EV Digest 4516
Topics covered in this issue include:
1) The rest of the list...
by Jeff Shanab <[EMAIL PROTECTED]>
2) RE: One-way clutch (was Freewheel...)
by Jeff Shanab <[EMAIL PROTECTED]>
3) Flooded battery advice, terminals
by "Mark Hanson" <[EMAIL PROTECTED]>
4) Re: PFC Chargers...Let's hear the Positive Side!
by "ProEV" <[EMAIL PROTECTED]>
5) A few questions
by "Stu or Jan" <[EMAIL PROTECTED]>
6) RE: One-way clutch (was Freewheel...)
by "Stu or Jan" <[EMAIL PROTECTED]>
7) March race report up for Kokam powered Electric Imp
by "ProEV" <[EMAIL PROTECTED]>
8) Re: Not if you have EV's, Re: Exciting - No gasoline in Northwest Florida
by Neon John <[EMAIL PROTECTED]>
9) Re: One-way clutch (was Freewheel...)
by Neon John <[EMAIL PROTECTED]>
10) Re: Question about Peukert Exponent
by Neon John <[EMAIL PROTECTED]>
11) Re: Question about Peukert Exponent
by Neon John <[EMAIL PROTECTED]>
12) Re: A few questions
by Ryan Stotts <[EMAIL PROTECTED]>
13) Re: Question about Peukert Exponent
by Eric Poulsen <[EMAIL PROTECTED]>
14) RE: A few questions
by "Stu or Jan" <[EMAIL PROTECTED]>
15) Re: A few questions
by Evan Tuer <[EMAIL PROTECTED]>
16) Re: Flooded battery advice, terminals
by "David Roden" <[EMAIL PROTECTED]>
17) Re: A few questions
by Eric Poulsen <[EMAIL PROTECTED]>
18) RE: One-way clutch (was Freewheel...)
by reb <[EMAIL PROTECTED]>
19) Re: A few questions
by reb <[EMAIL PROTECTED]>
20) Re: A few questions
by reb <[EMAIL PROTECTED]>
21) Re: A few questions
by "damon henry" <[EMAIL PROTECTED]>
22) Re: A few questions
by Evan Tuer <[EMAIL PROTECTED]>
23) RE: One-way clutch (was Freewheel...) bicycle components
by "Stu or Jan" <[EMAIL PROTECTED]>
24) Re: One-way clutch (was Freewheel...) bicycle components
by Eric Poulsen <[EMAIL PROTECTED]>
25) RE: One-way clutch (was Freewheel...)
by "Paschke, Stephen" <[EMAIL PROTECTED]>
26) Roller chain question -- large breakers?
by Eric Poulsen <[EMAIL PROTECTED]>
27) RE: One-way clutch (was Freewheel...) COASTING!
by "Stu or Jan" <[EMAIL PROTECTED]>
28) Re: One-way clutch (was Freewheel...) COASTING!
by Evan Tuer <[EMAIL PROTECTED]>
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When I have recieved that I was still able to view source(ctrl-u,
mozilla on linux and windows) and see the messages below it. Only the
offending message was cut, but the list server kills the link to the
next header. Because I am in digest mode, my email client just stops
displaying at that point.
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I would b pleasently surprized if the bicycle freewheel held up under
the conditions the etek could produce. First they get part of they're
strenth by always loading in double shear, and secondly there is a
guarranty that the torque will drop off as rpm climbs. The etek may be
able to continue to produce torque as the rpm climbs and I think they
will wear quickly. The moutain bike single speed freewheels are indeed
a stronger beast. What is the intended application?
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--- Begin Message ---
No need to order special terminals on floodeds for the proper automotive
clamps, just zing off the battery post studs with a SawZall (reciprocating
jig-saw). If I have the height, I'll put a nut, washer and lock washer on
top to keep the automotive terminal clamp from coming loose.
Mark
----- Original Message -----
From: "David (Battery Boy) Hawkins" <[EMAIL PROTECTED]>
To: "EV Discussion List" <[email protected]>
Sent: Wednesday, July 20, 2005 8:52 PM
Subject: Re: 12v Flooded battery advice.
> David and All,
> Looking at battery notes from my last purchase (18,000 miles ago 08/03),
> yes US batteries would have been cheaper than Trojan ($54 each at 24), but
> shipping would have been $300 or $1596 for a pack. Dave Mason with U.S.
