Nissan responds to Leaf owners worries about battery capacity loss
Over the last several weeks some Nissan Leaf owners in Phoenix have reported significant loss of battery pack capacity. The loss of capacity was much steeper than to be expected given the intended 8-10 year lifetime of the Leaf battery packs. Between the level of discussion, and recent news coverage, Nissan's Carla Bailo, senior vice president, Research and Development, sent an open letter to Nissan Leaf owners explaining the situation, and making it clear that Nissan is taking this seriously.
Generally speaking lithium ion batteries do not do well in hot weather, and of course Phoenix and many other cities are known for extremely hot weather. The heat wave this year of course exacerbates worries over the effects of heat on the battery pack. Unlike some of the other electric cars being made, the Nissan Leaf does not have a heating or cooling system on the battery pack leaving no protection against the heat. Nissan's engineers clearly felt it was safe to not have a cooling system, while engineers for other automakers felt otherwise.
A very long discussion thread on mynissanleaf.com identified a dozen or more Leaf owners in not just Phoenix, but other cities in the hot Southwest U.S. who have significant lost battery capacity, some to the tune of 15% capacity loss after one year of ownership. Nissan has repeatedly told Leaf owners to expect 20% capacity loss over 5 years, and clearly losing 15% in one year is a significant worry. According to the summary of the discussion thread, there is no correlation with car color, air conditioned garages, or several other conditions.
A week ago Leaf owners concerns were raised in several news reports including one here on TorqueNews (see Nissan Leaf owners in hot climates experiencing battery problems). As we noted then, this news could spook prospective Leaf owners and be a crushing blow to the Leaf, whose sales were already weak this year.
Carla Bailo's open letter acknowledges the discussion on mynissanleaf.com (and elsewhere) saying "The forum's discussion around battery capacity loss has reached a point where I feel it important to personally address what is being debated, to provide Nissan's viewpoint and, most importantly, to explain the actions we are taking to work with owners."
Bailo claims "only a handful" of battery capacity loss cases exist, and that Nissan is taking the issue seriously. She goes on to explain that "Battery capacity loss of the levels reported may be considered normal depending on the method and frequency of charging." This is a claim which some in the community will be very concerned over, because Nissan's battery warranty covers abnormal capacity loss, not "normal" capacity loss. Whether the capacity loss is normal for a given car depends on, according to Bailo, "the amount of electricity consumed during daily usage and a vehicle's mileage and age." In other words, Bailo implies that a car which is heavily used could see significant battery capacity loss. Typically the lifetime of a battery pack is measured in the number of deep discharge and recharge cycles, not in the calendar age of the pack.