E-Bike Concept

[JPWroble]

The Idea

 

The idea came from this YouTube video. As good as I believe German engineering to be, I really don't want to pay 40k for a bicycle/motorcycle. I've wanted to make my own E-Bike but the batteries take forever to charge and making a weed eater motor cycle is out of the question

 

The visual:

 

 

Gear Box

 

Gears A1, B1, C1 & D1 are all 7"

Gears A2, B2, C2, D2 & D3 are all 3"

A1 is the bike peddle and crank

D2 & D3 are alternators or converted electric generators

A1 and A2 are connected by chain

A2 and B1 are attached directly

 

B1 and B2 are connected by chain

B2 and C1 are attached directly

 

C1 and C2 are connected by chain

C2 and D1 are attached directly

D1 and D2 are connected by chain

D1 and D3 are connected by chain

 

Info:

 

Two D1's exist so D2 and D3 can be rotated at the same RPMs

Due to the gear ratios the ending calculation would be A1 to D2 & D3 would be 1:~150. One turn of A1 would be about 150 turns of D2 and D3 which means 2000 RPMs would be very easy to achieve for one alternator so using two alternators just add more voltage.

 

Question 1:

 

If D2 & D3 take a certain amount of energy to be turn how would you calculate how much energy I would need to push on the cranks to move it.

 

Question 2:

 

What type of alternator to tire hub connection would be possible? As is (using a converter for the electricity) would I be able to make the hub spin faster due to the amount of more energy is created thus meaning, the more I peddle the faster I go. So in a sense peddle assisted e-bike hub. OR, would I have to charge the batteries as I peddle and use a throttle.

 

Question 3:

 

How do you pick out a alternator that will do the job a need to have done?

 

 

PS: Check the Image for a better idea of the gear box

 

Edited October 6, 2012 by JPWroble

[JPWroble]

Is is possible to make a bike into a strong enough moving generator to power a battery which powers a hub?

 

1. The crank you turn the gear labeled 1
2. Then going through the gear box using ratios, gear 2 would be spinning very fast
3. Because gear 2 is spinning fast it will spin gear 3 fast enough to produce power
4. Since gear 3 is the alternator which is producing power it will charge the battery
5. The battery will power the hub
6. OR the battery can be left behind and the alternator connects directly to the hub.

 

 

Hopefully the "moving generator" will charge faster then the energy is used.

 

Can anyone find issues with the idea/concept or things that become problematic like laws of physics?

I would also like to see if it would be possible to make a set-up where one persons power is enough for two people to ride on the E-Bike.

(250-300lbs not including components)

 

And yes I know this is a basic setup and the I would have to add in inverters and whatnot.

Edited October 6, 2012 by JPWroble

[InigoMontoya]

Hopefully the "moving generator" will charge faster then the energy is used.

 

Can anyone find issues with the idea/concept or things that become problematic like laws of physics?

Yes. The "moving generator" charging faster than the energy used is otherwise known as a "perpetual motion machine" and violates the 2nd Law of Thermodynamics.

 

In other words, it won't work the way you think it will.

[JPWroble]

See I thought that would be the case but I still think it will work. I'm not using the bike hub power or my momentum to charge the battery, I'm using my energy only to charge the battery. There is no connection from the sprocket of the wheel/hub to the gear box or alternator. And when i said the alternator connects directly to the bike a meant by wire to power it, no by chain,

 

 

So technically wouldn't it be the case that as long as I peddle fast enough to charge the battery faster then the hub consumes the energy, be possible?

 

And perpetual motion is something that goes forever and well, Im gonna die eventually. I can't peddle the bike all night and day.

Edited October 7, 2012 by JPWroble

[InigoMontoya]

See I thought that would be the case but I still think it will work. I'm not using the bike hub power or my momentum to charge the battery, I'm using my energy only to charge the battery. There is no connection from the sprocket of the wheel/hub to the gear box or alternator. And when i said the alternator connects directly to the bike a meant by wire to power it, no by chain,

 

 

So technically wouldn't it be the case that as long as I peddle fast enough to charge the battery faster then the hub consumes the energy, be possible?

 

And perpetual motion is something that goes forever and well, Im gonna die eventually. I can't peddle the bike all night and day.

 

Read my lips: It won't work.

 

It would actually be much more efficient for you to simply power the bike with a chain connected to the pedals and the hub (ie, like every other bike on Earth).

 

Energy is energy. If you put 1000 Joules of energy into the pedals, the absolute maximum amount of energy you can ever get out of your system - no matter how it's arranged - is 1000 Joules. In reality, you'll always get less.

 

So... you put 10000 Joules into the pedals. Using a traditional bike, you'll get on the order of 900 Joules at the bike's hub (the traditional chain/sprocket system is about 90% efficient). But what would you get out of your generator system?

 

From the pedals to the gearbox, you'd get about 900 Joules (chain/sprocket system, just like to the wheels). From the gearbox to the generator you'd get about 810 Joules (I'm being nice; your stated gearbox design is grossly inefficient but I'm giving you the benefit of a doubt and giving you the same 90% as a simple chain/sprocket system). From the generator to the battery, I'll again be nice and give you 95% efficiency (it will really be less) which then allows you to store 770 Joules in your battery. From the battery to the motor in the bike's hub, we'll again give you 95%.... Giving you 731 Joules.

 

You lost 169 Joules because you jumped through all sorts of crazy hoops to avoid simply pedaling your bike. And again, I'm being very nice with my numbers. The reality will probably be much worse.

 

It. Won't. Work.