> mentioned that although they would still sell directly to EV'ers, they no
> longer liked doing that as it undercuts their local representatives. I
> ended up paying $79 each (retail for one was $112!), or $1896 for a pack
of
> Trojan T-145's (special order for automotive terminals) that only took
> three weeks to get through a local distributor (that is a DEVC club
> sponsor). Since I had heard that Trojan's last 20-40% more miles than
U.S.,
> which Mark Hanson mentions below, and I couldn't share shipping costs with
> someone else on a larger U.S. order at the time (and really don't like
> changing batteries more often), the Trojan seemed like a better deal at
the
> time.
> Hope this helps,
> Dave (B.B.) Hawkins
> Member of the Denver Electric Vehicle Council:
> http://www.devc.org/
> Card carrying member and former racer with The National Electric Drag
> Racing Association:
> http://www.nedra.com/
> Lyons, CO
> 1979 Mazda RX-7 EV (192V of YT's for the teenagers)
> 1989 Chevy S10 Ext. Cab (144V of floodies, for Ma and Pa only!)
>
>
> >From: "David Roden" <[EMAIL PROTECTED]>
> >Date: Wed, 20 Jul 2005 03:23:13 -0400
> >
> <snip>
> >Interstate Workaholic is the same as US Battery. Generally USBMC
products
> >are significantly less costly. They will sell directly to EV hobbyists
at
> >discount, and will give you whatever type of terminals you want. They've
> >been supportive of hobbyist EV activities for at least 25 years.
> >
> >Trojan has a slightly better rep, but they cost more and I've never known
> >them to deal with EVers directly. Around here, they are priced close to
> >list almost everywhere (if you can find them). Terminals are usually
"take
> >what they give you." Trojan don't particularly care about EV hobbyists,
> >from what I can tell, but others may have an update on that.
> >
> >Between these two, in practice, maintenance and charging regime will
> >probably make more difference in cycle life than brand will.
> >
> >Floor sweeper batteries' construction is rather similar to golf car
> >batteries'. In theory they should last almost as long. They don't seem
to
> >in many cases, but I think that may be partly because people who use them
> >tend to push them harder. They will almost certainly give longer service
> >than flooded marine batteries though.
> >
> >
> >David Roden - Akron, Ohio, USA
>
>
>
> >From: "Mark Hanson" <[EMAIL PROTECTED]>
> >To: "jerry dycus" <[EMAIL PROTECTED]>, <[email protected]>
> >Subject: Re: Trojan vs US batt, US batt phone number? Re: 12v Flooded
> >battery advice.
> >Date: Tue, 19 Jul 2005 09:05:38 -0400
> >MIME-Version: 1.0
> >
> >US Battery at 653 Industrial Park Dr., Evans, Georgia is 1-800-522-0945
and
> >Terry Agrileus at X20 is whom I ordered previously. Nuaz Kareshi - eng
is
> >the California location at 1-800-695-0945 and previously worked at
Trojan.
> >I get about 10k miles out of US and about 12-14k miles from Trojans over
the
> >last 30 years with 6v'ers doing about 1-2k miles better than 8v'ers.
Best
> >cost per mile was the USBatt 6V'ers as Trojan's have become pricey. I
> >presently got a set of Exide's from Sam's in Jan and they replaced a dud
(in
> >4 months) for free. I tried sealed batts once but the cost per mile was
> >poor.
>
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Roger Stockton wrote:
Your generator was rated fairly accurately; you just forgot that your
charger is not 100% efficient.
330V @ 12A = 3960W (3.96kW) output. At 90% efficiency, the input power
is 4400W (4.4kW). Add to this the fact that while the PFC's power
factor is quite good, it still isn't perfect, and you were probably
running the genset right at or just over its rated output.
Good point. On top of which I suspect we should have de-rated it some for
the 95 degree heat and high humidity.
David Roden wrote:
<I read that as 10 amps from the mains. If indeed it was 10 amps at the
EV's
battery, I agree that there's no cause for concern.>
It was 10 amps into the EV pack.
Rich Rudman wrote:
<The big point is you can find a power level where it will work, You have
options, and a variable power level. This enables ALOT of other wise
useless solutions.>
Exactly! The ability to control the power draw of the PFC charger meant that
we could make use of some sub-par 'opportunity charging' options. On a road,
this could be the difference between getting home and getting towed.
Cliff
www.ProEV.com
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1> Do motorcycles have freewheels at their rear axle?
2> What would you use instead of a freewheel to manually
couple/uncouple 2 horizontal drive shafts?
stU
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I have a freewheel on my not finished hybrid. The teeth are for a 40/41
chain if that means anything regarding its strength. I will power one with
a 6.5 hp B&S and the other with an 8" 36V 80 Amp motor to be run at 48 v.
I'll let you know when I use it how well they hold up.
stU
-----Original Message-----
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On
Behalf Of Jeff Shanab
Sent: Thursday, July 21, 2005 2:27 AM
To: Electric Vehicle Discussion List
Subject: RE: One-way clutch (was Freewheel...)
