Nice to get a moment to pull out a classic
As someone who sucks at physics, I’m convinced that Trollface has proposed so many solutions around the internet to provide free energy, but the capitalists are conspiring to sabotage him, just as they did to N.Tesla.
The other one being to shine a light on a solar panel. For bonus points you include a mirror and a vampire.
I remember the one where he uses two magnets, and the one where he wraps his head with a bag and puts a plant inside it, so he can swim with infinite O2 supply.
honestly this probably works to some degree, just that you’ll move at walking speed relative to the ground if you go up to the edge of space
So you’re on your ebike, going 15mph. Using 140w or so. You’re spending 15-20w on the drivetrain, and the remainder is entirely aerodynamic drag. You’re putting 120-125w into making wind move. You’re also losing 5-10 watts to the drive electronics and dashboard. So your total power use is 150w.
If you’re going to recharge a battery. In the same time it takes to ride, you need to get at least 150w of power into another battery. Sadly, batteries don’t actually “just cleanly charge” there are some losses, but since we’re going to take an hour to charge it, lets call it 5%. So to fill up that battery we need 157watts of input power.
Your bike, moving at a steady speed, is absorbing 150w of power. If we want another 155w of power, where is that going to come from? If we take it from… say… the front wheel, we are now absorbing another 155w of power. So to maintain the same speed, we now need to push the bike along with 305w of power. And… now we need a bike that makes 305w of power, to go the same speed we were going with 150w. … And we’re only generating 155w.
There is no free lunch. If you’re doing work, you need to get that power from somewhere.
Counterpoint:
Hills exist, go down them.
Like, the whole point of these things, at lesst as I see them, is that you get that free lunch on the way down a hill, then when going up a hill, well yeah, you still aren’t gonna like, be 1:1 be able to power right back up it, but it will be easier going up that hill than if you did not have your free energy lunch on the way down.
This then results in you not needing to expend as many literal calories going up a hill, so now, you don’t need as much food to recharge after a ride, thus you do actually on net come away with at least a portion of a ‘free lunch’, in that you don’t need as much food.
But yes, I will give you that… the overall weight added to the bike from the batteries would have to be in a manageable range, so that the uphill assistance is not just entirely used on uh, pulling its own weight.
The problem with “go down a hill” is that the LinkedIn idiot wants to use the power of one motor to generate power in the other. Regenerative braking only needs one motor and it acts as a generator when braking.
I mean… you can do regenerative breaking in a hyrbid car, where the main LiON battery is also charged from the ICE engine.
I had a hybrid Prius C that worked this way.
Roll it down a hill, far enough, in the right mode?
Recharges the main hybrid battery.
And then, you can also put it into a low power, EV only drive mode. Can’t do inclines or go fast, but you can get up to about 20mph on flat terrain.
Like, I’ve done that at least once, as a kind of makeshift jumpstart sort of thing.
Presumably, it may be possible to scale such a system down to a bicycle, or maybe moped or motorcycle.
And the LinkedIn guy specifies that there are two different batteries, which are capable of transfering power between each other.
So their system is regen braking -> bat 2 -> transfer -> bat 1 -> drive motor.
Personally, I don’t even see why you need two distinct batteries, just have a powerstation type thing with a some software that regulates power uptake and output intelligently.
Regenerative braking is not the problem. Thats been solved. The LinkedIn user is trying to invent perpetual motion
You do get about 5-10% more range with regen on an ebike, the downside is it needs to be a hub motor which sucks at climbing hills, and one with no internal clutch which means pedaling with the motor off wastes a ton of energy.
mechanical engineering student
Did not pay much attention in high school
Look out for v2.0 which also features a sail on the front which you blow to go faster.
Okay, but blowing on a sail to go faster is actually a thing. Mythbusters even stated that they did their experiment in the worst method (i.e., not using modern designs and methods), and still found that a fan on a sail could make it move. It’s not free energy, but let’s not ignore how cool sails are.
