Improvements to the following components are deemed
essential for the future success of such an E-bike:
Over-Current Protection: During an accidental short-circuit
of the super-cap bank, the time response of the thermal fuse
proved inadequate. It is highly recommended that active overcurrent
protection be employed to allow for a faster response
time under fault conditions.
Charge Balancing: To prevent the possible over-charging
of individual super-capacitors, the super-cap bank voltage was
de-rated from 78V to 70V. As a result of this trade-off, the
total energy storage potential reduced from 74 kJ to 60 kJ. A
charge balancing circuit, such as those described in [16] would
allow the charging of the super-cap bank to its full potential
without running the risk of over-charging.
Regenerative Brake Lever: Whilst this worked effectively,
the lack of tactile feedback that a typical cyclist is accustomed
to whilst squeezing the brake lever may result in the mechanical
failure of the internal potentiometer when squeezed
too hard. A spring-loaded lever with a mechanical end-stop
is recommended to provide the tactile feedback and prevent
over-extension respectively.
Rapid Charger Interface: The super-cap bank was charged
directly from the rapid charger via polarised connectors. For
the envisaged campus commuter concept, it is proposed that
a split core transformer be used, with one half of the core
located inside the E-bike’s chassis and the corresponding other
half mounted on the bicycle stand at the charging station.
Tracking and Management of E-bike Fleet: With the addition
of a GPS and suitable communication module, the
whereabouts of the campus’ fleet could be tracked for management
purposes. For security purposes, using the GPS data,
the operational area of the E-bikes may be confined to campus
use only.