The reasons why you should recharge a battery are numerous. Maybe the car has stood still for some time at very low temperatures during the winter or used only rarely and for short distances.
The alternator may take some time to recharge the battery to the optimal level.
In addition, alternators are often unable to fully recharge the batteries, even during long journeys. As a result, the battery may need to be recharged regularly. By recharging the battery before winter, the risk that the car does not start in the coldest temperatures is significantly reduced.