The ideal state of charge for a lithium battery is 50%. So charging between 20% and 80% would significantly lengthen battery life. If you wanted to completely o

The ideal state of charge for a lithium battery is 50%. So charging between 20% and 80% would significantly lengthen battery life. If you wanted to completely optimize for low battery degradation you'd charge between like 49% and 51% and only have a few minutes of usage, but that kind of defeats the point of keeping a lot of battery capacity.