Université de Yaoundé I

The degradation of electric vehicle (EV) batteries in tropical environments is poorly understood in the literature. This study aims to experimentally characterize the degradation of EV lithium-ion batteries and to assess the influence of climatic factors (temperature, humidity, dust) and local driving conditions (road quality, mileage) in the tropical environment of Cameroon. Our contribution lies in providing unique empirical data, obtained from real-world monitoring, specifically adapted for sub-Saharan environments and incorporating variables often overlooked. An on-board experimental device was developed on a test EV, integrating Arduino-compatible sensors (DHT22 for temperature/humidity, Sharp GP2Y1010AU0F for dust, ADXL345 for road quality, Neo-6M for mileage) and an existing battery monitoring module (BMS) (an LTC6811-based data acquisition system for cell voltage and a shunt for current) for continuous collection of battery parameters over two years (SoH, SoC, internal temperature, and internal resistance). The analysis focused on trends in SoH and internal resistance and their correlations with environmental and driving parameters. The results show a gradual degradation of SoH and capacity, as well as an increase in internal resistance. High temperatures, humidity, and dust, as well as poor road quality, are directly correlated with an acceleration of this degradation. In conclusion, tropical climatic conditions and local driving characteristics have a significant impact on the aging of EV batteries. These findings are crucial for the development of adapted BMS and the optimization of EV performance in similar environmental contexts, promoting sustainable mobility in Africa. • First comprehensive analysis of electric vehicle battery degradation in a tropical climate (Cameroon), offering unique insights into real-world performance. • Internal battery temperatures reached critical peaks (up to 55°C), strongly correlating (0.83) with increased internal resistance and accelerated degradation. • Significant thermal inertia was observed between ambient and internal battery temperatures, highlighting sustained thermal stress in hot environments. • Dust accumulation and high ambient humidity are identified as major environmental stressors, exacerbating battery degradation. • Multicollinearity was identified among key environmental variables, necessitating careful statistical consideration for accurate interpretation of individual parameter effects .

The escalating impact of climate change on agriculture in sub-Saharan Africa particularly endangers smallholder farmers reliant on natural resources for their livelihoods. Local perceptions play a crucial role in crafting effective adaptation strategies, yet few studies have explored the socio-economic elements shaping these perceptions in agro-ecological transition regions like Mbangassina in Cameroon. This research intends to fill this void. A mixed-methods strategy (quantitative surveys, qualitative interviews, and climate data assessment) was used. The findings indicate that 97.2% of farmers have noticed climate variations over the past thirty years, defined by reduced rainfall and increasing temperatures, as corroborated by meteorological records. The analysis reveals that older age and greater annual income positively reinforce the awareness of climate change, whereas extensive farming experience lessens it. Access to microcredit and being female are linked to a diminished perception, while community involvement and residential stability boost it. In response, farmers are implementing strategies such as utilizing short-cycle varieties, altering planting dates (early or late sowing), and diversifying crops. However, the uptake of these practices varies considerably across villages. In light of these findings, adaptation policies must be differentiated: they should aim to build capacity for youth and women (who are less informed about the changes), enhance financial inclusion through suitable credit products, support community organizations, and secure land tenure to promote long-term investments. This research therefore emphasizes the necessity for customized approaches, grounded in local socio-economic realities, to translate climate awareness into resilient adaptive capacity.