> Was looking at this during the week
>
> http://secure.oatleyelectronics.com//product_info.php?cPath=53&products_id=776&osCsid=2eb2f62c9972b3db4044319f2a4605af
>
> or K271 at http://www.oatleyelectronics.com/
>
> Bicycle front wheel + 24V 200W electric motor + bits
>
> Has anyone had any experience with this sort of drive ?
>
> Something I'd consider if it could be used as a generator to
> re-charge the batteries. During downhills for example
>
> Don't know the efficiency but I guess it needs around 10A from
> a pair of 12V SLA, and those would be a fair old weight, maybe
> 2kg each for a 12V 6A
>
> Any idea how a motor like that would perform as a generator ?
>
> 50%, 25% ?
>
> Joe
>
> *
> *
> **********
> Quality PIC programmers
> http://www.embedinc.com/products/index.htm
>
I wonder if it's worthwhile. For around the local shops perhaps,
although that's not much of an effort anyway. Without being able
to recharge the batteries en route, I can imagine on a long trip
you would end up carting around 10's of kilos of flat batteries
and a useless dragging motor
The Crystalyte system for example ranges from 50 - 80lbs.
Good grief, I weigh only 112. Don't know what the 200W
Oatley motor weighs
I suppose if the weight of the bike could be lessened that would
help. Hmmm, how much does a leg weigh ? And the therefore
unnecessary pedal......
> Was looking at this during the week
>
>
> http://secure.oatleyelectronics.com//product_info.php?cPath=53&products_id=776&osCsid=2eb2f62c9972b3db4044319f2a4605af
>
> or K271 at http://www.oatleyelectronics.com/
>
> Bicycle front wheel + 24V 200W electric motor + bits
>
> Has anyone had any experience with this sort of drive ?
>
> Something I'd consider if it could be used as a generator to
> re-charge the batteries. During downhills for example
>
> Don't know the efficiency but I guess it needs around 10A from
> a pair of 12V SLA, and those would be a fair old weight, maybe
> 2kg each for a 12V 6A
>
> Any idea how a motor like that would perform as a generator ?
>
> 50%, 25% ?
>
> Joe
>
> *
> *
> **********
> Quality PIC programmers
> http://www.embedinc.com/products/index.htm
>
> 200W? It is like 1/4 hp, is not it? Not sure how well it would
> drive any sort of vehicle?
I think it's more like an assist. The Crystalyte and Estelle are a
couple of kW, but the downside of those is the weight of batteries
needed. Both those suppliers are not forthcoming with range figures,
which I expect would be fairly meagre, saying in effect only that
the harder you run the motor the lower the range. The minimum
you'd want to run them is to cover the extra weight. The temptation
might be to use the motor more than necessary, and then you get
to thinking about "necessary"
Even if you could fit one of those high wattage systems in NZ, over
300W = paperwork
200W is barely worth the extra weight of motor + batteries.
You'd do better getting lighter, thinner, wheels and tires which would give
you less resistance to begin with.
I had a hub motor for a while. I think it claimed 350 watts. It was kind of
fun but it added so much weight that it wasn't worth it and it didn't help
noticeably at all on hills.
-
Martin
> Was looking at this during the week
>
>
> http://secure.oatleyelectronics.com//product_info.php?cPath=53&products_id=776&osCsid=2eb2f62c9972b3db4044319f2a4605af
>
> or K271 at http://www.oatleyelectronics.com/
>
> Bicycle front wheel + 24V 200W electric motor + bits
>
> Has anyone had any experience with this sort of drive ?
>
> Something I'd consider if it could be used as a generator to
> re-charge the batteries. During downhills for example
>
> Don't know the efficiency but I guess it needs around 10A from
> a pair of 12V SLA, and those would be a fair old weight, maybe
> 2kg each for a 12V 6A
>
> Any idea how a motor like that would perform as a generator ?
>
> 50%, 25% ?
>
> Joe
>
> *
> *
> **********
> Quality PIC programmers
> http://www.embedinc.com/products/index.htm
>
Mine was a little different; what was offered at the time.
Works great. Quite hilly around here, too. 160-200 mpg, depending
on gearing, who's riding it, & so on.
Comments: I started off with a 36-spoke rear wheel. After I switched
to 48 I never broke another spoke (Velocity Deep-V rim).
I'm a big guy. YMMV.
I've got an 1:2 drive out of the gearbox - It'll climb a 7% grade @ 10 mph,
without protest. Top speed 17 mph - IMO, enough, considering bicycle
brakes...
I ended up with 2 front wheel folding wire baskets, & 1 in the rear on
the left side. Very handy
I live in the mountains and looked into getting a 3-wheel electric bike. Three wheels because when going up hill slowly it's hard to balance. See the paragraph on "Drive Methods" at: http://www.prc68.com/I/3WRBikes.shtml#DM
where the following methods are presented with patent links:
Tire Friction Drive
Drive Through Pedal Shaft
Direct Drive to Rear Wheel
Wheel Hub Motor
Jack Shaft Drive to Rear Wheel
It would be a good idea to try out whatever drive method you are considering on the roads where it will be used.
