Nissan publishes open letter to Leaf owners over battery capacity loss

Yesterday was National Plug-in Day (NPID), a nationwide celebration of electric vehicles organized by Plug-in America, the Electric Auto Association and the Sierra Club. On the eve of NPID, or more succinctly, on the eve of thousands of Nissan Leaf owners gathering face-face across the country, Nissan released an open letter concerning the battery capacity loss issue that is worrying Leaf owners. The latest letter is again an attempt to quell the fears of Leaf owners, but it appears that Leaf owners are starting to have a deaf ear for Nissan's communications on this matter.

The issue is that some Nissan Leaf owners are noticing diminished battery capacity. This lost capacity is measured in one of two ways: 1) when the Leaf is fully charged, the dashboard State of Charge will show fewer "bars" of capacity; 2) 3rd party instrumentation gauges which display battery charge in GID's. Diminished battery capacity generally means the Leaf has a shorter driving range, making it less useful as a car. Primarily the affected Leaf's are in hot climates like the Phoenix area, leading many to think the cause of battery capacity loss is the heat and blaming Nissan's choice to not have a cooling system. Nissan, in their responses in June, last week, and below, are focusing on the Phoenix and Arizona based Leaf owners. Not liking Nissan's responses, a large group of Nissan Leaf owners staged a massive test of Leaf battery capacity in Phoenix a bit over a week ago, and managed to measure some of the capacity loss. In the meantime, Coda Automotive is making the case for the thermal management system their engineers chose to use.

Nissan's latest letter (replicated below) reveals more about the company's investigation than had been revealed last week, but "more" is a relative term because there are many details left wanting.

When Nissan says "You are truly our best ambassadors to the next generation of passionate EV drivers," we should think back to July when it was beginning to sink in that Nissan Leaf sales this year were starting to be dismal. At that time loyal Leaf owners were brainstorming Nissan Leaf marketing ideas on the MyNissanLeaf forum. Today the MNL forum has a lot of worry about this battery capacity loss issue.

When Nissan says they identified seven Leaf owners in Phoenix, do we know for sure the issue is this limited? Browsing the MNL forum, there are many who do not live in hot climates who are suffering from diminished battery capacity. An example is Tony Williams who drove on the BC2BC trip (Baja California to British Columbia) in June, but there are others. The NPID event I attended in Silicon Valley had more than one person reporting diminished battery pack capacity. While these people have put a lot of miles on their Leaf's, Silicon Valley has neither hot nor cold weather.

Nissan says they "measured capacity, and conducted voltage testing on individual battery cells" which sounds nice, but what does it mean. Having built battery packs for electric motorcycles and cars, I can say that this cannot be done just by measuring the voltage of the battery pack and cells. Instead this test has to be a dynamic measurement over time, because lithium battery cells have largely the same voltage except when fully charged and fully discharged . To perform this test, Nissan's engineers will have had to completely charge and discharge each pack at least once to measure the amp-hours that can be pulled out, graphing the voltage the whole time.

Going by the discussion on MNL, Leaf owners are hearing Nissan say "nothing to see here, move along." What Nissan says in this letter is that the packs they tested are behaving as expected given the usage pattern of each individual vehicle. However, 2 years ago Nissan's promise in marketing literature was "80% remaining capacity after 5 years" without explaining nuances like the ambient temperature or the distance the car has been driven. It is a fair assumption for a Leaf owner to read "80% remaining capacity after 5 years" and think battery degradation will occur linearly over a set period of time. Nissan is trying to make the case, after the fact, in a way that looks suspicious to Leaf owners (going by discussion on MNL), that there are additional technical factors which were not disclosed to Leaf owners.

Indeed one of the MNL members suggested these disclosures by Nissan would help: 1. Produce an "ideal" speed/range chart that lets you know how fast/far you can travel on a single charge in a new car. All new cars should be able to match these numbers at a minimum. The data in NTB11-076a is not good enough, but it's a good start. 2. Provide guidelines on how capacity will be reduced over the warranty period based on where you live assuming typical usage (used as daily commuter, parked in sunny parking log, parked in garage, etc). 3. Provide guidelines on how tweaking usage habits may improve or reduce capacity loss over time. How does calendar life change when using 80% vs 100% charging? How does calendar life change when averaging 3.5 mi/kWh vs 4.5 mi/kWh?

Perhaps the most important part of this letter is the selection of Chelsea Sexton to lead an independent advisory board. Sexton has a long history of electric vehicle advocacy work, and was the co-star of the movie Who Killed the Electric Car (the 'leading man' was GM's EV1). Perhaps the role of this advisory board will be to keep Nissan honest. The discussion on the MNL forum today is full of distrust of Nissan, and the extreme nuances of Nissan's communication is not going down well with the Leaf owners. Sexton's history includes standing up to the automakers as an independent voice.

