Your Alternator Is Not A ChargerYes, you read that right. An alternator is designed to MAINTAIN your car battery, not recharge it from a deeply discharged state. Its designed to run at only 35-50% of its fully rated output. When you use your cars alternator to recharge a dead battery, you force it to run at nearly 100% of its rated capacity and that overheats the alternator and dramatically shortens its life.
This was the opinion also of https://hyp.is/YNQwwlF0Ee206UcS3HYLnA/www.reddit.com/r/Cartalk/comments/aoks7b/how_much_idling_needed_after_jump_start_to/
but are they misinformed?