Originally Posted by ChrisKaos
I'd like to see some evidence for this. It's true that LiPos should be kept stored at around those percentages, but so long as you're using them, then there's nothing wrong with fully charging them.
In fact, by charging them more frequently, you are damaging the cells. More frequent charging than is necessary can be harmful.
Actually, I meant LiOn, not LiPo, but even so, lithium battery lifespan is a complex subject. Every time you charge it you reduce its lifespace. Sitting new in its original box reduces its lifespan. Buying a spare lithium battery is not useful because when your first battery goes dead, the spare is nearly dead as well. Fast battery chargers (one hour or less) like the kindles use typically skip stage two of the lithium charge cycle and go ready (green LED) at 70% capacity. They may continue to trickle charge to full capacity, but this can reduce lifespan due to metallic lithium plating. Batteries rated for long life (military and medical applications) are specified with a lower operating (full charge) voltage for the same chemistry. The lower charge voltage increases the lifespan. But for consumer devices, it is more common to give a full topping charge to the higher specified voltage, and just let the battery have a shorter lifespan. This is why cellphone batteries have such a short lifespan (to make each charge last longer). You can read more about this from many different websites...