joeriv
Well-known member
I found two lab studies which may shed some light on Nissan's battery degradation and conditions for maximizing battery life:
https://avt.inl.gov/sites/default/files/pdf/vehiclebatteries/FastChargeEffects.pdf
This study follows four Nissan Leafs over a 50,000 mile test, two cars which were DCFC charged and two which were L2 charged in Phoenix AZ. The cars were run 6 days a week almost to turtle and then immediately charged to full. Ambient temps were what you would expect for Phoenix and contributed greatly to battery loss - marginally worse would have been Death Valley. Average battery temps during charging ranged from 73F to 105F.
The average of 3 different measures for battery capacity remaining after 50,000 miles showed 74.5% for L2 charging and 69.8% for DCFC charging. These results are absolutely worst case conditions for the Leaf.
http://batteryuniversity.com/en/learn/article/how_to_prolong_lithium_based_batteries/subscribe_thx
This study on prolonging lithium battery life verified what many of us believe:
1. Heat is the worst enemy for lithium battery life.
2. Deep cycling hastens battery degradation.
One conclusion of this study was that charging between 65-75% State of Charge (SOC) offered the longest life cycle, maybe not realistic for EV batteries, but instructive nonetheless.
My takeaway is that keeping my Leaf battery between 35 to 75% SOC at moderate ambient temps will add a lot to battery life. Thankfully temps in CT are not anywhere near Phoenix levels during the summer.
No doubt there are some cases that are more extreme under less trying conditions - that's why there are two tails on a normal distribution curve; some will show incredible longevity and some will degrade faster than average. That's just the nature of the beast.
https://avt.inl.gov/sites/default/files/pdf/vehiclebatteries/FastChargeEffects.pdf
This study follows four Nissan Leafs over a 50,000 mile test, two cars which were DCFC charged and two which were L2 charged in Phoenix AZ. The cars were run 6 days a week almost to turtle and then immediately charged to full. Ambient temps were what you would expect for Phoenix and contributed greatly to battery loss - marginally worse would have been Death Valley. Average battery temps during charging ranged from 73F to 105F.
The average of 3 different measures for battery capacity remaining after 50,000 miles showed 74.5% for L2 charging and 69.8% for DCFC charging. These results are absolutely worst case conditions for the Leaf.
http://batteryuniversity.com/en/learn/article/how_to_prolong_lithium_based_batteries/subscribe_thx
This study on prolonging lithium battery life verified what many of us believe:
1. Heat is the worst enemy for lithium battery life.
2. Deep cycling hastens battery degradation.
One conclusion of this study was that charging between 65-75% State of Charge (SOC) offered the longest life cycle, maybe not realistic for EV batteries, but instructive nonetheless.
My takeaway is that keeping my Leaf battery between 35 to 75% SOC at moderate ambient temps will add a lot to battery life. Thankfully temps in CT are not anywhere near Phoenix levels during the summer.
No doubt there are some cases that are more extreme under less trying conditions - that's why there are two tails on a normal distribution curve; some will show incredible longevity and some will degrade faster than average. That's just the nature of the beast.