Bike Generator with flywheel and control panel

Simple living, extreme early retirement, becoming and being wealthy, wisdom, praxis, personal growth,...
Post Reply
theanimal
Posts: 2628
Joined: Fri Jan 25, 2013 10:05 pm
Location: AK
Contact:

Bike Generator with flywheel and control panel

Post by theanimal »

In the newest article from Low Tech Magazine, they detail how to build a bike generator that has a control panel to allow for powering a variety of devices/appliances no matter what voltage they run on. It also incorporates the use of a flywheel. It uses all common parts and no welding. Total cost ~$475. I'm intrigued and am interested in building one myself as an experiment. They only use cables to allow for 5A worth of charge but are able to power appliances 15A and greater with direct cables.

https://solar.lowtechmagazine.com/2022/ ... rator.html

white belt
Posts: 1452
Joined: Sat May 21, 2011 12:15 am

Re: Bike Generator with flywheel and control panel

Post by white belt »

Very interesting. I'll be closely following along if you build one.
On the other hand, a bike generator is an excellent addition to an off-the-grid solar PV system, at least in a low-energy household. The power output of the bicycle generator does not depend on the weather, the seasons, or the time of day. Human power can provide extra energy during bad weather, which reduces the need for expensive and unsustainable batteries. That is especially useful in winter, when the solar PV system produces much less power, and when the effort required to operate the bike also keeps you warm. There is enough solar power in summer — when it’s often too hot to use a stationary bicycle.
It seems LTM's views have evolved a bit since some of the articles from 10 years ago about how a human powered pedal generator that creates electricity is way too inefficient compared to one that simply transfers mechanical energy. I like the small form factor of this.

What do you think you would power with it?

theanimal
Posts: 2628
Joined: Fri Jan 25, 2013 10:05 pm
Location: AK
Contact:

Re: Bike Generator with flywheel and control panel

Post by theanimal »

I'm glad you commented, I was thinking that you'd be interested in this as I was reading the article.

I'll have to look at it further, but if I'm able to I'd like to just hook it up directly to my battery bank. That'd be ideal, but it's not practicable as the setup they outlined would require a tremendous amount of pedaling to cover even half of daily electrical consumption. My fiancee has some cooking/baking appliances that are high energy (1000 plus W) that could serve as a good direct application. In the summer, chest freezers could be another good option. I have them on a timer so they run for only 2-3 hrs per day. Most of the time solar covers this just fine, but during the rainy season it might be a good alternative.

white belt
Posts: 1452
Joined: Sat May 21, 2011 12:15 am

Re: Bike Generator with flywheel and control panel

Post by white belt »

A huge underrated aspect of this bike generator is that it is an actual exercise bike! This means it can be used by a normal person exercising who may not really care about living off grid or all the energy stuff; they just want to ride an exercise bike because that's what they are accustomed to doing at a gym or at home. Think of all the people right now pedaling away using typical exercise bikes that can't capture any of the energy transferred. One tricky aspect is figuring out how to capture that energy with minimum efficiency loss (what one loses in efficiency by converting mechanical to electricity, one gains in versatility since electricity can be stored and transmitted over distances to power a variety of things). Also, I think a version with adjustable gears is still necessary to add more practicality. The author points out that there are many efficiency gains to still be had by going with a drive design rather than chain, but he was aiming for simplicity and scalability.

In an ideal world, people would realize that driving a car to then sit on a bike at the gym is dumb, but in the meantime this could be the start of fantastic bridge solution. Group spinning classes are really popular, so perhaps there is a way to set up a group spinning experience that caters to the wealthy urban eco yuppies? Market it as reducing emissions by creating zero carbon electricity or something like that to tap into the virtue signalling tendencies. Figure out something to use the bursts of electricity towards that is useful without needing batteries or having to convert to AC. This would probably require moving past a prototype design and improving the aesthetics.

Maybe this is a bit OT, but I also have some ideas for a broader human powered electricity generator gym. Here's what I'd put in it:

-Bike generator with flywheel
-Flywheel lifting platform
-Universal flywheel machine
-Curve treadmill
-Rower


I think one could adapt the same energy capturing mechanisms from the bicycle to an exercise flywheel platform design.* Those flywheel platforms are becoming popular because they allow one to train lower body exercises (among other things) with a ton of resistance but without the need for any weights. I also theorize that one could convert an old school universal machine to run on flywheels and again use the same energy capturing mechanism, since basically it's just a bunch of pulleys at different angles. The curve treadmills are essentially human powered treadmills, so it should be relatively straight forward to capture some of the energy.

* = https://www.youtube.com/watch?v=J0Xf-ozmDrQ
Last edited by white belt on Mon Mar 07, 2022 6:29 pm, edited 1 time in total.

User avatar
mountainFrugal
Posts: 1125
Joined: Fri May 07, 2021 2:26 pm

Re: Bike Generator with flywheel and control panel

Post by mountainFrugal »

I have been thinking about this since getting my trainer last year.

