Does it charge whist pedaling

[IR772]

If 745 watts is about 1 horse power then 500 watts would be more than a slight drag as horses are big.

"The net power from the electrical system is greater than zero."

Are you saying that the rider is producing more electricity than he is using, and cycling along at the same time.

 

[Danidl]

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.

Hey d8veh, you winding us up? A dynamo will be a load of say 6w , the bottle type tyre friction ones more and hub ones less. The assumption behind this design is that work done by the motor on front wheel in propelling the bike generates free energy which the backwheel absorbs and charges the second battery. On the basis of your excellent calculation s it takes in the order of 150w to propel the bike at normal speed. The cyclist can provide all this or the motor can assist. If the generator seeks to charge at 100w and even with 100% efficiency, then the cyclist plus motor must generate 250w. The backwheel will exhibit a load or mechanical resistance of 100w.

 

[Gubbins]

Tonight I have rocketed down a 900 ft or so steep hill at in excess of 40mph and I wonder how much energy was used to stop me at the bottom...
If it was possible to harness this then I assume we would see it on the high end bikes..

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[Danidl]

Tonight I have rocketed down a 900 ft or so steep hill at in excess of 40mph and I wonder how much energy was used to stop me at the bottom...
If it was possible to harness this then I assume we would see it on the high end bikes..

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Hi you don't need to wonder. Your kinetic energy is 0.5(your weight +bike weight) x speed xspeed . If using kgms for weight and metres /second for speed then your energy is joules . I f you want to convert that to watt hrs it is joules / 3600.

A number of the us sites refer to regenerative braking and basically conclude that it is not economically effective on a bike but very effective on a car which is essentially 100 times more massive. The additional weight of controls needed would be better spent on a larger battery.

 

[Gubbins]

So really one needs a Tesco battery system.....
Every little helps!!

 

[Deleted member 4366]

If 745 watts is about 1 horse power then 500 watts would be more than a slight drag as horses are big.

"The net power from the electrical system is greater than zero."

Are you saying that the rider is producing more electricity than he is using, and cycling along at the same time.

Its a 500w generator, but it's only generating about 100w. Drag is proportional to the generated power.

The rider is using more energy than he himself is producing. That's why his batteries are down after 130km.

Let's say that he's pedalling at about 100w, the motor is producing 200w, the generator is absorbing 150w and generating 100 watts. That means his net motive power is 150watts and he's using battery at the rate of 50w. His battery is about 300wh, which would last him 6 hours and take him 130km at 21.6km/h.

 

[Deleted member 4366]

Hey d8veh, you winding us up? A dynamo will be a load of say 6w , the bottle type tyre friction ones more and hub ones less.

No it's not a wind up. Sticking a dynamo on an electric bike is one of the most ludicrous things I've heard, but there's plenty of them. I gasp in incredulity every time I see one.

 

[D8ve]

Its a 500w generator, but it's only generating about 100w. Drag is proportional to the generated power.

The rider is using more energy than he himself is producing. That's why his batteries are down after 130km.

Let's say that he's pedalling at about 100w, the motor is producing 200w, the generator is absorbing 150w and generating 100 watts. That means his net motive power is 150watts and he's using battery at the rate of 50w. His battery is about 300wh, which would last him 6 hours and take him 130km at 21.6km/h.

He is pulling 200 watts from the battery and returning 100 watts in your scheme D8veh so the battery will only last 3 hours.
You could remove the generator cycle at 100 watts plus 50 watts from motor, 300 watt hour battery lasts 6 hours. The bike is lighter, and you don't waste 50 watts in the regen cycle. Much easier to hold 21 kph too.

 

[anotherkiwi]

I am waiting for the version where he has a Li-ion battery which wants 42 V at 2 Amps at the charging port (about 100W if you factor in the losses) and a turbo button which lets you switch from a 250 W motor with 500 W generator to a 500 W motor with a 250 W generator. And Elon Musk mode: a 250 W motor plus a 500 W motor which gives a spurt of power which burns through battery capacity in about 45 seconds leaving dark burn marks on Mars.

 

[Deleted member 4366]

Or remove the generator cycle at 100 watts plus 50 watts from motor, 300 watt hour battery lasts 6 hours. The bike is lighter, and you don't waste 50 watts in the regen cycle. Much easier to hold 21 kph too.

Don't spoil his invention. It's brilliant - must have dreamt about it for ages before finally getting the wherewithal to construct it.

A bit like the model boat I built when I was 11. It had a big scoop/nozzle on it. When I pushed it forward, the scoop would compress the air and make it come rushing out the nozzle like a jet to push it forward and cause the scoop to compress more air.

 

[D8ve]

Don't spoil his invention. It's brilliant - must have dreamt about it for ages before finally getting the wherewithal to construct it.

A bit like the model boat I built when I was 11. It had a big scoop/nozzle on it. When I pushed it forward, the scoop would compress the air and make it come rushing out the nozzle like a jet to push it forward and cause the scoop to compress more air.

But that's the trick they use in jet engines isn't it?
Ps see my corrected calculation on your figures above.

 

[soundwave]

light waves

 

[mike killay]

light waves

Who is light, and who is he waving to?

 

[Danidl]

No it's not a wind up. Sticking a dynamo on an electric bike is one of the most ludicrous things I've heard, but there's plenty of them. I gasp in incredulity every time I see one.

Yes I can see the irony in it but there is another consideration. Security. & Safety.

In the old days of expensive ever ready batteries and lamps and vigilant police, the built in dynamo on the more expensive bikes gave a reassurance that there would be lighting. I would have put a bottle dynamo on every bike I owned, just so I would not be caught out.
With a large battery pack, wiring in a lamp from the pack seems a given, however as the bulbs or leds operate at around 3v and the pack is at 36v , either a DC to DC convertor or a wasteful dropper resistor is needed.

A hub dynamo is very much a set and forget option. , And while expensive it does not absorb much power probably 6w when operational and nothing when off.
Charging another two batterys particularly when they last a long time is more of a forget option
The Bosch system presumably includes a DC DC convertor because it can charge the display panel and also run lights. However on the Raleigh's they have opted to include hub dynamos with some energy storage instead so that the lights remain on for a few minutes after the wheel stops.

 

[flecc]

He is pulling 200 watts from the battery and returning 100 watts in your scheme D8veh so the battery will only last 3 hours.

Even less. For the quoted 200 watts output of the motor, it's drawing more like 280 watts from the battery, since the motor is not 100% efficient.
.

 

[Deleted member 4366]

Even less. For the quoted 200 watts output of the motor, it's drawing more like 280 watts from the battery, since the motor is not 100% efficient.
.

Those figures were not supposed to be real. They were only a rough example of how it might work. You can adjust all the figures until it works out.

 

[D8ve]

It would never work it's a perpetual motion machine.
But your not daft your pulling legs.

 

[flecc]

You can adjust all the figures until it works out.

The authors of this contraption certainly did that!

- - - and didn't know when to stop!
.
.

 

[Deleted member 4366]

It's a shame he didn't try it without the generator. It would have gone a lot further. It's not a perpetual motion machine and was never claimed to be one. What it is is a normal electric bike with a device to slow down the rate at which you can use the power that wastes some power during that process.

He could have achieved the same by shaving or crimping the shunt in his controller, which would increase his system efficiency and be a lot cheaper and simpler

 

[Gubbins]

S0 it's not even theoretically possible then?

Infinite, free energy? New loophole in Laws of Thermodynamics found http://dailym.ai/2fHAosc via http://dailym.ai/android

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