When a Nissan dealer services an all-electric Nissan Leaf, the garage’s diagnostic computer produces a Battery Information Sheet that can give the owner a an at-a-glance assessment of how healthy the battery is in his or her Leaf. 

But with several dozen Leaf owners, mainly in warmer states, reporting a loss in battery capacity--many within their first year of ownership--is it worth asking your dealer for a Battery Information Sheet when the battery capacity drops?

Does a formal Battery Information Sheet give you more information to explain why your Leaf has lost its first capacity bar? Or can it help you prevent premature loss of capacity?

It appears that the current BIS printout is missing some key historic information on battery conditions.

What it is

Produced automatically by the computer hardware used to service the Nissan Leaf, the BIS formally records the current state of health of a Leaf battery pack. 

As well as listing current battery capacity, it also uses your Leaf’s charging and use logs to construct an advice section which analyses past use and offers suggestions to maximize future battery life.

What it tells you

Nissan Leaf Battery Health Report

Nissan Leaf Battery Health Report

Alongside the current battery capacity, the BIS rates your historical Leaf use and care under four key categories:

  • Frequent use of quick charging
  • Frequent charging
  • Too much electric consumption while driving
  • Long term parking with a high state of charge

In each case, the system gives you a score, from one (poor) to five (excellent) stars, as well as a recommendation to help you improve on your score. 

What it doesn’t tell you

While the BIS tells you that its advice “can help to minimize the ongoing impact on your Leaf Li-ion battery, which can affect your battery’s total capacity over its lifetime,” it doesn’t display any analysis related to battery or ambient temperature.

So far, since most cases of battery capacity loss are occurring in warmer states, we think it may omit what appears to be the biggest factor in battery aging. 

Perfect score, but...

In fact, one of our readers sent us a BIS recorded on his Leaf by the local dealer after it lost its first battery capacity light. 

Based in Phoenix, Arizona, the owner’s BIS rated his historical use as being excellent in all four categories, and gave no advice on how to improve his battery care. 

Nevertheless, his battery capacity had dropped to 85 percent or less of its original capacity when new. 

“I took my car to Nissan Service today and got a perfect score on their battery ratings and was told that the loss is ‘normal’”, he told us in a recent communication.

“I spoke to the tech and showed him the service manual that the loss of one bar is a 15-percent loss and then showed him the disclosure statement indicating 80-percent battery capacity is expected after five years.”

The response he received wasn’t very helpful. 

2011 Nissan Leaf Software Update

2011 Nissan Leaf Software Update

“He said according to his information, this rate of loss was again normal, and that he had been seeing a lot of Leafs coming in like that,” we were told. 

Useful or not?

If customers who get perfect scores on their BIS are still suffering battery capacity loss less than a year after buying a brand new Leaf, you’d be forgiven for thinking that obtaining a BIS isn’t worth it.

However, unless you know that you’ll get a perfect score in all categories, we think it’s still worth asking for one from your dealer, especially if you’re worried that you’re not looking after your Leaf properly. 

Bear in mind however, that the current BIS does not monitor or report on battery temperature, something that seems to be one of the biggest contributors to battery aging. 


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