mark13 wrote:I charge the leaf 100% every other day..I don t remember the salesmen ever saying to only charge at 80% to save the battery for a extended life..
I wouldn't pay attention to the salesmen. Nissan didn't name the 80% charge "Long Life Mode" for nothing. It's right there in the manual. However, we don't know exactly how much this will prolong battery life.
I believe I can shed some light on this question.
1) One of the Nissan Engineers that I met questioned why I wasn't using the 80% charge feature, given that I have a short commute. He claimed that Nissan's testing shows that only charging to 80% will double the battery pack life on average, when compared to fully charging the battery pack.
This was the first time I'd heard a quantitative
comparison like this (as opposed to "80% will give you longer battery life" without letting you know if it's just 5% more life, in which case I'd never use it). I did some more research on the subject, and found that other than deep discharge or very rapid charging, one of the worst things you can do to a lithium battery is to fully charge it, and then leave it fully charged at high temperature. Evidently, crystal structures will form that inhibit the normal chemical reactions from taking place in some spots on the battery, thereby reducing its ability to charge and discharge in those areas.
2) I had been 100% charging every other day to prevent "memory" effects from occurring, which are a problem with NiCd batteries. The engineer told me this is unnecessary; this type of battery does not develop memory if you just use it around the middle of its range. In fact, that is desirable.
3) I told him how I was going to have a L1 and L2 charger, and only use L2 when I absolutely needed it, since I wanted to be "gentle" and keep the battery cool when recharging to minimize stress. The engineer told me that although L3 charging will definitely heat things up and reduce battery life, L2 is not much different than L1, since in both cases you're charging the pack up over many hours. I had requested a feature where you could limit charging current to reduce the thermal load on the battery pack - they told me this was not worthwhile, at least at the 3.3kW level that L2 has available now.
As a result of the conversations, I changed to plugging in every night, using the timer set to 80% max, and stopped worrying about what L2 charging will do to long-term battery life. I have encouraged Nissan to publish more quantitative details of their life testing, but until then, I hope this helps answer some of the questions on this thread.