Does it charge whist pedaling

[Gubbins]

Apologies if someone else has offered this but I have looked first..
What's so new about this... is it a joke?
Not an engineer or anything but diminishing return an all that..
http://m.carandbike.com/reviews/global-renergy-self-charging-electric-bicycle-prototype-review-1586657

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[anotherkiwi]

OMG...

I don't understand why they didn't just use a 1 kW direct drive "generator" in the rear. I mean while you are dragging around all that extra weight you might as well get real leg muscles with an extra 4 kg or so...

 

[Alan Quay]

Apologies if someone else has offered this but I have looked first..
What's so new about this... is it a joke?
Not an engineer or anything but diminishing return an all that..
http://m.carandbike.com/reviews/global-renergy-self-charging-electric-bicycle-prototype-review-1586657

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It's utter nonsense I'm afraid.

'low friction generator' is the problem here. Assumining the generator is 100% efficient then it can only generate as much energy as the front motor produces.

Since neither the motor or generator are anywhere near 100% efficient, then transferring energy from one to the other will create a net loss. Probably around 60% loss on a good day.

It's basic physics, and it will never change while we remain in this universe. It's probably the same in all other universes, but I have no practical experience of them.

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[IR772]

"this bicycle could technically go on and on forever making its own electric power" , not with Earth technology it won't.

What they skip over is the truth, of diminishing returns and inefficiency in every device.

Just claptrap looking for some gullible backers. Plus it looks like a dog.

" in Physics is that energy is constant and can nether be created nor destroyed"

No but it can change its form.

 

[Gubbins]

Aww!!
And I was going to send a few Rupees that I have laying around..
So, the next time I am asked if it charges when pedaling I can honestly say.. Yes , But only in India!!

 

[Danidl]

Apologies if someone else has offered this but I have looked first..
What's so new about this... is it a joke?
Not an engineer or anything but diminishing return an all that..
http://m.carandbike.com/reviews/global-renergy-self-charging-electric-bicycle-prototype-review-1586657

Sent from my SM-G920F using Tapatalk[/QUOTE

Hi I do not think this is a wind up , just the results of woolly thinking. The reporter seems to think so also but had a story to file.
From what I can see is 4 of 12v batteries each probably 20amp hr wired in series and parallel giving 24v at 20amphr or 480whr. The motor is stated as a 250w and presumably 24v working. and the author states there is another bank below that.
Assuming that all batteries are initially charged a range of 130km is not unreasonable.
What is unlikely is that the generator in the backwheel will actually charge the battery pack. Unless it is one of the older brushed motors , which is likely it will not generate usuable current , without extensive electronics. Even if it is then it needs to create a voltage in excess of the 24v and as the wheels are matched in size I would have difficulty in seeing where the voltage would come from. Voltage in a generator is dependent on rotational speed.
Even were it to generate a voltage then the fundamental physics would come into play and it becomes an expensive way of generating heat.
It looks to me like a student project carried through with diligence and good production values but without adequate consideration of fundamentals.
I would give the student a C degrade and his supervisor a talking to.

 

[mike killay]

When they say,
'If you push it to its limits it can do 130kms'
Do they mean that literally, i.e....get off and push?

 

[Alan Quay]

That's not correct.

There are 4 x 12v/10ah batteries. SLA will only give about 50% of it capacity at the sort of C rate required for a pedelec, so this machine has about 240wh of usable capacity. It will be extremely heavy, having two motors in addition to the batteries.

I'd be surprised if it were able to cover 20 miles of normal British terrain, less if very hilly.

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[IR772]

When they say,
'If you push it to its limits it can do 130kms'
Do they mean that literally, i.e....get off and push?

I think the bike can do what ever you want if you are promising money.

 

[Alan Quay]

I assume this is a school project, of which the the CDT teacher should be proud. Unfortunately the physics teacher needs to be taken outside and beaten like a ginger step child.

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[Danidl]

That's not correct.

There are 4 x 12v/10ah batteries. SLA will only give about 50% of it capacity at the sort of C rate required for a pedelec, so this machine has about 240wh of usable capacity. It will be extremely heavy, having two motors in addition to the batteries.

I'd be surprised if it were able to cover 20 miles of normal British terrain, less if very hilly.

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Well we are guessing as to the actual size of these SLA batteries. I was giving the benefit of the doubt that they would be up to 20 Ahr. But the author did refer to another bank of batteries. . You may be correct in that the author referred to changing batteries at about 30 km.

 

[Gubbins]

In truth its looks like the sort of thing one might see weaving in and out of traffic with 2 riders and half a dozen kids hanging on the sides

 

[Fordulike]

When they say,
'If you push it to its limits it can do 130kms'
Do they mean that literally, i.e....get off and push?

No, I think they meant off a cliff

 

[Alan Quay]

Well we are guessing as to the actual size of these SLA batteries. I was giving the benefit of the doubt that they would be up to 20 Ahr. But the author did refer to another bank of batteries. . You may be correct in that the author referred to changing batteries at about 30 km.

I'm not guessing. I have experience with SLA's. Those are at the very most 14ah, but more likely 12ah. Just from the colour (and here I admit I'm making an educated guess) I'd say 10ah. They could be less than that if they are the wrong construction for the application, or old/miss-treated.

They are certainly not 20ah.

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[IR772]

Is trex is at this moment changing his new fat bike design after seeing this beauty.

 

[Wisper Bikes]

"While one of the two battery packs power the 250watt motor on the front wheels, the 500watt generator on the rear recharges the second battery pack. And theoretically, this could result in unlimited range."

Well I'm convinced! If we build a really big one we don't need any more oil, gas, coal or any of those pesky windmills. But we'd need a hell of a kick stand!

 

[Gubbins]

I think you are all taking the micky because you didn't think of it first.

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[Deleted member 4366]

Everything about that bike is true. I think you're all misunderstanding how it works. The range of 130 kms would be about right for an ebike with 4 x 10Ah 12v SLAs on flat ground, pedalled by a lightish fit Indian guy using assistance from the motor all the time..

 

[IR772]

Everything about that bike is true. I think you're all misunderstanding how it works. The range of 130 kms would be about right for an ebike with 4 x 10Ah 12v SLAs on flat ground, pedalled by a lightish fit Indian guy using assistance from the motor all the time..

What about the added resistance of having to drive the 500 watt generator while cycling.

I think the man would have to be light and fit as there looks to be at least 40kgs of battery and generator as added weight. ??

 

[Deleted member 4366]

Resistance added to what? The net power from the electrical system is greater than zero.

Don't forget that people on this forum have dynamos on their bikes for the lights. They also add resistance that's a dead loss. At least the resistance from that bike's generator puts energy back in the battery.