scottf200 said:
Several reasons and some threads on GM-Volt but a main one is that I'm almost through my 3rd summer (late Aug'13 @24K EV miles) with my 2011 Volt and it seems my EV range in the morning is slightly higher (1-3 miles so like 48 consistently) than the 2011 and 2012 summer. After my first several months with the the car I learned how to drive it efficiently. I would fully expect it to be dropping slowly and slower than the LEAFs because it is much better managed. I've been watching various threads here at MNL where people are using the Android based tools to literally watch their battery degrade weekly even in good climate areas. Chemically they are supposed to be similar.
Thanks for the update, Scott!
I find it interesting that your EV miles appears to be going UP! That's a bit counterintuitive to me, too. One possibility that jumps to mind is that perhaps GM is adjusting the available SOC based on battery "health" versus just battery capacity. What I mean is that they may be offering up a bit more capacity to make up for increases in resistance. But since you guys in the Volt can (assumedly) see how much available capacity you have, I would expect that would be obvious.
Another possibility is that it has been cooler here this summer. Perhaps the same is true in Chicago? Maybe that has an effect such as less energy used for climate control, etc?
We're only on our second summer in the 2011 demo LEAF we purchased in Mar 2012 and I will say we have made a major adjustment from last summer: we charge only enough to return home with about 30%-or-so SOC. That's not as hard to achieve as it sounds, particularly given the slow charging rate. I also am finding that I am setting new economy records using our other car, an HCH with an 11.5 YO battery pack. All that to say that our driving style is still changing (improving) after about a year and a half.
With the smaller available capacity in the Volt, there is less battery babying that can be done in a Volt other than simply charging right before you leave. It sounds like you drive your entire available charge every morning. Is that the case? If so, then your battery has the benefit of spending nearly all of its existence in the 20% SOC range. That, along with the climate where you live, should help you to achieve long battery life.
May our batteries live long and prosper!