dynamo on a bike

General Discussion about electric bicycles.
dustNbone   10 kW

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Re: dynamo on a bike

Post by dustNbone » Aug 31 2019 9:48pm

From the Vello page:

"You can ride up to 15 miles per hour (25 km/hour) for unlimited mileage in "self-charging mode", or in "turbo mode" up to 18-30 miles (30-50 km) on a full charge without any effort."

You can ride 15mph for unlimited mileage on pretty much any bicycle in the world. That's kind of what they do.

There's nothing special here, aside from some slick marketing. I can't believe they get to take people's money for this.

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wturber   10 MW

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Re: dynamo on a bike

Post by wturber » Aug 31 2019 11:13pm

WALLEY wrote:
Aug 31 2019 4:26pm
wow that mando footloose looks promising though
In what way is it promising?
"Commuter - DC Booster"
Iron Horse 3.0 hardtail - 48V / 1000W / 470rpm generic Chinese DD Hub motor (ebay)
8 x 36v 4.3ah 10s 2P battery packs - 1500W 30A DC Boost Converter delivers 54v and about 1000 watts peak
53T/42T Sakae Road cranks - 30mph+ on flats
viewtopic.php?f=2&t=90369

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Re: dynamo on a bike

Post by docw009 » Sep 01 2019 3:37pm

WALLEY wrote:
Aug 31 2019 4:26pm
wow that mando footloose looks promising though
From a review.
"With the unnatural feel and noise of an outdated piece of exercise machinery, the limited power and speed of a European specced ebike and a price tag befitting a cheap used car the Mando Footloose is a curiosity. I really appreciate the time and energy that Mando has put into producing something truly unique, people at Interbike couldn’t stop talking about the Footloose, but not everything they had to say was positive and I agree that this first iteration definitely has room for improvement. "

https://electricbikereview.com/mando/footloose/

flat tire   1 MW

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Re: dynamo on a bike

Post by flat tire » Sep 01 2019 4:30pm

The mando footloose is retarded as hell.

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MadRhino   100 GW

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Re: dynamo on a bike

Post by MadRhino » Sep 02 2019 4:36pm

flat tire wrote:
Sep 01 2019 4:30pm
The mando footloose is retarded as hell.
Retarded In design or production?

Well, both I guess, the latter being the consequence of the first.
Make it fool-proof, and I will make a better fool.

baphensley   1 µW

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Re: dynamo on a bike

Post by baphensley » Mar 12 2020 12:49am

All ... Noob here; apologies in advance for breech of protocol.

OP ... If I read your post correctly, you are not actually interested anything close to perpetual motion, but if it's feasible to build a chainless all-electric bike. A search of Wikipedia for "series hybrid bicycle" will turn up an article that I believe confirms your suspicion, as does the link below. Poking around there will point out some advantages of an all-electric drive train and lead you to research studies proving feasibility with prototypes. I'm afraid I couldn't find it with a quick look, but last year I saw a YouTube video with someone using the design for a homebuilt bike or trike. Happy hunting.



Series Hybrid Cycles by Andreas Fuchs - Google Sites

https://sites.google.com/site/serieshybridbikes

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MadRhino   100 GW

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Re: dynamo on a bike

Post by MadRhino » Mar 12 2020 8:39pm

baphensley wrote:
Mar 12 2020 12:49am
All ... Noob here; apologies in advance for breech of protocol.

OP ... If I read your post correctly, you are not actually interested anything close to perpetual motion, but if it's feasible to build a chainless all-electric bike. A search of Wikipedia for "series hybrid bicycle" will turn up an article that I believe confirms your suspicion, as does the link below. Poking around there will point out some advantages of an all-electric drive train and lead you to research studies proving feasibility with prototypes. I'm afraid I couldn't find it with a quick look, but last year I saw a YouTube video with someone using the design for a homebuilt bike or trike. Happy hunting.



Series Hybrid Cycles by Andreas Fuchs - Google Sites

https://sites.google.com/site/serieshybridbikes
This had been done some 10 years ago by an ES member who had built a velomobile. Still, if pedal input is important, better make it efficient. Every energy conversion does result in a loss.
Make it fool-proof, and I will make a better fool.

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wturber   10 MW

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Re: dynamo on a bike

Post by wturber » Mar 13 2020 10:08pm

MadRhino wrote:
Mar 12 2020 8:39pm


This had been done some 10 years ago by an ES member who had built a velomobile. Still, if pedal input is important, better make it efficient. Every energy conversion does result in a loss.
You may be referring to this design:

http://www.electrom.ca/

But the choice to have a dynamo drive was certainly not for efficiency. It is my interpretation that the main reasons are to allow the Electrom to legally qualify as a bicycle and to provide a means to get some exercise while riding while increasing range.

