This work describes the methodology and used data to analyze the effects of charging infrastructure on service depot of Battery Electric Trucks (BETs), to quantify its potential flexibility and discuss pros and cons of Electric Vehicle Supply Equipment (EVSE) with minimized charging power. The BET will be charged on their service depot during shift change, over night or other off-duty periods. This leads to heavy load on the corresponding network infrastructure but also offers the opportunity to provide flexibility for the energy system. Quantifying the load is done by analyzing existing BET data of uncontrolled and managed charging operations and enriching it with scenario simulations. Real world data from heavy duty refuse collection vehicles as well as logistic long-haul and short distance trucks is used. The analysis quantifies flexibility potentials of service depots, which can be used to reduce the impact on infrastructure and to optimize charging costs. A short literature review is provided for contextualization. The endeavors take place in a German city.