I have a brand new M3 from Dec 21, 2020. The sales girl told me I should only charge my car when it is down to 60%. I work at home and only drive to shopping. So every couple days my battery down to 60%. But on a YouTube video, somebody said you should charge your M3 every night. It does lose 2-4% at night without charging. So who is right for thennew battery of M3 for its best capacity?