The large-scale deployment of electric buses and trolleybuses in urban public transport requires advanced energy management strategies that consider operational constraints, power-grid interactions, and battery longevity. Digital Twin (DT) technology offers a promising framework to support such strategies, but it depends critically on high-quality real-time data from the physi-cal system. In this regard, this paper proposes a mobile data acquisition (mDAQ) system installed on electric vehicles as a key enabling layer for a Holistic Energy Management System (HEMS). This system collects syn-chronized multiparameter data in electrical, thermal, positional, and operational streams through IoT communication towards DT models that opti-mize charging schedules, energy flows, and preventive maintenance. Its ar-chitecture combines multiplexed sensing, floating differential measurement, Geographic Positioning System (GPS) synchronization, MQTT-based com-munication, and driver-oriented user interfaces. The proposed solution is po-sitioned within an integrated DT-based framework for urban e-mobility and can be deployed in a real public transport operator network.