After the purchase of an EV, EV owners generally have doubts & misconceptions about the Vehicle Charging time. EV Charging time can vary due to multiple factors, these factors are discussed here.
Factors That Impact the EV Charging Time:
Battery size: EVs are equipped with different battery capacities (measured in kWh) ranging from 26kWh to 107kWh. If it is charged with an AC charger (3.3KW/7.4KW/11KW/22KW), then it will need more hours to charge. If 30kWh battery capacity is charged with a 3.3KW AC portable EV charger, then it will take approx. 9-10 hrs. to charge from 10% to 100%. The same battery if it is charged with a 60KW DC fast charger then will take < 1 hr. to full charge.
On-Board AC Charger Capacity: How much of a charge can a vehicle accept at once? For AC charging, the vehicle’s maximum charge rate is static, so it won’t save time by charging the battery at a more powerful charging station. If 7.4KW On-Board AC Charger equipped vehicle is charged with 22KW Charger, then the vehicle will only accept the charging current as per the 7.4KW capacity of the on-board charger. In this scenario, a 22KW charger will be oversized and will not be useful for speeding up the charging. EV won’t charge any faster than 7.4kW.
The Power of Charging Station: Charging time depends on the maximum charging rate of the charging station used. For example, the 58kWh Battery capacity charging time differs with 30KW/60KW/120KW Charging stations. EV Car can charge with DC voltage as per charging station’s maximum power rate.
Battery empty or full: If the Battery is at a 20% charged state, then it will take a longer time to charge. When the Battery charge state is 75% then it will take less time than in the earlier cases.
Battery Cells Voltage & temperature balancing: When the Battery charge state is reached 80%-90%, then BMS will accept a small level of charging current, the BMS slows down the charging & the charging current is used for balancing the Li-Ion all cell’s voltage & temperatures level to equality. After 90% charge state, it will take more time for charging. It is done to increase the life of the Battery &
to avoid Overcharging.
The ambient Temperature: Lower/Higher ambient temperature can lengthen the charging time. High temperatures can affect the electric car’s thermal management systems, affecting its efficiency. In Hot conditions, the EV Car’s Battery Management System (BMS) is used to curtail the level of charging current for safeguarding battery health. It increases the charging time.
Other issues: If the charger Hardware & Software nuisance malfunction, then it will take a longer time to connect the vehicle to the charger. Secondly, if the charging Gun is not properly connected to the vehicle, then, in this case, charging will not start. If there is a connectivity issue due to Internet Network failure, then the vehicle will take time to connect to the charger through the Mobile application. If there is a Grounding/Earthing issue in this case also the vehicle will not connect to the charger which creates problems with charging.
Moreover, EV car OEMs are having certain charging-specific guidelines that must be followed stepwise, lapses in guidelines/procedure adherence will create troubles in connecting the vehicle to the charger resulting in delayed charging.