I would b pleasently surprized if the bicycle freewheel held up under
the conditions the etek could produce. First they get part of they're
strenth by always loading in double shear, and secondly there is a
guarranty that the torque will drop off as rpm climbs. The etek may be
able to continue to produce torque as the rpm climbs and I think they
will wear quickly. The moutain bike single speed freewheels are indeed
a stronger beast. What is the intended application?
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Hi Everybody,
I don't think I have posted here that we have added a race report from our
weekend at Moroso in March to our website www.ProEV.com. We finished second
in class. It took a bit of 'tortoise and hare' strategy and a lot of luck to
beat 3 out the other 4 cars. There is lots of pictures and a graph with our
data on watt-hours per racing mile and how much regen helps.
Also up is the April Autocross. Another victory, keeping us undefeated in
class but we almost threw it away. Watch the videos to see what happens when
you run too tall tires on a very low car.
Enjoy
Cliff
www.ProEV.com
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The sun just came out here for the first day since the start of the
hurricane season at the first of the month. What would you do in that
instance? Usually the whole month of January and most of February are
also socked in. Solar doesn't work too well over here on the Right
coast. That's why I have a super-quiet generator. I love not hearing
my generator running :-)
I tried the solar thing (water and electricity) back in the 70s on my
first house. TVA paid me to do it :-) They looked purty on my roof
but they didn't do much, at least not when I needed it. Plenty of hot
water in the summer when the incoming cold water was about 85 deg.
But in the depths of winter, nada.
John
On Wed, 20 Jul 2005 23:20:49 -0700 (PDT), Reverend Gadget
<[EMAIL PROTECTED]> wrote:
>I have a forty foot bus conversion with eight solar
>panels and a trailer with seven more. It gives me a
>total of 1.7 k of capacity. I use the excess power to
>heat my water with propane to top off the evening if
>needed. It runs my fridge, toilet, stove, and all my
>lights with enough extra to run my artcar at
>burningman. I have a 3.5k inverter with a 1000
>amphaour battery pack. I haven't had to plug the thing
>in in three years! we had a power outage yesterday and
>the wife and I went out to the bus to watch tv. I love
>not having a generator running.
---
John De Armond
See my website for my current email address
http://www.johngsbbq.com
Cleveland, Occupied TN
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As someone else mentioned in passing, most of the motion control
companies make one-way clutches in standard bearing dimensions. This
device presses into a standard bearing bore and can run on a polished
non-hardened shaft. A familiar EV application was the Currie scooter.
* For the ETEK one could do any of the following:
* Get an ETEK without the keyed shaft, if possible.
* Turn the shaft down to remove the keyway.
* Weld up the key slot and turn the shaft to the original diameter.
* Fit a sleeve, optionally with a key, to the shaft. This will
probably jack the shaft size up to at least an inch and a quarter
which will limit the minimum sprocket size.
My choice, and what I'm going to do with mine, is to turn the shaft
down to remove the keyway AND to give me the option of lower tooth
counts. I'll probably go down to a half inch. I'm going to try to
mount the ETEK in the lathe and turn the shaft using the ETEK itself
to rotate the shaft.
In my testing with small EVs, mostly 2 and three wheel scooters, the
one-way freewheel clutch provides much more range extension than
regen. The reason is that the EV is in motion much more than it is
braking. With the freewheel, one can blip the throttle every so
often, like kicking a spinning top to keep it spinning, and otherwise
coast. I can almost double the range of my dual motor Currie by using
this method over holding a steady throttle.
John
On Thu, 21 Jul 2005 06:27:14 +0000, Jeff Shanab
<[EMAIL PROTECTED]> wrote:
>I would b pleasently surprized if the bicycle freewheel held up under
>the conditions the etek could produce. First they get part of they're
>strenth by always loading in double shear, and secondly there is a
>guarranty that the torque will drop off as rpm climbs. The etek may be
>able to continue to produce torque as the rpm climbs and I think they
>will wear quickly. The moutain bike single speed freewheels are indeed
>a stronger beast. What is the intended application?
>
---
John De Armond
See my website for my current email address
http://www.johngsbbq.com
Cleveland, Occupied TN
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On Thu, 21 Jul 2005 04:15:22 -0500, Danny Miller
<[EMAIL PROTECTED]> wrote:
>Here is what I am unclear on. At the end of the high discharge case,
>are 100 amp-hrs drained from the battery leaving its state-of-charge at
>0%, or are 75 amp-hrs drained and the state of charge is only down to
>25% but the battery can no longer sustain 50 amps without the terminal
>voltage falling below the specified 10.5v?
