Apple's notebook battery's don't charge if your % is 95 or higher when you plug it in. If you plug it in at 94, or 90, or 83, or anything less than any of those, it will charge up to 100%, but if you plug it in at 95, 96, 97, 98, 99 or 100, it doesn't charge because it doesn't need to. Prolongs the life of the battery.