"If we want to preserve battery performance is quick charge safe?" Many observers are concerned that quick charging will harm the battery pack, while both Nissan and Mitsubishi claim it is safe. Another questioner asked "The user manual recommends quick charging only once a day. Do the following cases affect the battery health in different ways? A) Quick charging the LEAF four times in one day, followed by three days without quick charging. B) Quick charging the LEAF once a day in four days?" This reminds me of a high school friend who wanted to give up Lent for Lent, reasoning that Lent was the time you give up things that are good for you, that Lent is supposedly good for you, and therefore... uh..
Mark Perry: "Absolutely! The LEAF is capable of quick charging multiple times per day. Our battery management systems always protects the battery from risk. Charging rates will slow down if for some reason temperatures get out of the 'normal' range."
Mark Perry: "We updated the owners manual. Multiple quick charges are ok. The BMS protects the battery in all cases. If temperatures get outside normal range the charging rates simply slow down." What he's saying is the potential for harm is if the battery pack temperature rises too high during fast charge. It's not the act of fast charging that can cause damage, but the temperature increases.
http://www.eetimes.com/design/automotiv ... ogy-basics
I only searched for that today because A Leaf owner today told me while he was in for his service he was given a battery report saying he still has 100% capacity after 24,000 kms. That's when he said they told him to fast charge as much as he wants!