>
>To state it another way, in terms of practical consequences, after
>draining 75 amp-hrs at 50 amps, does the battery still contain another
>25 amp-hrs if only a light load is applied?
yes. What Peukert does is try to model the cumulative effects of
polarization, electrolyte starvation, depletion of active material on
the surface of the paste(s), ohmic loss and probably a few other
things.
I'd like to see a controller that does Peukert (or some other, more
conforming algorithm) internally and manages the battery draw to get
the max power from the pack. As the Peukert limit is approached at a
given amp draw, back the draw down as appropriate and supply whatever
power is available to the traction motor. This is similar in concept
to the constant power solar controllers.
Instead of the precipitous drop that a conventional pack experiences
at the end of Peukert, with this type of controller, the power would
gradually but controllably drop off. One might only be able to creep
home but one probably could get home and do so without damaging the
pack.
John
---
John De Armond
See my website for my current email address
http://www.johngsbbq.com
Cleveland, Occupied TN
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On Thu, 21 Jul 2005 12:18:49 +0200, Emil Naepflein
<[EMAIL PROTECTED]> wrote:
>There was a nice paper available for which I posted a reference some
>time ago which explained the chemical process as introduction to a new
>concept for a energy gauge. But the link is invalid now and I didn't
>store the document. May be someone else can provide the PDF to you.
>
>The original link was:
>http://www.ee.ncue.edu.tw/note/data/o/21/91.pdf
>
>You can get a html version without images at:
>http://66.249.93.104/search?q=cache:Z5sTP1vku78J:www.ee.ncue.edu.tw/note/data/o/21/91.pdf+o/21/91.pdf&hl=de&client=firefox-a
Here it is on my web site. Use this direct link, as I haven't put it
on a page yet.
http://www.johngsbbq.com/Neon_John_site/EV/Energy_Gauge_for_Lead-Acid_Batteries.pdf
John
---
John De Armond
See my website for my current email address
http://www.johngsbbq.com
Cleveland, Occupied TN
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Stu wrote:
> 1> Do motorcycles have freewheels at their rear axle?
No, the sprocket is bolted to the wheel:
http://www.honda.co.jp/parts/hop/motorcycle/colorspirit/image/chain_normal.jpg
> 2> What would you use instead of a freewheel to manually
> couple/uncouple 2 horizontal drive shafts?
A clutch of some sort.
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Some thoughts:
At higher currents, the amount of energy wasted as heat by the internal
resistance of the battery goes up.
I've read somewhere that despite peukerts the extra Ah are not totally
"lost," and that if you let a "dead" battery (that has been discharged
at a high rate) rest for several hours, that you can extract most of the
remaining Ah.
Danny Miller wrote:
Hi, I was trying to understand exactly how the Peukert Exponent
works. I've read what's out on the web, most is the same thing copied
over and over again but I'm having trouble buying exactly what seems
to be said. (I'm an experienced EE, current, voltage, amp-hrs are
quite well understood). For the sake of this question, please put
aside the additional issues of how unwise it is to totally drain
batteries and such, I'm interested in what Peukert's Exp truly means.
OK, so a 100 amp-hr lead acid battery will yield 100 amp-hrs at a low
discharge rate. That would be until the terminal voltage reaches 10.5v.
And say that same battery under 50 amps load yields only 75 amp-hrs.
I understand this to mean that this still means the capacity until the
terminal voltage reaches 10.5v.
Here is what I am unclear on. At the end of the high discharge case,
are 100 amp-hrs drained from the battery leaving its state-of-charge
at 0%, or are 75 amp-hrs drained and the state of charge is only down
to 25% but the battery can no longer sustain 50 amps without the
terminal voltage falling below the specified 10.5v?
To state it another way, in terms of practical consequences, after
draining 75 amp-hrs at 50 amps, does the battery still contain another
25 amp-hrs if only a light load is applied?
Frankly, I don't see how higher rates of current would mean that each
amp-hr would consume more reagents inside the cell. Thus a better way
of expressing Peukert's would be an expression that at "x"%
state-of-charge the battery can sustain "y" amps without dropping
below 10.5v. However I've never seen it stated that way and I am
uncertain as to what is going on here, logically this more useful form
of the relationship should have been easy to run across if it is
representative of what will happen in reality.
Thanks,
Danny Miller
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> 2> What would you use instead of a freewheel to manually
> couple/uncouple 2 horizontal drive shafts?
A clutch of some sort.
I was thinking of using a non-friction coupling. For example a deep impact
3/4" socket wrench onto a hex rod, or a female splined sleeve onto a 2 piece
splined driveshaft.
