and thinking the misses would rather have an induction burner, microwave, and an ice chest running off a solar panel.
The server the article is being hosted on is battery powered via solar. You can see it's charge percent on any page the server sends back to you.
> the misses would rather have an induction burner, microwave, and an ice chest running off a solar panel.
Those would definitely be hits.
Also, solar panels are old. Bell Labs demonstrated the first practical silicon solar cell in 1954. At some point, you're just trying to split (possibly nonexistent) hairs for an aesthetic, as opposed to making a principled stand against technology.
https://www.aps.org/apsnews/2009/04/bell-labs-silicon-solar-...
Nobody would (or should, at least) be using a lead-acid battery for this in 2026, either.
Full-cycle efficiency should be higher now. And the inverter. And the generator.
Might have changed their attitude since then as they posted in 2022 about a DIY guide on making a bike generator: https://solar.lowtechmagazine.com/2022/03/how-to-build-a-pra...
I thought he was posting about some retro product until I saw the USB ports in the energy delivery. Weird that he edited his photos to look like that, and used retro components otherwise.
I think the photos look like that to achieve a very small file size. The whole site is hosted and a small solar and battery powered server, so every MB matters.
What do you expect from idiot hipsters incapable of basic math and science, and who generally have no idea what the hell they're talking about, just building stuff well enough to take a few pictures?
Some quotes:
"Off-grid solar PV systems often charge lead-acid batteries."
Nobody is using lead-acid anymore, which shows how out of touch these idiots are with reality. For 5, if not 10 years LiFePO4 batteries have been the best option even for DIY systems.
You lose half the power you put into them, the deeper you discharge them the more you wear them out which means you have to buy far more capacity than you need, whereas LiFePO4 you can discharge down to 10% and charge to 90% and still get thousands of cycles out of them before they degrade to maybe 80% of their nameplate capacity. You also get higher working voltage - 13-13.8v for much of the battery's state of charge. I'm not kidding when I say that from efficiency losses alone you DOUBLE your effective solar generation by switching to LiFePO4 from lead-acid.
"At the other extreme, resistance on the pedals is too high when powering a kettle or a refrigerator."
It would take three hours for the average person to put enough energy into a "perfect" kettle to get it to boil, using a "perfect" bike that could convert the roughly 100W of mechanical effort into 100W of heat in the kettle....
Between mechanical and electrical losses, heat loss in the kettle, and energy inefficiency of the human body, I would rule it nearly impossible for even some of the world's most elite cyclists to power an electric kettle long enough for it to boil.
The handcart article goes to explain at length why a multitude of other options are inferior, but then they act like an electric generator bike would provide any sort of meaningful amount of power compared to just putting a solar panel outside.
Especially if you're willing to buy used, solar is dirt cheap. You can get NEW panels 300-400W panels on clearance for ~$100. You can get a nice-but-cheap 1-1.3kWh 12v battery for about $250. A top-notch solar controller, $75-100. And that battery will fully charge from dead in one day worth of sun in non-ideal conditions...
Were people doing much with Li in 2011? I don't remember them being all that accessible until a few years later but maybe that's just when they filtered into the worlds I was in at the time.
>Nobody is using lead-acid anymore, which shows how out of touch these idiots are with reality. For 5, if not 10 years LiFePO4 batteries have been the best option even for DIY systems
Ok, but they often are lead acid batteries. I just bought an inverter off a guy with lead acid batteries. They exist like crazy all over the place because lead acid can be reconditioned effectively forever with proper equalization. If you have lots of solar and you value repairability with simple tools and simple skills lead acid still has a niche
This arguably had some relevance in 2011. In 2026, cheap solar and batteries make human-powered static devices that would benefit from the extra power of a stationary cyclist completely redundant.
Some things I would like to see are pedal controlled devices. Something like a pedal controlled wheelchair, not powered by the pedals just control the forward and back motion. My mother with sever arthritis can still pedal but has a very hard time walking. It would be a little exercise doing something that needs to be done (getting around). A pedal controlled remote control lawnmower would be nifty also.
Where I used to live an elderly gent rode a very low to ground bike. Looked a lot like the silly motorbikes some peeps do. I imagine they’re out there for sale.
A recumbent bicycle perhaps? Often has pedals ahead of the front wheel, where you lay down in a hammock or moulded seat?
Yes, there are electric recumbent trikes out there, such as the Tadpole. A friend of mine got one after he recovered from a stroke and could no longer balance on a conventional bike. He rode it to work. It got him outdoors, with "anything is better than nothing" level of exercise.
That's it!
Sorry I lacked the proper name, but yes they are about. And definitely look like they could help people certain health issues. Although getting down into it would be something to consider for older peeps.
many ebikes work this way, pedaling and the chain more or less signal the motor rather than provide meaningful power... though afaik none of them do backwards for obvious reasons
she might enjoy an etrike, though more for recreation than normal day to day
Tried one at a demo; you put in a ton of work for minimal wattage. Much better off with a decent power bank, honestly.
You could attach pedals directly to motor axle and control charging power drawn precisely to ensure smooth rotation in absence of the flywheel. It could be really small.
No, you can't. Most generators have to be spun at a thousand or several thousand RPMs to put out any sort of amount of power.
Your average inexperienced person can pedal at maybe 80rpm comfortably, but probably considers even that to be "fast."
A road cyclist with a year or so under their belt will do 100rpm if they put their mind to it and are positioned well biomechanically. Above that, to do it and be smooth and efficient, especially for any sort of sustained effort, you have to have a decent amount of experience/training.
That's well over 10x too slow.
And there's still the issue of your average person only being able to put out 100-200W past about 1-3 minutes.
So Black Mirror lied to me ?!
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