Multirotors can usually operate with a larger battery than recommended for longer flight times but slightly less performance. However, there is a point of diminishing returns at which increasing the battery size will just make a drone so heavy that it uses more power to stay in the air than the added battery size provides.
How do I know when a battery will be too big and won't provide significantly more flight time? Is there some way to calculate the diminishing returns of increasing the battery size for a freestyle quadcopter?
My goal is to get the longest flight time that I can while only losing the upper-end performance which I don't use anyways.