This sounded very wrong to me, so I googled and apparently they had a setup where the reflected air from the sail caused a net flow in the opposite direction allowing them to move forwards. But that is less effective than just blowing the air straight backwards without a sail.
Look for the sail car video from Veritasium. With a chain drive you can out run the wind using the principles of sail propulsion.
🤦♂️
When the battery runs out, you pull over and “pedal” to recharge the battery, then you’re good to go again!
now that is genius!
I don’t own one of these, but that sounds actually useful if for example I’m about to climb a big hill and want to pedal at a less strenuous pace (but for more time) than would be needed to overcome the slope.
That’s what gearing is for (you just go up the hill slower), but I can see the benefit to not being on the road.
Sure, but there are limits. One needs a certain amount of forward speed to maintain balance easily, and there’s a maximum speed that can be reasonably pedaled. If the hill is steep enough then in my experience reducing the gearing enough to make pedaling not too strenuous runs into the other two limits. If an e-bike can have a low battery topped off before the hill starts, then pedal-assist (at least) would take care of the need to lower the gear while going up it.
One needs a certain amount of forward speed to maintain balance easily
Not true. One just needs to practice static balance. It’s a great skill to have so everyone should learn how to do it.
Also you can use the lowest gear going almost a walking pace and climb up really steep hills. That’s how we do it on MTBs. It also requires practice and good balance.
If you need a minimum speed to maintain balance, how are you going to pedal while stationary?
Better to have active regeneration, where you pedal a bit harder on flats to top up the battery for hills.
Assisted modes already exist, and regenerative braking already exist
Yes, but is it possible to pedal and use regen breaking to recharge the battery when stationary? It does work like that in my car (plug-in hybrid) but I don’t know if bikes are the same way.
But do e-bikes have regenerative braking? I haven’t seen that. I’ve been thinking that it would just be too heavy and clunky to be worth it.
You can find YouTube videos of people experimenting with flywheel-based regenerative braking. They’re completely impractical but pretty funny to see.
It’s like 3-15% energy reclaimed, not efficient
Too heavy? You just run the motor in reverse which turns it into a generator and adds friction to do generative braking. There really isn’t any added weight.
It needs a direct drive which is more weight than the other systems
Why would it need a direct drive? A mid drive can do the same thing they just don’t usually since you’d need to gear for it. direct drives are the most efficient at regenerative braking but they aren’t the only type.
Freewheel hub would prevent it.
You would need to put the freewheel between the motor and the pedals, and have an always-spinning chain/shaft
Bikes normally have freehubs, a ratchet on the cassette (sprockets) of the rear wheel, when you stop pedalling the bike freewheels, without that the pedals would keep turning.
This makes driving a motor from the wheel impossible without heavily modifying the normal bike mechanics. That’s why regenerative braking on e bikes is rare.
Not if you have a hub motor. Those don’t interact with the gear system at all.
Only very cheap e-bikes have hub motors. They’re not a good idea precisely because they don’t interact with the gearing system. So you lose that functionality.
It’s not worth losing access to gearing just to get regenerative braking because the amount of power being used isn’t worth trying to recoup.
Yup, which is also why they’re really hard to pedal if the battery dies.
Motors are generators when run inversely:
Motors = put in power to get rotational movement
Generators = put in rotational movement to get power
You already have the heaviest parts on the ebike - motor and battery, just need some capacitors and charging circuit board which are light and not too big.
Cheap electric bikes I’ve ridden with regen breaking slow you down quite a bit.
It’s not difficult to get regenerative braking on a bike it’s just difficult to get regenerative braking on a bike that’s any good. Hub mounted motors are the least efficient type of motor because it’s just directly driving the wheel at whatever speed it can output, with no access to gear ratios. E-bikes that forgo generative breaking in favour of a more efficient motor designs achieve better speeds for any given amount of power usage.
