Development of a Pay-As-You-Go Battery-Charging System for Electric Mobility in Nairobi, Kenya

The adoption of electric mobility in Nairobi is limited by high upfront costs, insufficient charging infrastructure, and uncertainties related to battery usage and financing (Oginga Martins, 2025). Pay-as-you-go (PAYG) models offer a promising approach to reduce financial barriers by linking energy access to incremental payments. However, the technical implementation of such systems requires reliable integration of payment platforms, software infrastructure, and physical hardware (Barry & Creti, 2020). This work presents the development of a PAYG battery charging system for electric two wheelers in collaboration with eWAKA. The system integrates a frontend interface, a Python-based backend, and a mobile payment function, enabling charging processes to be activated and controlled. The payment functionality was successfully implemented using the Daraja API, allowing to trigger charging sessions and the backend automatically terminate them once the purchased energy was consumed. The system was developed iteratively and tested in a controlled environment. Two different approaches to enabling charging were investigated. A hardware-based solution for e-bikes was implemented as a prototype, demonstrating that charging control can be achieved independently of existing battery systems. In parallel, an API-based solution for e-motorbikes was developed, utilizing communication capabilities of smart batteries to enable direct control of charging without additional hardware. The results show that both approaches are technically feasible, but differ significantly in terms of scalability and system complexity. While the hardware-based solution offers flexibility, it requires further development for large-scale deployment. The API-based approach provides a more efficient and cost-effective solution but introduces dependencies on battery manufacturers and external systems. Overall, this work demonstrates the potential of PAYG charging systems to support the adoption of electric mobility in Nairobi and highlights the importance of system integration, scalability, and reliable communication for successful implementation.