This is one of the most practical solutions that balances just a few electronics with non-custom set-ups for the bike itself. You can get fancier with a belt drive from wheel to motor/alternator or whatever your mech/elec conversion machine is if you need something more efficient:
https://www.youtube.com/watch?v=x1hMVqg8VZY

The same build as written instructions: https://genesgreenmachine.com/best-desi ... generator/
Erg Rower generator design that uses flywheels: https://genesgreenmachine.com/erg-rower-generator/

1000W oven is going to be pretty hard to power using pedal power alone:
https://www.youtube.com/watch?v=S4O5voOCqAQ

white belt
Posts: 1452
Joined: Sat May 21, 2011 12:15 am

Re: Bike Generator with flywheel and control panel

Post by white belt »

mountainFrugal wrote:
Mon Mar 07, 2022 6:19 pm
1000W oven is going to be pretty hard to power using pedal power alone:
https://www.youtube.com/watch?v=S4O5voOCqAQ
Bakery business paired with spinning studio? I'm not sure if the energy math makes sense to go human calories -> mechanical energy -> electricity -> heat energy, but it might in an off the grid situation. It might be better to use something that can only be done with electricity.

theanimal
Posts: 2628
Joined: Fri Jan 25, 2013 10:05 pm
Location: AK
Contact:

Re: Bike Generator with flywheel and control panel

Post by theanimal »

Yes, reading further, powering anything over a few hundred watts on an individual basis doesn't seem feasible. Even closer to 100-200 W is probably pushing it for a household. This probably limits the application to things like charging phones and computers. There are some things, like chest freezers, which have very low draw when running, but start up draw would probably not be able to be overcome with a human powered setup.

The spin class is a really neat idea. A electricity generating gym paired with some other type of business (maybe indoor microgreens or hydroponic setup?) is a brilliant idea.

white belt
Posts: 1452
Joined: Sat May 21, 2011 12:15 am

Re: Bike Generator with flywheel and control panel

Post by white belt »

theanimal wrote:
Mon Mar 07, 2022 6:34 pm
The spin class is a really neat idea. A electricity generating gym paired with some other type of business (maybe indoor microgreens or hydroponic setup?) is a brilliant idea.
Microgreens, aquaculture/aquaponics, and mushroom production could all work well since they all require electricity and are indoors, but with relatively minimal square footage requirements. I know microgreens and mushrooms are both commonly grown in climate-controlled trailers, which would be easy to custom wire for such a purpose. Early morning and evenings when many people attend exercise classes also happen to be times when PV capture would be low. Just need a gazebo/roof structure for the actual bikes and the whole setup could happen in a backyard or even vacant lot. After the workout, you can give the class some small samples of what they've helped produce, with the option to buy larger quantities at a discount if they want. I'm sure word would get out on social media about the unique experience.

We'd have to hire @Ego as the instructor to ensure we get max output from each class.

Edit: Or maybe people wouldn't enjoy feeling like they are hamsters on a spinning wheel?

User avatar
Sclass
Posts: 2791
Joined: Tue Jul 10, 2012 5:15 pm
Location: Orange County, CA

Re: Bike Generator with flywheel and control panel

Post by Sclass »

I had a friend who built one of these as a physics demo for a university class. It had purely resistive loads (lightbulbs). It was very awkward to ride because the impedance match between the legs of the human and the load didn’t have enough flywheel effect. This is mentioned momentarily in your link. It’s hard to put into words but it didn’t feel smooth like riding a bike and it was awkward to pedal.

I imagine there is an entire branch of engineering to match energy flows in electrical generation.

I guess the flywheel is the simple way to get around this. I kind of recall the old stationary trainers you’d hook to your road bike had beefy flywheels on them along with a turbo fan. I’m wondering if there is a way to do this with magnetic induction and Lenz’s law. Kind of like a back EMF that turns your generator into a motor momentarily to get you through the spots where your legs don’t make much force so it feels more like a natural riding experience.

Do ebikes with pedal assist do something like this?

white belt
Posts: 1452
Joined: Sat May 21, 2011 12:15 am

Re: Bike Generator with flywheel and control panel

Post by white belt »

I'd like to try using elements of the bike generator design and adapting it to DIY exercise flywheel design like this one: https://youtu.be/om5VSJdQ0Gc

I have no idea how many watts one could generate from an exercise flywheel. Maybe it would be less because the resistance is created by applying force in the opposite direction that the flywheel is spinning? I'm assuming a friction drive can work in either direction.

User avatar
Sclass
Posts: 2791
Joined: Tue Jul 10, 2012 5:15 pm
Location: Orange County, CA

Re: Bike Generator with flywheel and control panel

Post by Sclass »

Fascinating. It’s a giant yo-yo.

J_
Posts: 883
Joined: Tue Nov 01, 2011 4:12 pm
Location: Netherlands/Austria

Re: Bike Generator with flywheel and control panel

Post by J_ »

In 2019 I build one:
Image

Its is still ready for use in my attic.
It has output AC 220v, DC 12v and USB 5v. Total costs about € 65.
As I reported earlier in the forum*, it is hard and long biking to load a battery. But still, when you have no power and are in need to listen to a radio..about...
Or want some pleasure listening a beautiful piece of music from a cd-player.. its all possible.

*
J_ wrote:
Sun Dec 13, 2020 9:57 am

Post Reply