My experience with folding electric bikes for urban transportation

Electric cars are a significant step toward a sustainable way of life.
Automobiles of any type, however, are too large and use too many
resources to be our only main form of transportation and are not
scalable to the entire world population.

Bicycles, on the other hand, appear to be the most energy efficient
form of transportation known to man or, apparently, nature. But
bicycles have some severe limitations. Imagine that it is a dark and
stormy night, you have a sore leg, a pounding headache, are dead
tired, and you have to bicycle 5 miles, mainly uphill, to the
drugstore -- that is real hardship.

Now imagine that you have a lightweight folding electric bicycle that
operates in 3 modes: pedal only, motor assisted pedal with different
assist levels, and motor power only. You first put on a lightweight
electric vest, followed by a lightweight goretex raincoat and your
bike helmet.

You plug you vest into the battery on the bike, select the right
temperature, turn on a bright LED headlight, and simply sit and steer
and ride to the drug store, warm and dry, and with little more effort
than driving a car, but using 50-100 times less energy and materials,
and with far less impact on traffic congestion and parking space.

Or imagine commuting 35 miles to work by riding your bike 3-5 miles to
the most optimal bus stop. When you get there, you fold up your bike,
stick it in a bag, and carry it on the Bus when it arrives. You have
now made mass transit more accessible, it that bus lines don't have to
lie within 5 blocks of your house, and made it more efficient in that
the Bus need stop every 3-5 miles instead of every 3-5 blocks. And now
a Bus can carry 30-40 bicycles instead of just two.

So the vision I have is that folding eBikes can play a significant
role in urban/suburban transportation in the near future. To test
this out I bought a Dahon folding bike and then had a BIONX 350 watt
motor and 350 WH battery added to it. Here is the result of my
experience with this setup:

o The power is fully adequate: I can pedal up steep hills at
16-17 MPH w/o much effort using the highest (300%) assist
level. For that matter, I can use the throttle, and with zero
effort (no pedaling) at all, climb the steep hill at 14 MPH.

o The range is adequate: 3 times a week I make a 22 mile round
trip from my house to the UW. 10 miles of that each way is on
the rather flat Burke-Gilman trail, where I use a 75% assist,
but there is a 3/4 mile stretch to my house that consist of
steep hills where I use the full 300% assist. Each round trip
consumes about 40% of the battery charge, leaving more than
half left.

For another example, I put it through the most severe test I
could find in my neighborhood: I went up and down that 3/4
mile stretch that consists almost exclusively of steep hills
multiple times for a distance of 5.5 miles, at 14-15 MPH, but
letting the electric bike do ALL the work w/o any pedaling,
and it still used less than 1/2 of the battery charge.

o It folds just as easily w/ the BIONX kit as the original
folding bike, except for one plug which I easily unhook.

o Even w/ the battery in place, it is almost as compact to fold
as the original bike, and with the battery removed it is
exactly the same as the original bike.

However, there are two major limitations that prevent it from meeting
my goals for widely used transportation:

o The throttle only works in an all-or-nothing mode: if you
press it you get full power, and cannot control your speed.
Given the sophistication of the motor assist which controls the
motor based on a combination of your effort and the gear you
are in, I find this very surprising. I see this as a problem
that could easily be overcome.

o The bike, at 46 lbs (the original bike was 27 lbs), is too
heavy to fold up and put on a Bus. If I remove the battery (8
lbs), and stick it in my backpack, the remaining 38 lbs is a
lot more manageable, but still too heavy. However, if this
bike were designed from scratch as an electric bike, rather
than a jerry-rigged add-on, it would probably loose about 3
lbs, and if it were made of carbon fiber, which would not be
expensive if mass produced, it would lose another 5 lbs,
making it 38 and 30 lbs, respectively, w/ and w/o battery
and would be acceptable.

There are also some minor problems that could be easily resolved:

o All folding components are held by pressure, and it takes a
lot of force to adjust the seat height. It would be much
better if slots were used to adjust things, especially
the seat height

o It is somewhat tricky to simultaneously adjust the seat
height while aligning the seat direction parallel to the
frame.

o The battery is somewhat tricky to remove and install

So, in conclusion, I believe that the technology for a practical
folding electric bike that that can play a significant role in
urban/transportation, both individually, and in conjunction with mass
transit, is now available, but that no manufacturer has yet put all
the pieces together .

-- Larry Gales

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