A throw out yoke could be moved via a brake lever/cable etc. One would need
to bridge only a fraction of an inch to connect.
stU
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On 7/21/05, Stu or Jan <[EMAIL PROTECTED]> wrote:
>
> > 2> What would you use instead of a freewheel to manually
> > couple/uncouple 2 horizontal drive shafts?
>
> A clutch of some sort.
> I was thinking of using a non-friction coupling. For example a deep impact
> 3/4" socket wrench onto a hex rod, or a female splined sleeve onto a 2 piece
> splined driveshaft.
>
> A throw out yoke could be moved via a brake lever/cable etc. One would need
> to bridge only a fraction of an inch to connect.
The correct term is a dog clutch.
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On 21 Jul 2005 at 9:33, Mark Hanson wrote:
> No need to order special terminals on floodeds for the proper automotive
> clamps, just zing off the battery post studs with a SawZall (reciprocating
> jig-saw).
That's quick and dirty, but I've destroyed the seal between the post and the
top doing that. A hacksaw is slower but safer. Maybe bolt cutters?
David Roden - Akron, Ohio, USA
EV List Assistant Administrator
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Stu or Jan wrote:
1> Do motorcycles have freewheels at their rear axle?
Absolutely not. That's what clutches are for. Bicycles only have them
so you don't have to take your feet off the pedals when you want to stop
pedalling. If they had freewheels, engine braking (downshifting) would
be impossible.
With an electric motorcycle, you still wouldn't need a freewheel or a
clutch for exactly the same reason you don't need either on an EV -- no
reason the wheel shouldn't spin the unpowered motor when coasting.
2> What would you use instead of a freewheel to manually
couple/uncouple 2 horizontal drive shafts?
A freewheel is essentially a mechanical diode -- it only transmits
rotational energy (torque) in one direction. As such, it doesn't
completely uncouple. There are "two-way" sprag clutches -- essentially
they only engage *in either direction* when the torque comes from the
"input" side of the clutch.
You could also use some sort of clutch, be it friction (friction plates
or belt tension), or dogged (like most standard transmission gearing).
The dogged solution will only work under no-torque conditions, which is
fine for an electric vehicle: take foot off accellerator, shift, put
foot back. There are electrically, hydraulically (very common),
mechanically (very common) and pneumatically actuated clutches available.
Another solution is to use some sort of gear that "pops-between" two
other gears, making the coupling. This is not recommended for anything
larger than the 3 volt motor in a toy car.
Most (all, really) motorcycle transmissions have square dog teeth for
the gears without any synchros, and it's not uncommon to shift these,
*even under power*.
All of these devices are relatively easily obtainable from industrial
supply. Most of the time, for the shaft speeds associated for
automotive use, you'll need an unenclosed type that has to run in an oil
bath (i.e. in a transmission case) for cooling and lube.
stU
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for what it's worth ..........
having used free wheels on my etek mountain bike :-
use a good quality freewheel and you will never break
it
at 48v
the problem is the chain
bicycle chains are designed to have a lot of sideways
movement for cassettes etc and they are not like an
industrial or motorcycle chain
they streach really badly and then they come off the
sprockets
i found that you could wreck a chain in 3hrs use if
you were heavy on the throttle
two snapped during hard launches one of these were
brand new
the solution i used in the end was to use a
centrifugal clutch on the etek and wind the regen up
on the controller so the clutch dropped out nice and
quickly
i used DID go kart chain in the end and it worked fine
the clutch i used was a noram unit with needle rolers
in i had to try three sets of springs before i got
the right grab rate
reb
--- Jeff Shanab <[EMAIL PROTECTED]> wrote:
> I would b pleasently surprized if the bicycle
> freewheel held up under
> the conditions the etek could produce. First they
> get part of they're
> strenth by always loading in double shear, and
> secondly there is a
> guarranty that the torque will drop off as rpm
> climbs. The etek may be
> able to continue to produce torque as the rpm climbs
> and I think they
> will wear quickly. The moutain bike single speed
> freewheels are indeed
> a stronger beast. What is the intended application?
>
>
___________________________________________________________
Yahoo! Messenger - NEW crystal clear PC to PC calling worldwide with voicemail
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1 no
2 some sort of clutch
(electro mechanical/fluid/centrefugal , whatever takes
your fancy)
reb
--- Stu or Jan <[EMAIL PROTECTED]> wrote:
> 1> Do motorcycles have freewheels at their rear
> axle?
>
> 2> What would you use instead of a freewheel to
> manually
> couple/uncouple 2 horizontal drive shafts?
