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  #11  
Old October 4th 11, 09:46 AM posted to aus.bicycle
Rob
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On 4/10/2011 4:01 PM, Phil H wrote:
On Sep 30, 4:31 pm, wrote:

Do they or can they reverse the flow when going downhill to recharge the
battery? Like the electric trains up and down the Blue Mountains putting
power back into the grid?


Regenerative braking is a fairly common feature on electric bike motor
controllers, or it was last time I looked. However, I think it's more
of a feel-good thing than a practical feature; the cumulative
inefficiencies involved mean that of the energy that goes into getting
the bike moving, only a very small proportion ends up back in the
battery.


-- Phil


Well why can't there be a generator on the front hub feeding the battery
- that would be topping it up all the time. Wonder how that would
translate into horse power loss of efficiency of the rear motor to drive
the generator?
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  #12  
Old October 4th 11, 11:16 AM posted to aus.bicycle
F Murtz[_2_]
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Posts: 193
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Rob wrote:
On 4/10/2011 4:01 PM, Phil H wrote:
On Sep 30, 4:31 pm, wrote:

Do they or can they reverse the flow when going downhill to recharge the
battery? Like the electric trains up and down the Blue Mountains putting
power back into the grid?


Regenerative braking is a fairly common feature on electric bike motor
controllers, or it was last time I looked. However, I think it's more
of a feel-good thing than a practical feature; the cumulative
inefficiencies involved mean that of the energy that goes into getting
the bike moving, only a very small proportion ends up back in the
battery.


-- Phil


Well why can't there be a generator on the front hub feeding the battery
- that would be topping it up all the time. Wonder how that would
translate into horse power loss of efficiency of the rear motor to drive
the generator?



Here we go again, you get nothing for nothing.
  #13  
Old October 4th 11, 01:54 PM posted to aus.bicycle
terryc
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Posts: 134
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John Henderson wrote:

That 200W limit is Australia-wide (enshrined in the Australian
Road Rules).


When did that happen?
  #14  
Old October 4th 11, 01:55 PM posted to aus.bicycle
terryc
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Posts: 134
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Fraser Johnston wrote:
On 22/09/11 1:45 PM, Zebee Johnstone wrote:


As far as I know the conversion is "replace the wheel with the
hub motor one, locate the battery somewhere, run the cables."



I'm thinking illegal.


Why?
Is the motor power more than allowed in your state?
  #15  
Old October 4th 11, 11:29 PM posted to aus.bicycle
Phil H[_2_]
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Posts: 21
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On Oct 4, 7:46*pm, Rob wrote:

Well why can't there be a generator on the front hub feeding the battery
- that would be topping it up all the time. *Wonder how that would
translate into horse power loss of efficiency of the rear motor to drive
the generator?


To paraphrase Homer Simpson: in this country we obey the laws of
thermodynamics!

You're describing perpetual motion. It wouldn't work.


-- Phil
  #16  
Old October 5th 11, 12:22 AM posted to aus.bicycle
Rob
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Posts: 107
Default E Bikes

On 5/10/2011 9:29 AM, Phil H wrote:
On Oct 4, 7:46 pm, wrote:

Well why can't there be a generator on the front hub feeding the battery
- that would be topping it up all the time. Wonder how that would
translate into horse power loss of efficiency of the rear motor to drive
the generator?


To paraphrase Homer Simpson: in this country we obey the laws of
thermodynamics!

You're describing perpetual motion. It wouldn't work.


-- Phil



Maybe the word topping up isn't correct. I know you don't have perpetual
motion.

What I was suggesting was placing energy back into the battery so as to
extend the range of the charge, even if it was only 10%.
  #17  
Old October 5th 11, 12:31 AM posted to aus.bicycle
tomasso
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Posts: 13
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"Rob" wrote in message ...
On 5/10/2011 9:29 AM, Phil H wrote:
On Oct 4, 7:46 pm, wrote:

Well why can't there be a generator on the front hub feeding the battery
- that would be topping it up all the time. Wonder how that would
translate into horse power loss of efficiency of the rear motor to drive
the generator?


To paraphrase Homer Simpson: in this country we obey the laws of
thermodynamics!

You're describing perpetual motion. It wouldn't work.


-- Phil



Maybe the word topping up isn't correct. I know you don't have perpetual
motion.

What I was suggesting was placing energy back into the battery so as to
extend the range of the charge, even if it was only 10%.


Good way to get fitter and lose a bit of weight.

T.
  #18  
Old October 5th 11, 08:02 AM posted to aus.bicycle
F Murtz[_2_]
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Posts: 193
Default E Bikes

Rob wrote:
On 5/10/2011 9:29 AM, Phil H wrote:
On Oct 4, 7:46 pm, wrote:

Well why can't there be a generator on the front hub feeding the battery
- that would be topping it up all the time. Wonder how that would
translate into horse power loss of efficiency of the rear motor to drive
the generator?


To paraphrase Homer Simpson: in this country we obey the laws of
thermodynamics!

You're describing perpetual motion. It wouldn't work.


-- Phil



Maybe the word topping up isn't correct. I know you don't have perpetual
motion.

What I was suggesting was placing energy back into the battery so as to
extend the range of the charge, even if it was only 10%.


Only if you put more in,like pedal harder.
  #19  
Old October 5th 11, 08:58 AM posted to aus.bicycle
John Henderson
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Posts: 413
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terryc wrote:

John Henderson wrote:

That 200W limit is Australia-wide (enshrined in the Australian
Road Rules).


When did that happen?


Earlier, rather than later IIRC. The earliest copy I've got is
2008, but it was there before then.

John
  #20  
Old October 5th 11, 09:06 AM posted to aus.bicycle
John Henderson
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Posts: 413
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Rob wrote:

What I was suggesting was placing energy back into the battery so as to
extend the range of the charge, even if it was only 10%.


On your proposal, is the charging done only when the brakes are
applied?

If so, it'd require specialized brake levers with a switch.
Output of hub generators is typically 3W - given losses, much
closer than 1% of drive motor output than 10%, and only for the
short time spent braking.

If it's charging all the time, it would require extra rider
effort to produce that extra 3W. Either that or it (and more
to compensate for losses) will be drawn from the battery,
reducing both short and long term battery life.

John
 




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