Your vehicle
There are a lot of variables that affect each vehicle’s charging speed. When a battery is more depleted, the charging speed is typically faster. However, batteries don’t like to charge quickly when they’re too hot or too cold, so charging may be slower in extreme temperatures.
Different vehicle manufacturers design different batteries. And because the battery is usually the single most expensive “thing” inside a vehicle, it’s in everyone’s best interest to maximize the battery’s longevity, health, and safety. As a result, when a vehicle charges, the vehicle decides the power it draws from the charger in a way that maximizes longevity.
The charging system
Different electric vehicles have different capacities for charging speeds; charging stations also have different capacities, and the maximum rate of your charging session is determined by whichever is lower, the capability of the car or the charger. For example, a 50 kW capable EV would not charge any faster at a 350 kW station. Also, it is worth noting that higher capable vehicles can charge at lower capable stations, they are just limited to what the station can provide.
Outside temperature
Electric vehicle batteries don't like to be too hot or too cold. The charging of a battery generates heat (check your mobile phone when its charging), and the battery management system will protect a battery from overheating, so when the battery gets too hot the battery management system will slow down charging (and if the ambient temperature is high or you've been driving your EV for a long time then this might happen earlier as the battery temperature is already elevated).