Ooops. Forgot. This is a hybrid dynamo drive. It provides direct chain drive at lower speeds and is full dynamo only after the bike hits 6mph.
"Commuter - DC Booster"
Iron Horse 3.0 hardtail - 48V / 1000W / 470rpm generic Chinese DD Hub motor (ebay)
8 x 36v 4.3ah 10s 2P battery packs - 1500W 30A DC Boost Converter delivers 54v and about 1000 watts peak
53T/42T Sakae Road cranks - 30mph+ on flats
viewtopic.php?f=2&t=90369

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MadRhino   100 GW

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Re: dynamo on a bike

Post by MadRhino » Mar 13 2020 10:17pm

I was not referring to this one, but that is some example. I can’t remember the name. It was a long, full faired low rider velomobile with big prismatic lifepo4 batteries. Some guy in east EU I believe.
Make it fool-proof, and I will make a better fool.

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Re: dynamo on a bike

Post by amberwolf » Mar 13 2020 11:02pm

there was a trike by lowracer, but all his pics and vids are long gone. :(
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Krymz   1 µW

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Re: dynamo on a bike

Post by Krymz » Apr 13 2020 11:40am

What about a dynamo that charges your empty battery while you use your spare (and vice versa)?

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Re: dynamo on a bike

Post by miro13car » Apr 13 2020 12:56pm

"I just wished I had more Ah...."
Just get bigger battery with more Ahours instead of all this complexity of generator/alternator.
as they told you no alternator or generator is 100% efficient , why all this trouble?
Eplus, Bionx

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amberwolf   100 GW

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Re: dynamo on a bike

Post by amberwolf » Apr 14 2020 12:17am

Krymz wrote:
Apr 13 2020 11:40am
What about a dynamo that charges your empty battery while you use your spare (and vice versa)?
if you mean a dynamo in the wheel, then it's just going to drain the spare faster than if you didn't do this, so you get less range than just riding normally--there are always losses in a system. most likely you would have up to 50% power loss in all the conversion stages, so you would get only half the range by doing this than if you had no dynamo and just rode normally.

even if you had zero losses (which will never happen), you still would only have exactly the same range you had without the dynamo, making it pointless to do.

you would require an external source of energy, not connected to the bike's motion, to get extra energy to recharge a battery that would let you then use that energy to keep powering the bike. (like solar panels, or a gasoline generator)

it's simpler, cheaper, smaller, and lighter, just to get a bigger capacity battery.

Genesis Andy   100 µW

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Re: dynamo on a bike

Post by Genesis Andy » Apr 17 2020 11:40am

I have a dynamo on our ebike. Its for lights only. It would never have the capability to charge the battery

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Stealth_Chopper   100 W

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Dynamo on a bike: warming the battery?

Post by Stealth_Chopper » Apr 17 2020 12:13pm

Hi,
I'm glad this topic remains in question.
Yes, energy is conserved but on turbofan engines compressed fan air is used to cool turbine cases yielding performance gain

Since our batteries have measurably better performance with "warmth" versus frozen or in the process of freezing :

Why not DC warming pads run by a generator?
Mike

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Re: dynamo on a bike

Post by amberwolf » Apr 17 2020 9:49pm

If the pads run on the same voltage as the battery itself (you can get versions that do if the ones you have don't, or you can put low voltage ones in series to do so), then it will be more efficient to directly run the pads off the battery itself.

That way you don't have the losses in the conversion from battery into controller into motor thru drivetrain thru tire onto road back thru other tire and then thru dynamo before going to the heaters.

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MadRhino   100 GW

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Re: dynamo on a bike

Post by MadRhino » Apr 17 2020 10:07pm

amberwolf wrote:
Apr 17 2020 9:49pm
If the pads run on the same voltage as the battery itself (you can get versions that do if the ones you have don't, or you can put low voltage ones in series to do so), then it will be more efficient to directly run the pads off the battery itself.

That way you don't have the losses in the conversion from battery into controller into motor thru drivetrain thru tire onto road back thru other tire and then thru dynamo before going to the heaters.
This basic concept of energy physics, seem impossible to admit by some. No matter how you explain, those will always come with another twist trying to escape logic. :roll:
Make it fool-proof, and I will make a better fool.

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Stealth_Chopper   100 W

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Re: dynamo on a bike

Post by Stealth_Chopper » Apr 20 2020 9:21pm

conservation of energy ;
A simple equation ?
Not
MadRhino wrote:
Apr 17 2020 10:07pm
amberwolf wrote:
Apr 17 2020 9:49pm
If the pads run on the same voltage as the battery itself (you can get versions that do if the ones you have don't, or you can put low voltage ones in series to do so), then it will be more efficient to directly run the pads off the battery itself.

That way you don't have the losses in the conversion from battery into controller into motor thru drivetrain thru tire onto road back thru other tire and then thru dynamo before going to the heaters.
This basic concept of energy physics, seem impossible to admit by some. No matter how you explain, those will always come with another twist trying to escape logic. :roll:
Last edited by Stealth_Chopper on Apr 22 2020 9:33pm, edited 1 time in total.