So yeah you can absolutely do it. But it’s not a good idea for reasons that have nothing to do with the weight.
But this joke is more funny :)
The traditional method of pedaling uphill less strenuously is to drop to a lower gear. You might go slower, but I’d bet even on existing e-bikes with pedal assist, this is something that’s already pretty reasonable now days.
Gears
Incredible comment.
This is satire… right? I hope it is
Yet another “engineering student” who hasn’t learned his Newtonian physics yet. Which I’m pretty sure is covered in grade school, but you never know.
I’d go with second law of thermodynamics, but whatever.
LinkedIn has been shit posting goldmine lately.
The amount of emojis scream AI generated.
OR hear me out, AI was trained on these kind of posts. Emoji were overused in similar fashion before the AI bubble. Remember when crypto and NFT was all the rage? Crypto bros were all posting like this. And it worked on gullible people, so now AI does it too.
It’s funny how everyone thinks they’re AI detectives now.
I don’t claim to be an engineering student, why is this a bad idea? Wouldn’t he just put a “collector” of energy (like a wind turbine) on the wheels?
What happens to an object in motion when you collect its kinetic energy?
Alternators exist on a car, why not on a bike?
Regen braking is on every single electric car. But it’s incredibly inefficient and costs a lot of money to add it.
On a 60k car? Yeah it’s worth it. On an $500 ebike? No, not at all.
So we just need to put something on the bike to power the alternator…I know, an engine! Why has nobody thought of this before?!
Alternators don’t exist on electric cars. The closest is regenerative breaking, which powers the car by slowing the car down.
You can power lights or a phone charger with a dynamo connected to the wheel and minimally noticeable drag/resistance. You can recharge a drivetrain with regenerative braking which requires high end motors to use the motor like a dynamo
Yes, you can collect some of the kinetic energy and put it back into a battery with regen braking, but most of the energy put into such a system will be lost to heat/friction, drag, drivetrain inefficiencies, battery inefficiencies, recovery inefficiencies, etc.
In the lunatic post, he’s not talking about regen braking. He’s talking about using the same system that moves the vehicle to simulatneously charge a battery. Which means you’re taking some of the energy which would normally move the vehicle and shunting it into a recharging “circuit” - which introduces even more losses.
The end result would be a machine that is less efficient.
Just assume a perfect world, and we won’t loose any energy!
… Though we won’t gain any either. -,-’
Oh shit you solved it!
I was being sarcasmic.
🥵
Okay, I admittedly know nothing about this, so bear with my ignorance. Aren’t you just moving gears? It would generally be like an auto engine where you have all of these explosions that push gears. You’re just moving the gear in one direction as a click, click, click.
If you are drawing energy out of a system them that amount of energy is removed from the system. A freespinning gear won’t generate electricity. It has to be pushed, which requires more energy from the power source, and is always a net loss because of friction.
That is before the added weight of the additional batteries.
So trying to get energy back from a moving cycle will result in a less efficient bike.
Turn off the engine of your car, does it keep rolling at the same speed forever?
Where are you going to get that power on a bike? Your legs. Do you really want to peddle away to charge a battery at SIGNIFICANTLY reduced efficiency, then with even more loss of efficiency discharge the battery into an electric motor? Or do you just want your energy going directly to the wheels?
The person in the post is trying to come up with an infinite source of energy which is not possible.
Conservation of energy, basically it’s not that it wouldn’t work “at all” or appear to anyway but that it wouldn’t work as desired. You can’t recapture the power used to propel the bike because it’s being used to propel the bike. Adding a collector increases the power needed to turn the wheels and basically makes the drive battery’s job harder, so it runs less efficiently and runs out faster, battery 2 does charge and can be run from, but in the end you end up with less range due to the stacking inefficiency and energy leakage. The closest functional system to what they are talking about would be a breaking system like electric cars use.
