Chelsea Sexton, founder of the Lightning Rod Foundation, a co-founder of Plug In America, and star of Who Killed the Electric Car, recently sat down with Andy Palmer, executive vice president of Nissan, to discuss the Nissan Leaf and its battery degradation crisis in Arizona. You can watch the 16-minute video below, but here's the gist.

The interview starts with Sexton asking about the standards used to determine the degradation of the battery. Palmer said Nissan's assumptions during the design process were that the battery pack needed to have 80 percent capacity left after five years of normal usage, and after 10 years, it would be 70 percent. Some Leafs would be doing better and some worse than that, based on driving conditions over the years. Nissan figured there were four main variables that would affect those assumptions:
  1. Speed and type of driving you do – if you're always going at highway speeds, there will be more degradation.
  2. Frequent use of fast charging – Nissan recommends no more than once per day.
  3. Mileage on the vehicle – with 12,500 per year being the assumed average in Nissan's testing.
  4. What the temperature extremes are – both cold and hot.
As for the Phoenix situation, Palmer said that Nissan has collected data from 400 Leafs sold in Arizona. On average, Arizona drivers are doing about 7,500 miles per year. Given the other factors in play in Arizona, Palmer said that if we project the average Leaf battery life after five years there, it will be at 76 percent state of health, when the average should be 80. And this is driving an average of 5,000 fewer miles per year.

Then there's the question of transparency. Early on, Nissan made a decision to place a state of health meter on the gauge in order to let the customer know the state of health of the battery to add a sense of security. The irony is that it's had the opposite effect, adding anxiety for some drivers. There's now a mismatch from what drivers expected and what they've experienced, Sexton said, and some want new packs.

When Nissan originally developed the Leaf, the company couldn't imagine a scenario where the customer pays to replace the battery, Palmer said. When someone leases the car, Nissan takes all the risk for the car and battery. For those who purchased the car, there's an eight-year warranty plan. Nissan designed the battery so that replacement can be done module by module, keeping costs down. So, how much will it cost them to replace the entire pack?


Nissan never thought there would be customers, who after driving the car for a period of time, would want to restore the battery health up to 100 percent and maybe even buy a new pack. Thus, Nissan never set a price for a replacement battery pack. Nissan knows what a pack costs in a new car, but never assumed a full-on replacement would come to pass. Instead, Nissan assumed fixes would be done through replacing modules.

If some customers want to replace the battery pack at a certain point, Palmer said, Nissan will find a way to sell a fresh battery back to them. Nissan is asking for help from the Leaf's advisory panel on how to do it – what the price would be, what infrastructure is needed and whether it's practical. Sexton said that was fair enough, and we agree.

Sexton asked if there will be an upgrade path for early Leaf owners who want a next-generation battery when it improves in new Leafs. Theoretically, yes, Palmer said, but the issue is backward compatibility. Nissan wants to do that at the cell level instead of the module level.

Sexton's last question was about a different issue: the blasted "accept and deny" question that pops up on the screen. Will it ever go away? Well, that's due to living in a litigious society, Palmer said, and privacy laws require acceptance every time the driver starts the car. You can thank the lawyers for that.

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