Thanks. There are plenty of bright ideas for getting power to
the wheel, but not for getting power to the batteries. A huge
leap would be to make the system self-sufficient. Considering
inefficiencies and energy balances it's likely to be difficult. At
least perhaps until high-temperature superconductors are more
available
> It would be a good idea to try out whatever drive method you
> are considering on the roads where it will be used
NZ in general is pretty bumpy, based as it is on fault lines and
volcanoes. I can't go far in any direction from here without
facing more than one significant hill. What helps me get around
is patience. Take something to listen to and be cool
Not sure I fancy a recumbent. Always thought they are an
invitation to be squished
I recall seeing only one personally, they are not common
What do you mean by self-sufficient? Of course, some energy input will
always be needed (even if it is only human power). I'm guessing that
you mean a system which can efficiently absorb all of the regeneration
from braking and deliver it again when power is needed.
>> http://www.prc68.com/I/3WRBikes.shtml#DM
>
> Thanks. There are plenty of bright ideas for getting power to
> the wheel, but not for getting power to the batteries. A huge
> leap would be to make the system self-sufficient. Considering
> inefficiencies and energy balances it's likely to be difficult. At
> least perhaps until high-temperature superconductors are more
> available
>
>> It would be a good idea to try out whatever drive method you
>> are considering on the roads where it will be used
>
> NZ in general is pretty bumpy, based as it is on fault lines and
> volcanoes. I can't go far in any direction from here without
> facing more than one significant hill. What helps me get around
> is patience. Take something to listen to and be cool
>
> Not sure I fancy a recumbent. Always thought they are an
> invitation to be squished
>
> I recall seeing only one personally, they are not common
>
> Joe
>
> *
> *
> **********
> Quality PIC programmers
> http://www.embedinc.com/products/index.htm
Super-capacitors are getting better - Promising for
regenerative recovery apps. Electric bikes will look
a lot better as Li secondary batteries get cheaper
> What do you mean by self-sufficient? Of course, some energy input
> will always be needed (even if it is only human power). I'm guessing
> that you mean a system which can efficiently absorb all of the
> regeneration from braking and deliver it again when power is needed
Yes. The disadvantage I'm seeing with some of these systems is that
the motor can't be used (or, rather, has not been designed) to convert
kinetic energy to charging energy, or even to just disengage the motor
to reduce pedalling effort, eg if it happens to be a permanent magnet
motor with significant cogging. I remember the bad old days of a tyre
dynamo. I suspect many of the motors are permanent magnet, as the
manufacturers advise about magnet corrosion. You might actually
expend more energy, for example if the batteries are drained early on,
depending on the terrain during the journey, based on the experience that
it's always easier to get current out of a battery than put it back in
> Super-capacitors are getting better - Promising for
> regenerative recovery apps. Electric bikes will look
> a lot better as Li secondary batteries get cheaper
That's the way it seems to me. Electric bikes are a good
idea but I don't think technology is quite there yet
You can make a dual alternator / motor that is essentially cogging
free - even with iron in rotor and stator..
If you use "ironless" construction for the stator you can get
essentially zero cogging as of right. This is realistically only
possible with rare earth magnets. You can get alternator efficiencies
over 90%.
Making a motor regenerate is not overly hard. But for best results
you'd want to smps convert it to the appropriate energy for battery
storage.
Battery charge rate is a significant consideration. No matter how
little power you expend when running , you want to be able to reduce
velocity at a "good" rate so power delivered is high. If you were
using a say 12V 7AH AH battery then even at say 10C charge you are
allowed 70 A x 12 V = 840 Watt = slightly over a HP. Consider how
rapidly 800 odd Watts would accelerate you and decide if you want to
decelerate no faster than that under braking.
I didn't think so.
Oh well.
(Some might say).
Lead acid is not too keen at very high charge rates although, properly
done it can tolerate higher curr4ents than usually claimed. LiFePO4 is
far more tolerant but so far is very very expensive compared. Overall
lifetime cost of ownership is lower than any other common battery but
capital cost is mny times larger.
My electric scooter uses regeneration for braking. If you take
your hand off the throttle it stops right now - I'm surprised it
does'nt have a seat belt...
The controller also limits coasting speed to 5 mph.
I can take the bus to the shopping center, circa 3 miles, 700
foot elevation gain (GPS), then coast back, arriving home with
an apparently fully charged battery.
I have an electric powered bicycle, I've had it a couple of years. It has a
250W 3-phase hub motor. As stated previously it really is an electric
assist, its not a lot of use up hills but it does help, on the flat it
manages 20mph without too much effort (I tweaked the speedlimiter). It came
with a lithium ion battery back which isn't particularly bulky or anywhere
near as heavy as SLA types. The bike itself is much heavier than a
conventional bicycle but there is no noticeable drag with the motor switched
off. Overall I am very happy with it even though I do live in a hilly area.
It is a Synergie Avanti if anyone wants to gargoyle it. The only real
annoyance is that the lights don't work with the motor off.
Cheers
James
> My electric scooter uses regeneration for braking.
.... I can take the bus to the shopping center, circa 3 miles, 700
foot elevation gain (GPS), then coast back, arriving home with
an apparently fully charged battery.
>/
700 foot fall x say 150 kg (alter as needed) = 700/3.28 m x 150 kg x
9.8 (g) =~ 313000 Ws ~= 87 Wh ~= 7.3 Ah at 12V.
That's at 100%.
Maybe 5 Ah delivered with suitable electronics
Energy same, current halves if 24V etc.
At 100% at 5 mph over 3 miles that's ~= 145 Watts mean or ~12 A at 12 V
On a say 40 Ah battery that's ~ C/3.5
That would be more than enough to cover 'running around' a shopping centre etc.
Possibly enough to overcharge a battery if not properly managed by the
controller.
clear.net.nz> wrote:
