Since I have driven the Mini-E for the past 15 months I thought I'd contribute my 2 cents to this discussion regarding battery temperature and its effect on range, performance, etc. Of course, the Mini-E is quite different from the Leaf in many respects, but a few things I thought might be useful to consider:
1) If the Mini-E battery temperature goes above 115F, regen is shut off and therefore affects range. In addition, max power is limited to avoid further overheating.
- Although I live in Southern California, getting to 115F happens pretty easily when you park in the San Gabriel Valley sun all day and then accelerate quickly home at 5pm.
- Shutting off regen never made complete sense to me, but I will say that when that 115F threshold is crossed, it makes one rather wary of what the car will do next.
2) I found that not only would I be concerned about range while driving the MiniE, I became obsessed with the battery temperature. I still am to this day. On warm summer nights, I park at home with the windows down. During the day, I park about a 5min walk away from work under a cluster of massive Chinese elm trees which haven't been trimmed in decades.
3) There is no question that low temperatures affect range more than anything else. Even here in Southern California, I found that a battery temp around 60F would reduce my typical range of 100 miles down to 80 miles (and lower if I really punched it). Reportedly, subzero temps in the East Coast actually made the cars dead and unusable at times.
To be honest, I began to feel that the battery temp issue along with the range issue was a deal-breaker for making EVs truly a possibility for the mass-market. I am VERY curious to see how the Leaf handles these issues in the real world. My basic impression is that the Leaf's battery chemistry is inherently superior to what the MiniE used and much less temperature-labile. But hey, I'm not battery engineer and I assume someone on the forum might have an idea about this? I haven't seen any long-term real-world test drives of the Leaf yet, but one would assume that this is exactly what Nissan has been doing for awhile. That being said -- Tesla's Model S is supposed to have a 'water-cooled' system for their batteries. The Leaf battery system doesn't sound very robust. Thoughts?