On an e-bike you would be losing significant portion of energy from propelling the bike, friction, air drag and heat loss. You might be able to put a small amount of energy back in from pedaling, going down hills or even braking, but certainly not enough to make it perpetual.
Perpetual motion machine are physically impossible based on our current understanding of physics. Many, many people have attempted to create them, but they all fail from the reaaons above.
So last question, I promise.
A wind turbine collects the energy of the wind through movement. A gear can give more “force,” so I’m assuming more movement of something. If you have 2 different systems, one that collects the movement, or more “force,” and one that is making the bike move, why wouldn’t that be close to collecting as much as you put in. You’d have to charge occasionally, but not all of the time.
With the bike, the battery (and pedaling) is the source of your net energy output. Losses from friction to the ground and air drag will be the most significant net consumers of the energy. It doesn’t matter how the rest of that energy is moved around within the system(s) of the bike.
Ultimately, what determines the distance you travel is the capacity of the battery and what external environmental factors affect the bike and by how much. Biking at 3m/s will have less air drag than 10m/s. Friction will be affected by the surfaces you go over, with something like mud taking more energy compared to something smooth like smooth concrete.
No, they are not separate systems and you will always have significant losses of energy to friction.
Gears change how energy is transferred, but more gears means more energy loss. Always.
It could be an OK idea that just wasn’t explained right. Maybe he just wants regen braking but with one wheel for charging and the other wheel + separate battery for power at any given time. Energy would come from pedalling and hills. None of that was explained though
It would wash out. Any energy collected would be at the cost of resistance. So add fans to add wind resistance. You could collect energy from coasting and braking, but that’s just tech we’ve been using for years in cars, and it comes at the cost of movement. It actively slows you down because the energy has to come from somewhere. And since energy conversion is hardly one-to-one (loss to heat, etc), storing it into a battery and then pulling it out again means you won’t gain as much as you lose.
Energy cannot be created or destroyed. If you are generating energy, you’re taking it from somewhere, and on a bike, it’s from your forward movement.
Okay, I get that, but wouldn’t the collection be a separate system? The energy is being created by the battery, then a separate system collects the energy.
Imagine it like this, you have two glasses of water, labeled “speed” and “chemical.” You can only transfer water between glasses. And messily. It’s a sum of water, a specific weight of water between the two glasses that you own. In placing the water elsewhere, you haven’t done much besides lose a portion in the transfer. You can absolutely do what you’ve said! It will, unfortunately, just be a transfer from the speed to the chemical glass. You’d just lose a bit in the transfer.
Because its all the same energy, and the contraption just slows down.
But if you’re on a hill, you’ll go much faster, thus storing more energy.
Yes, you could collect energy while coasting down a hill, but it would slow you down. Which is fine if you want to slow down; this is the basis for regenerative braking. You might be thinking that a pinwheel spins like crazy in the wind, and that’s just free energy. But a pinwheel doesn’t store anything. To store energy, you need to add resistance, and the more you add, the more energy you collect and the harder it is to spin the wheel.
So at the end of the day, you’ve got a fan at the front of the bike that is either spinning quickly with little resistance and storing little energy or one that is spinning slowly and collecting more. And the slower it spins, the more pushback there is against your forward movement.
Despite there being two batteries, this is still a single system which uses energy to propel the bike forward and collects energy by preventing the bike from moving forward. They offset. The only way to have the energy to propel the bike is by introducing energy from another source (not related to the movement of the bike) such as a battery charged ahead of time or calorie loss of the rider (active pedaling).
Thank you for this detailed explanation. I appreciate it. That’s exactly what I was thinking about, a pinwheel.
Now you’re introducing potential energy (a hill), which will be used up (or rather be fully converted to kinetic energy) once you reach the bottom, and you’re going to need the same or more energy to go up that same hill again (depending if you take resistance into account).
