Hello Larry,
This is a nice summary and I did not see any errors. I do have some
comments that I think need to be addressed. I also provided some of my
experiences with respect to electric bikes but I am sure you have run
across some of these experiences already.
One person I know rides a Currie Izip to and from work. Her main goal
is to get to work without having to take a shower. She loves her bike
for that ability and she rides on basically level ground with some small
hills. We are in the southeastern USA and just going to the mailbox in
the summer can produce the feeling that you need a shower. I can attest
to the ability of an electric bike to climb long hills without
generating heat stroke (but still need a shower).
I tried a geared bike and stripped a nylon(?) gear. The bike, motor,
lead acid pack and me weighed in over 300 pounds. That is a lot of
weight to put on the teeth of a nylon gear. I bought a "bearing puller"
to pull the two parts apart to get at the gear... If I had to do it
again, I would go with a non-geared bike. The bike I bought was a
conversion and used a heavier steel bike frame.
For an electric bike conversion, the gap between the forks has to be
wide enough to receive a wheel with a motor encased between the spokes.
If the gap is too narrow, bending the forks is not a good idea. Most
converters use a mountain bike frame.
Changing a flat on the motored wheel is problematic as you have to deal
with the motor cable. Some of the newer bikes have cable disconnects
near the hub. My conversion does not and I have to cut on plastic ties.
On one of the trails in the local area, I thought I was making great
progress until I was passed by several people on road bikes at twice my
speed. Still, no complaints as I was able to go the distance with a bit
to a lot of assist from the motor.
Your 15-25 pounds may be a little on the light side. A quick glance at
the Currie line up has their bikes at around 53 (w/o pedals) to 60
pounds. My son's "commuter" bike weighs in at 30 pounds. Also, the
electric bike frames tend to be sturdier (read heavier) to support the
extra weight and stresses. I would up your 15-25 pounds to maybe 20-30
pounds. (My bike weighs about 65+ pounds but it has a lead acid pack.)
You might also want to mention electric cargo bikes (Yuba Bikes, etc.).
I rode an electric Yuba cargo bike and was impressed with how it felt
more like a road bike when using the electric motor.
http://yubabikes.com/cargo-bikes/elboda/
>> So the motor only operates when you pedal <<
My understanding is that the "motor only operates **after** you begin
pedaling". I think the manufacturer's were working on this because of
the initial effort to begin pedaling was strenuous (especially uphill)
until the motor kicked in. The ideal was to have the motor kick in as
you started pedaling. Not sure of how much progress has been made in
that regard.
Hope this helps.
Peter
On 8/26/2014 1:38 PM, Larry Gales via EV wrote:
I am trying to interest the largest bicycle club in my area (Seattle), he
Cascade Bicycle Club, about the importance and future of electric bikes.
In July I wrote an article about the fun, practicality, and benefits of
e-bikes, and now I would like to provide information that would help them
purchase an e-bike or an e-bike kit. So I want to know if the information
that I give them is accurate. So if you see any errors in the presentation
below, let me know.
Thanks,,
Larry Gales,
Here is the article (limited to 600 words):
======================================================
In July I wrote an article in the "Courier" about the many advantages of
electric bikes, or e-bikes, and how they are becoming a mainstream form of
local transportation throughout Asia and Europe. I hope to encourage
people in this country to acquire e-bikes and so relieve us from the
problems caused by the near exclusive use of automobiles.
There are many aspects to consider when acquiring an e-bike:
o The method of purchase: buy a ready made e-bike or convert an
existing bike with a kit
o The odometer and battery state of charge display
o The power you need (typically 250 to 750 watts)
o The type and size of battery
o The type and location of the motor
o The wheel size compatible with an e-bike kit
o The weight of the e-bike, typically 15-25 lbs more than conventional
bikes, but note that with an e-bike, the weight only matters when
lift or carry it, so you can easily detach the battery, cutting the
additional weight to 8-12 lbs.
o The purchase cost and servicing of e-bikes
Here we consider only the type, control, and placement of the electric
motor in an e-bike.
o There are three main ways to control an e-bike motor:
- Pedelic: this multiplies the power you apply to the pedals,
typically by 25% to 300%. So the motor only operates when you
pedal
- Throttle: the motor starts when you press the throttle. You can
also pedal to add power or extend the range
- Both: many e-bikes provide both options
o There are two main types of e-bike motors:
- Mid-drive motor: this is a geared motor that drives the chain
wheel which in turns powers the chain that powers the rear wheel.
The main advantages are that the motor is isolated from the shock
and vibration of the wheel, and it operates in a way that is most
similar to the way a conventional bike works. However, it
requires frequent gear shifting which must be coordinated with the
motor controls
- Hub motor: this motor fits inside the wheel around the axle, and
is the most common e-bike motor. The main advantages
are that it greatly reduces the wear and tear on the
drive train as it powers the wheel directly, it usually eliminates
the need to shift (if the motor is sufficiently powerful), it
often enables regenerating braking which can restore
10-20% of the battery charge, and adds a 3rd braking option.
Note that hub motors mounted in the front wheel cannot use
pedelic control. There are two main types of hub motors:
* Gearless hub motor: this is powered by a ring of rare earth
magnets that are electronically switched on and off to turn
the wheel. It has no moving parts and lasts longer with less
(usually no) maintenance than geared motors, it is the
quietest of all motors, and enables regenerative braking.
The main disadvantages are that it is larger and
somewhat heavier for the same power as a geared motor, the
torque (needed for hill climbing) is about 20-30% less,
especially at very low speeds, for the same power rating as
a geared motor, and there may be a small amount of drag when
the motor is off.
* Geared hub motor: this uses planetary gears. It does not
cause any drag when the motor is off, has more torque and power
for a given weight than a gearless hub motor, but does not
(currently) allow regenerative braking. It is slightly noisier
than a gearless motor and requires more maintenance because it
has moving parts.
========================================================
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