leafwing said:
spike09 said:
Lack of active cooling is an oversimplification.
Why isn't every LEAF driven in hot weather climates losing range at relatively equal rates? Even ones with similar driving and charging patterns are not showing similar capacity loss.
It is not oversimplification; it is the main reason why some cars experiencing early capacity loss. There could be other minor reasons.
Not all the cars are at the same age, same mileage, same charging and driving patterns . The lack of active cooling in hot climates accelerates the degradation of the battery. We did not have this problem last summer when most of the packs were fresh. Next summer you will see more of it.
Or, all the cars with early capacity loss are equipped with defective batteries. After the Casa Grande test, Nissan said all the tested batteries are performing within specifications.
The high and constant heat of Arizona can affect the Leaf battery in other was, that active cooling might not even solve. Which is why the claims of "no active cooling = problems" is considered an oversimplification.
The active cooling for EVs (including the Chevy Volt) only runs when either (1) plugged in, or (2) driving....
1) EVs today are typically only plugged in after 8pm when outside temperatures are much lower than daytime highs. The Volt's active thermal management systems (TMS) only runs if the temps are above 104F when plugged in. They are unplugged shortly after sunrise so the driver can drive to work.
2) Driving only accounts for about 1 or maybe 2 hours a day. And really, only the afternoon drive from work to home will experience high temps.
So, TMS doesn't run very often for a normal commuter.
Now, most EV drivers cannot charge at work. So the Leaf (and Volt) sits all day, under a hot sun, for 6 - 8 hours.. with temps exceeding 100F during the summer. http://tinyurl.com/Leaf-BadBatteryMap" onclick="window.open(this.href);return false;
Active thermal management cannot save the battery from this, since it won't be able to run during this time.
**The Volt may not be showing similar degradation because of various factors that include a MUCH higher reserve/buffer of unused capacity. GM did this because longevity of the pack was more important that Electric range since the Volt has a gas engine.**
According to the wiki page:
http://www.mynissanleaf.com/wiki/index.php?title=Battery_Capacity_Loss" onclick="window.open(this.href);return false;
Mean Temperatures over overall, is a main factor in reducing calendar life as we are seeing. Not so much the short term spikes in temperatures during driving... but the long term high temps of parking on blacktop during the work day.
I think that active cooling may mitigate the capacity loss somewhat, but it certainly won't be a silver bullet that avoids the calamity we are seeing in Arizona, Texas and SoCal.