We already have tech for capturing kinetic energy for later in the same battery used for driving called “Regenerative breaking” (cuz’ the motor is used as a generator in place of brakes, and you’ll need to drive said generator by capturing some of your forward motion/kinetic energy).
EDIT: In other words: You could just start on a really high hill and you’d be able to use the weight of the bike and yourself as a “battery”, never needing any actual battery/motors/wiring/etc.
It’s a bad idea because he’s essentially talking about a perpetual motion machine.
That makes sense, except the collection of the energy can be less than the energy expended, like an automobile or wind turbine. Then it could be a perpetual machine.
It would be like this:
Energy in => convert to a gear that makes it way more energy => store energy, repeat.
I must be missing something.
convert to a gear that makes it way more energy
nah, see, a gear is basically just a fancy pully. it can make it easier to pedal up a hill, but only by making you have to pedal many more times to do so. each turn of the crank arms takes less force, but you have to do it many more times. it isn’t actually reducing the energy requirement, and it isn’t multiplying your energy input.
what you’re describing here would be some kind of magic.
Gearing doesn’t make more energy output than the energy put in.
except the collection of the energy can be less than the energy expended
The collection will always be less than the energy it takes to generate it. There no magical gear or trick to change that.
Maybe you can join his team!
But I can forgive a non engineering student… its impossible.
Looks like it could even be AI style with all the emojis.
Either way, thanks I hate it.
Yea I’m 99% sure it was drafted by AI
There have been idiots before AI. People should still receive
blamecredit for their idiot ideas, instead of blaming AI for every stupid post.
Likely not only drafted with AI, but only pursued because he entered the idea into ChatGPT and asked “is this a good idea?,” and uncritically took ChatGPT’s enthusiastic support as vindication.
Seems like satire to me. Pretty funny too.
The Law of LinkedIn:
If you think it’s satire, it’s probably actually just a really stupid individual.
so, obvious reasons why this cannot work.
Is there anyway to like, siphon off the energy though? Like say, you pedaling produces 600kJ/hr. You have 400kJ/hr going into the bike to produce motion, but then 200kJ/hr goes into a battery. You’d move slower but generate stored potential energy.
I’m not really sure why you would want this, other than the concept of a self-charging electric bike, but on paper it sounds possible?
A normal bike drivetrain is around 95% efficient, which is more efficient than the Regen circuitry you could get in such a form factor. Therefore it makes more sense to use pedal power for direct propulsion since that will directly reduce battery more efficiently than using it for charging.
This is different than a series hybrid because car drivetrains are very inefficient compared to a bicycle.
You would need to output far more than twice the energy that you would get out of it and the effort to pedal would be significantly increased as you would have additional weight to the bike on top of whatever it was drawing.
Taking 1/3 if your pedal power would be like trying to bike through deep mud just to have a small boost later.
Yeah, it’s called a dynamo, used for decades for powering headlamps on bikes before small batteries and LED lights. Still, the energy generated is pretty small.
Physics’s older brother gonna be looking for this guy.
Newton? Never heard of him.
I am not well versed in modern electric bikes. Do they offer regenerative braking yet?
Yes but they do not offer regenerative… Accelerating
My e-bike dosen’t have it and it’s sounds pretty complex to add efficiently on a bike. It’s just take like 5 hours to charge in a normal output. And every corporate building have outputs for e-bike so I can charge while working.
I mean… regenerative braking is a thing.
My hybrid Prius C had this, and yes, you actually can build up some useful amount of charge from just rolling down a decently large or long hill, and you can also run the car on pure EV mode, though you’re probably not gonna top 20 mph on a flat road.
Obviously this does not create an over unity situation or perpetual motion machine, but, if this guy can figure out a way to put a regenerative braking type device onto an E-Bike, or maybe motorcycle/moped, in a way that isn’t stupid expensive…
That could increase overall range, and I think it would be neat.
Though I… don’t really know why you wouldn’t just use one battery for the whole system, just have a modulation/regulation system for it.
