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Inside EVs reports on independent testing of Nissan LEAFs and battery capacity loss

An independent test of Nissan LEAF battery capacity and range loss organized by Inside EV writer and LEAF owner Tony Williams has found significant battery capacity loss—and therefore range loss—in the EVs. In a post on the Inside EV site, Williams has compiled the data and published a report on the test.

The Nissan LEAF electric car was introduced to the world as a mass production vehicle during December 2010. Almost 40,000 have been sold around the world in the short time since then, with well over 10,000 sold in the USA. Unfortunately, a percentage of those USA cars that are operated in hot climates, such as Phoenix, Arizona, and the state of Texas, have experienced accelerated losses of the vehicle’s range autonomy, when compared to its performance when new. The phenomenon is not relegated solely to areas of extreme heat; many LEAFs now in moderate temperature areas of California have also experienced significant range autonomy reduction, however not yet to the extent of those cars exposed to Arizona and Texas heat.

When customers have complained, thus far Nissan has claimed that any reduction in range is “normal”, regardless of how much that capacity loss is. Battery issues that are covered under the warranty include “power” to accelerate, or a specific battery failure or abrupt change in the battery performance. Nissan specifically claims that they do not warranty capacity.

...Earlier this month, an Australian news agency reported that a Nissan Executive Vice President with specific experience with the LEAF, Mr. Andy Palmer, said that there is “no problem” with the LEAF battery, and that the any customer complaints were merely the result of instrument problems.

In response to this revelation, a group of twelve Nissan LEAFs were independently gathered on Saturday, September 15, 2012 in Phoenix to put this statement to an actual range test; driving a fully charged LEAF in controlled conditions to measure how far they could actually go. Any battery test (or allegation of good batteries) is meaningless if the car can’t actually do the job it was designed to do. In the USA, that job is advertised as traveling “100 miles” (161km), and even further, 200 kilometers (124 miles) in Japan. Clearly, if Nissan truly felt that the batteries were performing as designed for the customer cars they tested at Casa Grande in July, they could have simply verified that at the private, purpose built test track at their disposal there. The actual driving portion of the test would have taken about 90 minutes per car, but they chose not to. Four of the twelve cars in Saturday’s Phoenix area test were previously at the Casa Grande test facility in July.

...My car, Black782 and the BC2BC car, tested at about 89% of available battery capacity, and drove to 91% of available capacity. That’s within 2% between the two figures and a reasonable error. Other cars had HUGE differences between the instruments and the actual range performance. So, Andy Palmer was right…they have poor instruments. But, he was wrong about the batteries. It was sheer stupidity to tell this group of owners that the batteries are ok. A California study showed that about half the owners have post-graduate degrees, and many of those are in technical fields. A significant percentage have owned electric vehicles prior to the LEAF, and many, if not most of those who have traded their faulty LEAF have gotten another electric powered car, like the GM Volt, and like me, another LEAF.

Nissan – Renault chairman Carlos Ghosn announced Friday that 2013 LEAFs would have a new battery design. One has to wonder if this is merely public relations move to deflect from the current battery woes, or if a real new battery will emerge. Then, we have to wonder if they employed the same testing that the current batteries were exposed to. Nissan really needed to get the LEAF right the first time, and they did an absolutely incredible job overall. I tell everybody know that it’s a fantastic car with one fatal flaw.



An improved (liquid cooled) battery thermal management system may be required on all PHEVs/BEVs, specially for those used in very hot areas?

Electronic controls to limit charge/discharge rates within safer range may also help to avoid misuses or improved batteries promised on the 2013 model.

Second and third generations BEVs will certainly have ways to better protect the batteries.


Continual deep cycling, driving hard (high current) with the AC on, and fast charging could also cause faster performance decay in the batteries. Some, but not all, in Texas and AZ have decayed rapidly. So what's the difference? Why some and not others?

Nissan's response has not been good, but if our press is incapable of telling the facts without spin, wouldn't you expect everyone to try and avoid giving out information. By the way, our press is incapable of telling the facts without spin. They worry about ratings and readers and just how much they can make off of advertising. So, you should read every story as if it is intentional lies. That way you can find more truth.


This hurts EVs. From the start, less than a three digit, 100 mile, EPA range in a country thousands of miles across is marginal, despite <30 mile urban trip averages.

It could be critical that Nissan adds 40% more range quickly.

Dave R

What really hurts is that most people only feel comfortable going down to the first low battery warning and not much further - a point at which a less than 4 kWh remains usable and about 11-15 miles range remaining. Note that the first low battery warning always comes on at slightly less than 4 kWh remaining regardless of battery capacity reduction.

Add to that most people typically drive in a manner which matches the EPA rating of 73 miles range.

So when their LEAF is new, most people only drive about 60 miles comfortably.

Now factor in 20% capacity loss which reduces maximum range from 73 miles to 58 miles. Now you only have about 45 miles of range before range anxiety sets in. So while their battery pack has lost 20% capacity - in real life people have lost 25% usable capacity.

This will feel worse at end-of-life when the pack has lost 30% capacity - now you only have about 38 miles of range before the first low battery warning - and you've lost nearly 50% of your usable range.


It's no wonder that there are people in Phoenix who are complaining that their cars can barely drive 50 miles per charge.

Unfortunately - there's only 2 solutions and they appear to be expensive if this isn't a "gauge" problem as Andy Palmer of Nissan has suggested:

1. Fit thermal management to the car to minimize calendar losses.
2. Add a significant amount of capacity to the LEAF's pack - I'd suggest at least 20% to offset capacity losses down the road.

Neither of these will be easy or cheap to retrofit.

For pure EVs - it is going to be a big adjustment to get customers used to the fact that lithium batteries degrade. One possible solution would be to hide more of the pack's available capacity (perhaps unlockable by entering a special range mode like the one Tesla uses for infrequent use) when the car is new. This would at least give the appearance of more constant range availability for daily use and restricting maximum state-of-charge more will also help improve calendar life, too.

Dave R

Note regarding my previous post. It has incorrect calculatons - the percentages are low - usable capacity loss percentage should be about 4-5% higher than the respective total capacity loss. For example, losing almost 50% is not correct for the 30% capacity loss scenario - it's really about 35% loss of usable (39 usable vs 60 usable) - still exaggerated due to the fixed low-battery-warning level, but not as bad as what my initial bad calcs suggested.

Kit P

“I tell everybody know that it’s a fantastic car with one fatal flaw. ”

The doctor enters the waiting room and tells the anxious family that he is proud to report the surgery went perfectly. 'When can we see out mother?' 'Oh she died.'

BEV advocates may want to avoid independent testing as it make it much harder to be delusional. As see in the statements, it is not impossible to remain delusional.

Just for the record, it was a stupid test. Some of already know that battery performance degrades at high and low temperature.

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