>
> stU
>
>
___________________________________________________________
Yahoo! Messenger - NEW crystal clear PC to PC calling worldwide with voicemail
http://uk.messenger.yahoo.com
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dog clutches are only any use if the shaft speed is
low and the load on the output shaft very small
otherwise the dogs bounce (too fast) and the whole
thing lurches when it hooks up
i had an old atco lawn mower with a dog clutch and if
you were warming it up on a fast idle and engaged the
drive by mistake it would hook up , leap out of my
hands and race across the garden on it's own
most dog gear boxes have some sort of friction clutch
to allow selection with no load
reb
--- Evan Tuer <[EMAIL PROTECTED]> wrote:
> On 7/21/05, Stu or Jan <[EMAIL PROTECTED]> wrote:
> >
> > > 2> What would you use instead of a
> freewheel to manually
> > > couple/uncouple 2 horizontal drive shafts?
> >
> > A clutch of some sort.
> > I was thinking of using a non-friction coupling.
> For example a deep impact
> > 3/4" socket wrench onto a hex rod, or a female
> splined sleeve onto a 2 piece
> > splined driveshaft.
> >
> > A throw out yoke could be moved via a brake
> lever/cable etc. One would need
> > to bridge only a fraction of an inch to connect.
>
> The correct term is a dog clutch.
>
>
___________________________________________________________
Yahoo! Messenger - NEW crystal clear PC to PC calling worldwide with voicemail
http://uk.messenger.yahoo.com
--- End Message ---
--- Begin Message ---
With an electric motorcycle, you still wouldn't need a freewheel or a
clutch for exactly the same reason you don't need either on an EV -- no
reason the wheel shouldn't spin the unpowered motor when coasting.
After pulling a long hill and substantially heating my motor, I'm glad to
have the motor spinning on the way down to allowing the internal fan to cool
it down.
damon
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On 7/21/05, reb <[EMAIL PROTECTED]> wrote:
> dog clutches are only any use if the shaft speed is
> low and the load on the output shaft very small
> otherwise the dogs bounce (too fast) and the whole
> thing lurches when it hooks up
Yeah, I didn't say it was the correct solution mind :)
> most dog gear boxes have some sort of friction clutch
> to allow selection with no load
Quite. Commonly used on boats - the propellor doesn't present much
load at idle. You also find dog clutches in those horrible 4wd
things, the kind where you have to stop to engage the drive.
--
EVan
http://www.tuer.co.uk/evs2
--- End Message ---
--- Begin Message ---
Implied in this discussion is that the bicycle chain can also take the
torque.
I assume that you are using 3/32" chain. Have you ever broken any?
It would seem that a parallel mountain bike drive line might be very robust.
Is it possible to parallel a pair of freewheels?
stU
-----Original Message-----
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On
Behalf Of Peter VanDerWal
Sent: Thursday, July 21, 2005 9:07 AM
To: [email protected]
Subject: RE: One-way clutch (was Freewheel...)
> Disclaimer: I know almost zip about bicycle mechanicals.
Yup, you're right about that.
>
> I do know a good cyclist has a peak of only around 2 hp, and not for very
> long.
And a VERY good cyclist (sprinter) can put out 3 hp:
http://worldofendurance.com/article.asp?a_id=1013851
That's 100 flbs at 90rpm. As RPM drops the torque you can produce goes
up. At low RPMs, they can produce HUNDREDS of ft/lbs.
I can generate over 200 lbs at the crank (at low rpm), and I'm nowhere
close to what a pro can generate.
FWIW I break rear wheel spokes on a regular basis. In fact I bought a new
set of wheels, that retail for over $500 (shimano R-540), because the bike
shop owner assured me that "Nobody breaks spokes on these wheels".
Now when I show up he says, "ok, nobody but YOU breaks spokes on these
wheels". I broke three spokes in the first year.
I've broken pedals and once a crank. I have to replace my chain every year
because it's starting to stretch.
I've NEVER broken a freewheel. In fact I've never heard of anyone
breaking a freewheel.
> An Etek can produce 15 hp peak, 7 hp continuously. But it's torque
> more than hp that limits a bicycle freewheel. Some cyclists can produce a
> staggering amount of force at the pedal, but what can be applied to the
> freewheel is limited by the bike's configuration (it just does a wheelie).
This is true, sort of. In low gear, with my hands on the drops and my
butt on the saddle I can lift the front wheel easily and ride a wheelie.
To prevent this from happening, you just have to stand up (more torque and
moves you center of gravity forward). For even more torque you can lean
over the handle bars and pull UP on them generating even more torque and
still keeping the front wheel down.
What to the Tour and look at the sprint for the finish. All of the riders
are standing up, leaning forward, and yanking up on the bars so they can
push down harder on the pedals.