Additionally, a Nissan marketing communications leader, Jeff Kuhlman, Head of Global Communications for Nissan Motor Co., joined the MNL forum to directly talk with the community. His resume includes a long stint with GM where he worked on the EV1. He recognizes "it’s clear that [Nissan has] much work to do on the communications front," that "[Nissan has] been too silent on what Nissan is working on, what we think the future looks like, and what innovations are coming." The move is risky because, as Kuhlman notes, when a manufacturer directly engages the customer base in an "enthusiast forum" that "too often such efforts, while noble, [come] off as spin" and manufacturers prefer to monitor enthusiast forums and post responses through an "owned channel" like a youtube account or facebook page. Kuhlman recognizes "that the discussions will often be tough" but promises to bring Nissan people to the MNL forum for a direct conversation.

Source: OPEN LETTER TO THE LEAF COMMUNITY
From Carla Bailo

Happy eve of National Plug In Day. We’re excited that Nissan LEAF owners are gathering nationally tomorrow to celebrate zero-emission motoring, and appreciate that so many of you are sharing your enthusiasm with others. You are truly our best ambassadors to the next generation of passionate EV drivers.

We also want to update you, the LEAF community, on our findings regarding battery capacity loss concerns expressed by a number of owners in the Phoenix market. Nissan takes customer concerns seriously, and we know many of you have been interested to hear what we’ve learned in our thorough investigation, and what it all means.

We identified seven LEAF owners in the Phoenix area who had reported concerns with their vehicles. With their agreement we brought the cars to Nissan’s Arizona test facility, where we removed the batteries for evaluation, measured capacity, and conducted voltage testing on individual battery cells. These tests were diagnostic only; no modifications were performed to the battery packs themselves.

After returning cars to their owners, we analyzed the results of our tests, with specific emphasis on the rate of actual capacity loss for each vehicle. Our goals were simple: to determine 1) if there were any defects in materials or workmanship in the individual batteries or vehicle systems; 2) if the batteries were performing to specification; and 3)their performance relative to the global LEAF population.

This week, we will meet with these LEAF owners to share our findings on their individual vehicles. In the mean time, we can report the following overall findings:

• The Nissan LEAFs inspected in Arizona are operating to specification and their battery capacity loss over time is consistent with their usage and operating environment. No battery defects were found.
• A small number of Nissan LEAF owners in Arizona are experiencing a greater than average battery capacity loss due to their unique usage cycle, which includes operating mileages that are higher than average in a high-temperature environment over a short period of time.

While we understand that some LEAF owners are concerned about battery capacity loss, we want all owners to remember that all battery-electric vehicles – and all lithium-ion batteries – demonstrate capacity loss over time. So while your LEAF may have been able to travel a certain distance or more on a charge when new, its range will decrease as the battery ages, miles accumulate and gradual capacity loss occurs. This loss in capacity will occur most rapidly in the early part of your battery’s life, but the rate should decrease over time. Information on gradual battery capacity loss is available in the paperwork that was delivered with your vehicle, in the owner’s manual and on the many vehicle resources available at http://www.nissanusa.com/leaf-electric-car/.

It is also important to put the scope of these concerns in perspective. Globally, there are more than 38,000 Nissan LEAFs on the road that have travelled more than 100 million zero-emission miles, and we expect these vehicles, in normal operating conditions, to retain 80 percent of battery capacity after five years. As each user’s operating characteristics are unique and many factors impact battery capacity, we can expect some vehicles to have greater than 80 percent capacity at five years, and some vehicles to have less. In Arizona, we have approximately 450 LEAFs on the road. Based on actual vehicle data, we project the average vehicle in that market to have battery capacity of 76 percent after five years – or a few percentage points lower than the global estimate. Some vehicles in Arizona will be above this average, and some below. Factors that may account for this differential include extreme heat, high speed, high annual mileage and charging method and frequency of the Nissan LEAFs in the Phoenix market.

We at Nissan stand by our product, and we also stand by our customers. Recently, we’ve asked Chelsea Sexton, a passionate advanced technology advocate, to convene an independent global advisory board. Members would be selected by Chelsea, not Nissan, and they would recommend their own mandate, but our hope is that they would hold up a mirror to us and help us to be more open and approachable in our communication and to advise us on our strategy. We should have more information on the advisory board in a few weeks.

As we work with individual owners to ensure their satisfaction, we are appreciative of your continued support of both the Nissan LEAF and the electric vehicle movement, overall. We look forward to continuing our dialogue here in the MyNissanLEAF forum and within the Nissan LEAF community.

Best Regards,
Carla Bailo
Senior Vice President, Research & Development – Nissan Americas