Nissan Leaf: Lost Battery CapacityEnlarge Photo
Perry also declined to comment on independent tests conducted by electric-car advocate and Leaf owner Tony Williams, which took place in Phoenix recently and appeared to show range loss comparable to the indicated capacity loss in 12 Leafs tested.
"I understand what he was trying to do," Perry told Green Car Reports, "but it's hard to comment because we weren't there."
A further issue, Perry said, the battery capacity meter in the Leaf dashboard errs on the conservative side.
Thus, he said, a loss of three of the 12 capacity bars doesn't translate to exactly a 25-percent loss of capacity. In fact, not all the bars represent equal fractions of capacity.
This had previously been discussed by Andy Palmer, Nissan's executive vice president, who alluded to capacity-loss reports as stemming from a faulty battery level display.
Perry wouldn't specify what proportion of pack loss those three bars did represent, saying it could vary with each car's use.
The company would have to dig into its data on each individual pack to get those individual figures for each Leaf, he said.
Communicating with owners
While the Leaf batteries are behaving as the company expected, Perry admitted the challenge may be that the battery capacity losses may not have been what the owners of those electric cars expected.
Our analogy for battery capacity might be something like tire wear: The more miles you put on your tires, the more they wear.
Nissan Americas requires each buyer of a new Nissan Leaf electric car to sign a disclosure form in which the new owner acknowledges that battery capacity will decline over time.
The form also suggests ways the owner can maximize battery life.
Goodwill at risk
And that may be the real issue here.
"This ceased to be a technical issue a while ago, and has long been a goodwill issue," said electric-car advocate Chelsea Sexton, "based in what the drivers perceive as a lack of adequate communication."
And, she continued, if Nissan takes a position that 'there's still nothing wrong with your cars," that message is "unlikely to go over any better than it did the last time they said it."
On the other hand, electric-car advocate Mark Larsen takes a more nuanced view, decrying the angry tone adopted by some of the Leaf owners.
Your mileage may vary?
After analyzing the 12-car independent test data published by the owners, Larsen suggests that, in essence, "your mileage may vary."
His conclusion is that the Arizona heat affects "what data the capacity gauges are gleaning from the pack, but not the capacities themselves, according to miles driven."
This all indicates that there's likely to be much more to come on this story. Stay tuned.