> Bottom line, a bicycle freewheel won't take much. A bicycle expert would
> be able to give you numbers.
My road bike's freewheel can easily handle the 150+ ft/lbs I can push
through it. A pro cyclist could probably put twice that through theirs.
Mountain bike freewheels see even more torque due to granny gears.
>
> If a bicycle freewheel is a ratchet mechanism, using two in parallel would
> require aligning them properly so they both carry equal load. Do it wrong
> and the second freewheel does nothing but add weight and complexity.
>
Quite right. However just one could easily handle the power from
something like an Etek as long as you used it on the low torque (motor)
side of the power train.
> My gut feeling is that bicycle components have been refined over a very
> long
> history to handle the loads of their target application while minimizing
> weight. It is not likely that they will be a good choice in an
> application where the potential power is increased by a factor of two or
> three.
It's true that weight is a major concern, however strength is also a
predominant factor. It wouldn't due to have someone loose a race because
of equipment failure. The good quality components are designed to handle
the maximum power that ANY human can produce and probably a bit more, just
to be sure.
However, a lot of the really light weight components have weight limits.
They sacrifice strength to save weight. That's one of the reasons I don't
have any titanium components on my bike. This is also one of the reasons
that most cycling competitions have a minimum allowable bicycle weight
(usually 16 lbs).
Cheers, Pete
--- End Message ---
--- Begin Message ---
Stu or Jan wrote:
Implied in this discussion is that the bicycle chain can also take the
torque.
Technically speaking, you can't apply torque to a chain, only tension.
Smaller sprockets mean more tension.
I assume that you are using 3/32" chain. Have you ever broken any?
It would seem that a parallel mountain bike drive line might be very robust.
Is it possible to parallel a pair of freewheels?
Why not just use a double-width chain, or simply a larger chain?
--- End Message ---
--- Begin Message ---
I agree with you pete. If you use a bicycle freewheel you need to get a good
heavy duty one such as one from a mid to hi end mtnbike or a good bmx
freewheel. I have broke a couple freewheels about 10 years ago. One was good
quality but I put several thousand miles on it, I was racing a lot back then.
I think about 4 or 5 hp would be the limit on a freewheel or you will be
replacing them
very quickly
> Stephen Paschke
> Senior Consultant
> Keane, Inc.
-----Original Message-----
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]
Behalf Of Peter VanDerWal
Sent: Thursday, July 21, 2005 7:07 AM
To: [email protected]
Subject: RE: One-way clutch (was Freewheel...)
> Disclaimer: I know almost zip about bicycle mechanicals.
Yup, you're right about that.
>
> I do know a good cyclist has a peak of only around 2 hp, and not for very
> long.
And a VERY good cyclist (sprinter) can put out 3 hp:
http://worldofendurance.com/article.asp?a_id=1013851
That's 100 flbs at 90rpm. As RPM drops the torque you can produce goes
up. At low RPMs, they can produce HUNDREDS of ft/lbs.
I can generate over 200 lbs at the crank (at low rpm), and I'm nowhere
close to what a pro can generate.
FWIW I break rear wheel spokes on a regular basis. In fact I bought a new
set of wheels, that retail for over $500 (shimano R-540), because the bike
shop owner assured me that "Nobody breaks spokes on these wheels".
Now when I show up he says, "ok, nobody but YOU breaks spokes on these
wheels". I broke three spokes in the first year.
I've broken pedals and once a crank. I have to replace my chain every year
because it's starting to stretch.
I've NEVER broken a freewheel. In fact I've never heard of anyone
breaking a freewheel.
> An Etek can produce 15 hp peak, 7 hp continuously. But it's torque
> more than hp that limits a bicycle freewheel. Some cyclists can produce a
> staggering amount of force at the pedal, but what can be applied to the
> freewheel is limited by the bike's configuration (it just does a wheelie).
This is true, sort of. In low gear, with my hands on the drops and my
butt on the saddle I can lift the front wheel easily and ride a wheelie.
To prevent this from happening, you just have to stand up (more torque and
moves you center of gravity forward). For even more torque you can lean
over the handle bars and pull UP on them generating even more torque and
still keeping the front wheel down.
What to the Tour and look at the sprint for the finish. All of the riders
are standing up, leaning forward, and yanking up on the bars so they can
push down harder on the pedals.
> Bottom line, a bicycle freewheel won't take much. A bicycle expert would
> be able to give you numbers.
My road bike's freewheel can easily handle the 150+ ft/lbs I can push
through it. A pro cyclist could probably put twice that through theirs.
Mountain bike freewheels see even more torque due to granny gears.