 

At least, not the way you think it will. Your bike will move and all that... But it will suck.

Edited October 8, 2012 by InigoMontoya

[JPWroble]

Read my lips: It won't work.

 

It would actually be much more efficient for you to simply power the bike with a chain connected to the pedals and the hub (ie, like every other bike on Earth).

 

Energy is energy. If you put 1000 Joules of energy into the pedals, the absolute maximum amount of energy you can ever get out of your system - no matter how it's arranged - is 1000 Joules. In reality, you'll always get less.

 

So... you put 10000 Joules into the pedals. Using a traditional bike, you'll get on the order of 900 Joules at the bike's hub (the traditional chain/sprocket system is about 90% efficient). But what would you get out of your generator system?

 

From the pedals to the gearbox, you'd get about 900 Joules (chain/sprocket system, just like to the wheels). From the gearbox to the generator you'd get about 810 Joules (I'm being nice; your stated gearbox design is grossly inefficient but I'm giving you the benefit of a doubt and giving you the same 90% as a simple chain/sprocket system). From the generator to the battery, I'll again be nice and give you 95% efficiency (it will really be less) which then allows you to store 770 Joules in your battery. From the battery to the motor in the bike's hub, we'll again give you 95%.... Giving you 731 Joules.

 

You lost 169 Joules because you jumped through all sorts of crazy hoops to avoid simply pedaling your bike. And again, I'm being very nice with my numbers. The reality will probably be much worse.

 

It. Won't. Work.

 

At least, not the way you think it will. Your bike will move and all that... But it will suck.

 

So from this I might as well just make a regular E-Bike.

 

Now, would there be any point into making a secondary energy source that uses up the left over momentum, energy from down hill or excess peddling to put some energy back into the battery? The idea being not perpetual motion, but longer lasting?

 

Lastly, which area of physics or engineering would be best to look at to get a better understanding of your explanation? Just looking to learn and experiment.

 

Thanks for being patient and answering my questions and giving a dose of reality

 

PS: Sorry if I come off pompous and or ignorant to the certain knowledge that would point this stuff out to me in the first place. For the questions I've posted, its hard to find the information and answers I'm looking for.

Edited October 8, 2012 by JPWroble

[InigoMontoya]

So from this I might as well just make a regular E-Bike.

Yup.

 

Now, would there be any point into making a secondary energy source that uses up the left over momentum, energy from down hill or excess peddling to put some energy back into the battery? The idea being not perpetual motion, but longer lasting?

 

In theory, a bike with regenerative braking (what you're talking about) could work, but I don't know that it would be worth it. Bikes are dominated by wind resistance and regenerative braking won't help that at all.

 

Lastly, which area of physics or engineering would be best to look at to get a better understanding of your explanation? Just looking to learn and experiment.

Plain ol' Newtonian Physics and Thermodynamics.

 

The Physics will give you the foundation to understand the Thermodynamics. The Thermodynamics are at the core of discussions such as this one.

 

Note: Thermodynamics aren't just the study of heat flow. They're the study of energy flow.

Edited October 8, 2012 by InigoMontoya

[Dekan]

JPWroble's OP raises a point that has always slightly puzzled me. Why should bicycles be better than walking?

 

What I mean is this - suppose you make a journey from A to B. The distance is, say 20 miles. And you have to cover the distance by walking. It will probably take you at least 5 or 6 hours. And you'll arrive at your destination feeling quite leg-worn and tired.

 

Whereas if you have a bicycle, you can get on it and ride the distance in an hour or so. And dismount from your bike, with much less sense of fatigue.

I wonder why that should be so. Because looking at it logically, there are two situations:

 

1. When you walk the 20 miles from A to B - you only have to move the mass of your own body

 

2. But when you use the the bike - you have to move the mass of the bike as well.

 

Just to make point 2 clearer - suppose you don't actually sit on the bike. Just walk alongside it, wheeling it along with you. Holding the bike's handlebars in your hands, and pushing it along. Won't this effort of pushing, make the bike an added burden - and make you arrive feeling even more tired?

 

So why does sitting on the bike make things better?

Edited October 8, 2012 by Dekan

[InigoMontoya]

So why does sitting on the bike make things better?

 

In a word: Gravity.

 

To walk, you must stabilize your entire body against the effects of gravity.

 

To sit, you only have to stabilize your upper body. Your lower body no longer fights gravity. That means you aren't working as hard.

[Dekan]

In a word: Gravity.

 

To walk, you must stabilize your entire body against the effects of gravity.

 

To sit, you only have to stabilize your upper body. Your lower body no longer fights gravity. That means you aren't working as hard.

 

But when you're on the bike, you've got the added weight of a metal contraption under your lower body. So your body has to fight against gravity to stabilize the extra weight. Otherwise it would make you fall over. That must make you work harder surely?

[InigoMontoya]

But when you're on the bike, you've got the added weight of a metal contraption under your lower body. So your body has to fight against gravity to stabilize the extra weight. Otherwise it would make you fall over. That must make you work harder surely?

Do the wheels collapse under 1 G acceleration? No.

 

Do your legs collapse under 1 G accleration? yes.

 

When I speak of stabilization, I'm not talking about balance. I'm talking about structural integrity.

[ACUV]

Dekan,

 

I have cycled up a few hills and here are a few conclusions. If you try to maintain the same speed when you cycle compared to when you walk, it will be easier, in the right gear. I can cycle for 10 minutes up a hill at a decent speed and when I try to walk the same hill at the same speed I have to stop every 3/4 minutes to have a rest. Practically, it is proven to me even if the physics theory is a little unclear.