EMT Electric Bicycle Projects
We have been asked to look at a project enabling electric powered bicycles to climb steep hills even when the rider has impaired pedalling ability.
The legal maximum power for electric bicycles in the UK is 250 watts continuous power and for tricycles and tandems 300 watts
We are working on providing maximum torque within these limits. Speed is not a major issue providing it is high enough to maintain balance.
So far we have built a prototype drive onto an old tandem as a feasibility study. We are pleased our concept worked with regard to gearing and drive through the main chain and a hub gear.
Our next move is to trial hub motors in various configurations.
These come from a number of different manufacturers but with common features. They mainly have a reduction gear within the hub and the ratio is fixed. However they are available in different windings with different torque characteristics. We are experimenting with different windings and different custom controllers to maximize the hill climbing capabilities while maintaining an acceptable speed. We are also working on overall weight reduction.
The bicycles being trialled range from a Brompton folder:
A Pashley tricycle:
and a number of commonly available more conventional bikes.
We are also trialling a number of different battery types.