I believe you are not fully informed... The alternator is not charging when idling, at stoplights or when at rest. The reason is to save gasoline. With all the electronics, Air-conditioning running directly off the battery instead of the alternator constantly recharging, you need to be aware of the differences and adjust your habits.
Hmmm, nope you are way off. Alternator output is proportional to engine rpm regardless of whether the vehicle is moving or at rest. At idle, the alternator is still providing current, however, it does charge slower. Whether the battery is charging or discharging depends on other electrical loads on the car and whether the sum of those loads exceeds what the alternator is currently providing. If the alt is putting out more that the loads, it is charging the battery, otherwise, the battery is discharging.
Battery dies after a few days of sitting
in Sixth Generation Legacy (2015 -2019 )
Posted
Hmmm, nope you are way off. Alternator output is proportional to engine rpm regardless of whether the vehicle is moving or at rest. At idle, the alternator is still providing current, however, it does charge slower. Whether the battery is charging or discharging depends on other electrical loads on the car and whether the sum of those loads exceeds what the alternator is currently providing. If the alt is putting out more that the loads, it is charging the battery, otherwise, the battery is discharging.