>
> If a bicycle freewheel is a ratchet mechanism, using two in parallel would
> require aligning them properly so they both carry equal load. Do it wrong
> and the second freewheel does nothing but add weight and complexity.
>
Quite right. However just one could easily handle the power from
something like an Etek as long as you used it on the low torque (motor)
side of the power train.
> My gut feeling is that bicycle components have been refined over a very
> long
> history to handle the loads of their target application while minimizing
> weight. It is not likely that they will be a good choice in an
> application where the potential power is increased by a factor of two or
> three.
It's true that weight is a major concern, however strength is also a
predominant factor. It wouldn't due to have someone loose a race because
of equipment failure. The good quality components are designed to handle
the maximum power that ANY human can produce and probably a bit more, just
to be sure.
However, a lot of the really light weight components have weight limits.
They sacrifice strength to save weight. That's one of the reasons I don't
have any titanium components on my bike. This is also one of the reasons
that most cycling competitions have a minimum allowable bicycle weight
(usually 16 lbs).
Cheers, Pete
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--- End Message ---
--- Begin Message ---
This one probably Roderick or FT can answer:
I've used a "chain breaker" for both bicycle and motorcycle roller
chains. It pushes out (or in) the pin that connects links so that you
can make a chain longer and shorter by splicing.
I've kind of poked around da net, but I cannot determine if there is
such a thing for the double or triple-width chains.
Anyone?
--- End Message ---
--- Begin Message ---
AHAH! COASTING! EXACTLY!
Why is a bicycle the most efficient form of transportation? Coasting
perhaps.
You are not using energy throughout the complete pedal cycle.
I am sure glad that you wrote that coasting is 'more better' than regen in
an EV.
Use regen for braking in addition with a mechanical/electric clutch
freewheel for coasting and we would have something. Perhaps second best
would be to do it at the jackshaft stage. It would add a little more
friction for coasting.
What I was getting at was a mechanical coupling that could be 'throw out'
bearing deployed to choose either coast or regen.
stU
-----Original Message-----
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On
Behalf Of Neon John
Sent: Thursday, July 21, 2005 10:48 AM
To: [email protected]
Subject: Re: One-way clutch (was Freewheel...)
As someone else mentioned in passing, most of the motion control
companies make one-way clutches in standard bearing dimensions. This
device presses into a standard bearing bore and can run on a polished
non-hardened shaft. A familiar EV application was the Currie scooter.
* For the ETEK one could do any of the following:
* Get an ETEK without the keyed shaft, if possible.
* Turn the shaft down to remove the keyway.
* Weld up the key slot and turn the shaft to the original diameter.
* Fit a sleeve, optionally with a key, to the shaft. This will
probably jack the shaft size up to at least an inch and a quarter
which will limit the minimum sprocket size.
My choice, and what I'm going to do with mine, is to turn the shaft
down to remove the keyway AND to give me the option of lower tooth
counts. I'll probably go down to a half inch. I'm going to try to
mount the ETEK in the lathe and turn the shaft using the ETEK itself
to rotate the shaft.
In my testing with small EVs, mostly 2 and three wheel scooters, the
one-way freewheel clutch provides much more range extension than
regen. The reason is that the EV is in motion much more than it is
braking. With the freewheel, one can blip the throttle every so
often, like kicking a spinning top to keep it spinning, and otherwise
coast. I can almost double the range of my dual motor Currie by using
this method over holding a steady throttle.
John
On Thu, 21 Jul 2005 06:27:14 +0000, Jeff Shanab
<[EMAIL PROTECTED]> wrote:
>I would b pleasently surprized if the bicycle freewheel held up under
>the conditions the etek could produce. First they get part of they're
>strenth by always loading in double shear, and secondly there is a
>guarranty that the torque will drop off as rpm climbs. The etek may be
>able to continue to produce torque as the rpm climbs and I think they
>will wear quickly. The moutain bike single speed freewheels are indeed
>a stronger beast. What is the intended application?
>
---
John De Armond
See my website for my current email address
http://www.johngsbbq.com
Cleveland, Occupied TN
--- End Message ---
--- Begin Message ---
On 7/21/05, Stu or Jan <[EMAIL PROTECTED]> wrote:
> I am sure glad that you wrote that coasting is 'more better' than regen in
> an EV.
It isn't though.
A bicycle has a freewheel so you can give your legs a rest going down
hills and so on.
A scooter with a tiny, highly geared high speed motor, and a lack of
need for regen, might also benefit.
But for almost any other EV you can think of, it's completely wrong to
think that a freewheel will improve efficiency, since in a well
designed system the motor and transmission losses will only be a tiny
fraction of the overall friction and windage of the vehicle. And,
you'd lose the benefit of regen.
--- End Message ---
