That is established for those in severe heat no babying of the battery will save them. Heat is the number 1 enemy.klapauzius wrote:Bigger battery, same chemistry, will degrade as fast in the heat as a smaller one? I thought it was established, that heat beats cycle losses by wide margin?dhanson865 wrote:Don't you think the two are intertwined?Weatherman wrote: One more summer of battery degradation should do it.
No matter what the new-car range is, a 20%+ loss in capacity in a year and a half makes it a no-deal for me. Nissan needs to fix the degradation problem, first, then consider offering more battery capacity.
It is also established that if you keep the battery perfectly at the same temperature at all times that depth of charge (time spent below and above certain state of charges) age the battery unrelated to heat.
1. Keep the battery as cool as possible (oops no active cooling on the Leaf you really can't control this and still drive the car*)
2. Avoid leaving the car fully charged (how high is too high is a valid question but the more time at or above level x equals y degradation)
3. Avoid fully depleting the battery (how low is too low is a valid question but the more time at or below level x equals y degradation)
*But the "I thought it was established" was based on the old battery chemistry with the old capacity and the old charging rates. Change each of these by any significant amount and you might find that the amount of degradation by heat and state of charge are both reduced.
Heat is the enemy but heat isn't just the temperature outside your car. Your battery gets hotter as it is charged. Your battery gets hotter as you drive (discharging the battery).
If you change the size of the battery pack you won't change the temperature outside the car but you will change the amount of heat** generated by charging at a certain rate and driving at a certain speed. If that extra heat is the straw that breaks the camels back having a larger pack might decrease degradation by a significant amount, if the battery chemistry is a poor fit for the ambient temps then the bigger battery just ages fast no matter how big or small the pack.
** technically the amount of heat is lowered by some amount and the rest is spread around a larger pack, giving a lower temperature with a similar amount of added heat.
Is a multivariate equation you can't take a rule of thumb from the 2011 leaf with chemistry A 24KW pack or a 2013 leaf with chemistry B/C 24KW pack and say that it applies the same to a Leaf of the future with chemistry D 48KW pack.
Heat will still be the number 1 enemy but we don't know how much of the country will be in the advanced degradation zone for a battery pack that doesn't exist yet. I'm just saying we should at least entertain the possibility that for a some portion of the country a larger battery pack could make degradation due to heat a non issue.