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MadRhino   100 GW

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Re: dynamo on a bike

Post by MadRhino » Apr 20 2020 10:27pm

Stealth_Chopper wrote:
Apr 20 2020 9:21pm
Really , how did we miss that conservation of energy thing ;
How simple and so basic you ignore the battery chemistry of warm batteries versus frozen that I refered to.
And the small front hub generator connected to warming pads requiring negligible drag while producing juice.
Your Snappy answers , O meh :lol:
MadRhino wrote:
Apr 17 2020 10:07pm
amberwolf wrote:
Apr 17 2020 9:49pm
If the pads run on the same voltage as the battery itself (you can get versions that do if the ones you have don't, or you can put low voltage ones in series to do so), then it will be more efficient to directly run the pads off the battery itself.

That way you don't have the losses in the conversion from battery into controller into motor thru drivetrain thru tire onto road back thru other tire and then thru dynamo before going to the heaters.
This basic concept of energy physics, seem impossible to admit by some. No matter how you explain, those will always come with another twist trying to escape logic. :roll:
Last chance I try giving a short answer to this, after which I just give up and leave you with the illusions that you seem comfortable with.

The ‘little drag’ of your front motor, is energy sucked from the battery anyway, and considerably more of it that it does produce in return. ´nuff said
Make it fool-proof, and I will make a better fool.

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Re: dynamo on a bike

Post by john61ct » Apr 21 2020 9:01pm

The real gist of OP's fantastic misunderstanding
amberwolf wrote:you require an external source of energy, not connected to the bike's motion, to get extra energy to recharge a battery that would let you then use that energy to keep powering the bike. (like solar panels, or a gasoline generator)
I mean, how could this not be obvious?

Like RVers asking "why not rig a wind generator for when I'm driving down the highway?"

If you really don't understand these fundamentals, you'll just need to take our word for it

such "perpetual motion" ideas are for the birds.


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Re: dynamo on a bike

Post by MikeyMK » Jul 28 2021 10:02pm

Okay, thread bump as i want to do this.

I hear everyone's reasons why it's pointless, and i get that. I have two cranks on my 72v child-back e-tandem and with the rear crank a 2:1 final drive the gearing allows a comfortable cadence at 60mph. But my tandem is not the subject.

One reason for a crank generator could be consistency. Direct pedaling at vastly varying speeds means vastly varying cadence and efforts, and therefore lots of gears and gear changes. The beauty of e-bikes is their ability to make a ride linear. A consistent push against a generator could be advantageous.

At least it would be on my recumbent tadpole. With the crank and rear cassette over 5ft apart, and the seat intruding the direct line between them, a chain is a hindrance. Hundreds of links, some 12ft altogether, various relay sprockets (or plastic water pipes) ensure one's pedaling losses are already considerable - and that's when the chain doesn't come off, and drag along the floor...

Far better would be to take the chain out of the equation altogether. This bike runs 48v and for that i should have no problem generating several amps. It wouldn't be enough to keep the batteries charged, but it'd act as a range extender.

Does anyone know the best equipment for me to use for this set-up, or can see any major holes in the plan?

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Re: dynamo on a bike

Post by Chalo » Jul 29 2021 1:49am

Why don't you pedal a pneumatic pump to pressurize a tank, then use an air motor to propel your bike? That would at least give your bike the opportunity to produce the occasional fart sound.
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Re: dynamo on a bike

Post by john61ct » Jul 29 2021 2:22am

Arms flailing to power a big fan like those Florida boats

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Monte   10 mW

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Re: dynamo on a bike

Post by Monte » Jul 29 2021 6:56am

WALLEY wrote:
Aug 30 2019 6:56am
SO THERES no way of getting the power enough to power a motor simple by peddling a generator or dynamo.

seems I remember a guy out of Germany who had a bike that could 50 miles a hour by peddling I haven't found that vid in a while now I guess 7 years but he had a nice concept he was trying get a patent for it. he probably sold it . now its buried

guess getting a bigger battery is the only way
Changing your front chainring to a larger one is the easiest option as stated above.

This German guy pedaling at 50 mph was likely rocking one of these:

http://www.schlumpfdrive.com/index.php/ ... drive.html

It's a planetary gearbox integrated into the chainring which allows a 1:1 or 1:2,5 ratio allowing the user to e.g. pedal at 20 or 50 mph depending on which gear is chosen up front.


People have also built systems like you mention with no mechanical drivetrain from pedals to rear wheel using a generator like this one:
https://www.electrom.ca/

Obviously you lose some of your human input with the inefficiency of the conversion.

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Re: dynamo on a bike

Post by john61ct » Jul 29 2021 11:42am


Monte wrote: This German guy pedaling at 50 mph was likely rocking one of these:

http://www.schlumpfdrive.com/index.php/ ... drive.html

It's a planetary gearbox integrated into the chainring which allows a 1:1 or 1:2,5 ratio allowing the user to e.g. pedal at 20 or 50 mph depending on which gear is chosen up front.
1.65 overdrive version too


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