Colloquium announcement

Faculty of Engineering Technology

Department Design, Production and Management
Master programme Sustainable Energy Technology

As part of his / her masterassignment

Pablo Javier Gaete Haller

will hold a speech entitled:




In the past years, electric bicycles have become one of the most popular and convenient alternatives for motorized vehicles as they offered decreasing prices and increased drive ranges, offering competitive trip speed in high-traffic zones. Currently, limited research exists in the field of electric bikes (e-bikes), which focus is mainly on health, mobility and safety impact. However, the technical performance of e-bikes is poorly understood.

The aim of this research is therefore to obtain technical data of e-bikes that are charged by PV systems, with an interest in the daily trip patterns by e-bike users and the related energy consumption by the battery.  For this purpose, a sensor kit was developed to measure key variables of e-bikes batteries. The kit comprises sensors for the measurement of voltage, current and temperature and a data storage device. GPS coordinates can also be obtained to analyze the trip’s patterns such as traveled distances and travel speed. The sensor kit can be installed into the bicycle structure to measure and store data during use of e-bikes

Initial field tests show a correct performance of the sensor kit. Subsequently, the main features of the e-bike’s batteries during the charge and discharge process have been measured and analyzed for several e-bikes that have been involved in a field trial. GPS data recorded the ride’s parameters for a period of one week per user. For instance, GPS coordinates, show a daily traveled distance of 8.6 km and a maximum speed of 16 km/h. 

Since lithium batteries are the common technology for EVs today, a model based on Li-cells was developed to check the main battery variables that were measured such as the voltage, the charge current and the capacity. For the model, ten cells were connected in series leading to a nominal 36 Volts battery at 2.5 Amperes.

For the simulated battery,  a total capacity of 10.8 Ah (411.6 Wh) was calculated.  When comparing simulated conditions with measured data,  obtained capacities were 100.7%, 98.3% and 95.7% respectively due to the different temperature condition for partial charging testing. For a  full discharge battery,  the final capacity reaches a 94.1% of expected full capacity. The instantaneous power needed to charge the battery also presents small variations.  Maximum variation was a 5.5% lower power than simulated.