Check out how this guys talks about electric cars

morph999

100 kW
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Jan 20, 2009
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Listen to this guy for a few minutes talk about electric cars. It sucks.

http://fora.tv/2009/04/09/San_Francisco_Mayor_Gavin_Newsom_Cities_and_Time#SF_Mayor_Gavin_Newsom_Advocates_Innovative_Electric_Cars

If electric cars become more prevalent, you can bet they are going to increase the price of batteries. Can someone on here make a cheap way of producing electricity? For example, I'd like to get on an exercise bike and do 2 hrs of exercise and at the same time recharge my electric bike battery. I know it's possible already but the device I've seen is about $1500 or more. It'd be nice if it was about $500. I can just see that we will never be free unless we produce our own energy.
 
if you have a regenerative braking motor on the rear wheel of your E-Bike ... you can use the regenerative braking to recharge the batteries... during the winter and such... you put the bike on a bike stand and pedal away to recharge the batteries...

it will work just fine... I've seen it done many times ...

the problem is efficiency and in relative energy levels.

#1> The first and biggest hit is realative energy levels.

1A> You the rider.
If you as a rider can maybe pedal for ~100 Watts worth of energy for 1 hour straight ... you are in pretty good shape ... if you can pull off ~200 watts for ~1hour straight ... you are probably in excellent physical shape and could compete ... If you could pull off over ~300 watts for more than ~1 hour straight ... you are probably one the top bicyclists in the world.

1B>E-Bike ... many many E-bikes ... talk 24V or more and 10Ah or more worth of energy... this is over 240Watts of energy if put out in ~1 hour.... It isn't hard to find a E-Bike with 500Watts or even 1,000Watts.

#2> Efficiency:
You shouldn't have much trouble getting ~80% efficiency of energy conversion from mechanical wheel spinning ... to electrical energy ... above 90% is possible but more difficult... then of the electrical energy that comes out of the regenerative braking motor / generator ... how efficient is the control electronics that will feed it back to the battery?... you probably won't have much trouble getting up near 90% ... but it will get exponentially harder the higher you go... once the energy gets to the batteries ... how much energy of what you put in can you expect to get back out... this will vary greatly from battery type to battery type ... but generally ~80% back out of what you put in isn't too hard to get... above 90% can also be had with more work and cost...

so if you start with 100Watts of energy output for ~1 hours time ... you personally provided 100Wh of total energy... but... after even 80% regenerative conversion you are down to 80Wh ... after 90% control electronic you are down to 72Wh ... after 80% battery cycle efficiency ... you are down to ~57Wh ... back out through the 90% control electronics down to ~52Wh ... back out to the 80% motor down to 41Wh to the actual road.

With additional care and careful planning of parts and design and for addition $ ... you can do better ... or worse with a bad design... but in general ... you would have to provide twice as much pedal Wh of energy that you hope to get back latter on the road.

Given a ~100 Watt rider power output ... and even a modest 24V ~200Watt E-Bike system... you would have to exercise pedal... for about ~4 hours for every one hour you want the ~200Watt E-Bike system to run.

So yes you can do it... and if you want you could even power electronics at home with the energy you generated if you fill up the batteries... but it is allot of pedaling ...
 
The pedal powered sound systems I've seen and helped power require about four cyclists pedalling. You need a large body of volunteers in rotation to keep it running all day or night. Face it, after twenty minutes of pedalling to get nowhere you'd rather spend your energy dancing.
The generator units were converted motors stuck in stationary trainers. Friction drive so less than optimal. The first experiments had a few different set ups including a recumbent powered laptop. Recumbents are harder to adjust for the various sizes of meat based energy sources.

When Toronto had its blackout for a few days after the grid went down, I envisioned ebikers pedalling furiously all night so they could eride to work the next day. Riding a real bike would have been easier, more efficient and quicker. I guess they could have tapped a LED light off the bike too so they could read to keep from getting bored.
 
yeah I guess when I think about it, it makes no sense to recharge a battery to ride an e-bike if electricity became very expensive. It would make more sense to buy a $1000 - $3000 bike so I could go really fast just on pedal power. Anyone know how fast a 200lb man could go if he bought a really light fast bike for $1500. I don't even know how much I would need to spend. I guess if I was going to spend $3000, I might as well buy a velomobile. Could an average man sustain 20 mph on a lightweight bike built for racing?
 
For an experiment I pedalled a rear Xylite hub motor on rollers and could run an electric fan and a 75 watt lamp thru an inverter , the light flickered somewhat but I couldn't keep it going too long because there was back emf or something that caused it harder and harder to pedal. I could run a D.C. boom box playing CDs at a slow easy pace with no problem. Better idea for charging ebike batteries would be solar panels or a small wind turbine instead of pedalling. If i recall it was hard even to charge a 12 volt battery by pedalling because with moderate pedalling I only got 12+ volts, not enough for charging and to get to 14+ volts took too much effort.
 
morph999 said:
yeah I guess when I think about it, it makes no sense to recharge a battery to ride an e-bike if electricity became very expensive. It would make more sense to buy a $1000 - $3000 bike so I could go really fast just on pedal power. Anyone know how fast a 200lb man could go if he bought a really light fast bike for $1500. I don't even know how much I would need to spend. I guess if I was going to spend $3000, I might as well buy a velomobile. Could an average man sustain 20 mph on a lightweight bike built for racing?

A fit 200# cyclist might likely get dropped on climbs but get it back on descents and sprints. $3000 buys a lot of bike these days.
As a near "Clydesdale", opt for heavier hand built wheels rather than the low spoke botique wheels.
And then ride it until your ass falls off.
Pro roadies can average 40+ kmh for hundreds of miles. Track racers farther and faster.
As your fitness increases, and it does every time you ride, you'll find cycling more enjoyable.
Your half-mile rides now could be five miles within two months and twenty miles the next.
Barring physiological limitations, you could ride a century by fall.
 
morph999 said:
yeah I guess when I think about it, it makes no sense to recharge a battery to ride an e-bike if electricity became very expensive. It would make more sense to buy a $1000 - $3000 bike so I could go really fast just on pedal power. Anyone know how fast a 200lb man could go if he bought a really light fast bike for $1500. I don't even know how much I would need to spend. I guess if I was going to spend $3000, I might as well buy a velomobile. Could an average man sustain 20 mph on a lightweight bike built for racing?

It takes a few pennies worth of electricity to charge my battery. If electric rates would double it would cost a few extra pennies but that would be the least of my worries.

I'll say this to you again Morph, the bike doesn't make you fast, you make the bike fast. If you aren't in shape I don't care how much you spend on a fancy lightweight bike some old man who rides frequently is gonna pass you up no problem :p Still there's no substitute for youth but you have to ride...and ride some more to get in shape if you want to be able to average 20mph on a bike (w/o a motor).

-R
 
I have pretty high electric rates here, and my bike takes as much as 15 cents to go the 29 mile round trip. If electricity rates quadrupled, Photovoltaic panel energy would be cheaper even without tax incentives. Air conditioning would be very expensive, but my bike would still take less money for electricity than bus fare or a cup of coffe a mcdonalds. Too funny people worrying about the cost of the electricity for an electric bike. If we have a power outage, I'll just fire up a small generator and among other things, charge my bike.
 
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