USA Today Story on hot/cold weather range

[Stanton]

I usually don't quote USA Today, but I think the following data lends support to the decision Nissan must have struggled with during the Leaf design phase (and one we've debated here on the forum for YEARS):

"AAA conducted a simulation to measure the driving range of three fully-electric vehicles – a 2013 Nissan Leaf, a 2012 Mitsubishi iMIEV and a 2014 Ford Focus Electric Vehicle – in cold, moderate and hot weather. It tested the vehicles for city driving to mimic stop-and-go traffic between December and January, fully charging each EV, and then "driving" each on a dynamometer in a climate-controlled room until the battery was fully exhausted.

Brannon said two of the vehicles, the Mitsubishi and the Ford, were equipped with dedicated management of the battery temperature. "We were expecting that difference would yield differences in the optimal range of the vehicles in extreme temperatures," he said. "It did not."

The likely reason: There's only once source of power in an electric vehicle – the battery. If battery power is being used to heat or cool the battery, it takes power away from the vehicle's range, he said.

The average electric vehicle battery range for each full charge in AAA's test was 105 miles at 75 degrees Fahrenheit. That dropped 57% to 43 miles when the temperature was held steady at 20 degrees. Warm temperatures were not as stressful but still delivered a lower average of 69 miles per full charge at 95 degrees, AAA said."'

 

[adric22]

The average electric vehicle battery range for each full charge in AAA's test was 105 miles at 75 degrees Fahrenheit. That dropped 57% to 43 miles when the temperature was held steady at 20 degrees. Warm temperatures were not as stressful but still delivered a lower average of 69 miles per full charge at 95 degrees, AAA said."'

That seems like a drastic change. Were they running climate control?

And I thought the thermal management was just for long-term protection of the battery, not for range. Their tests seem to confirm that.

 

[KJD]

http://www.usatoday.com/story/money/business/2014/03/20/cold-sharply-cuts-range-of-electric-vehicles/6622979/" onclick="window.open(this.href);return false;

They had to be running the heater full blast for that much of a drop. One could argue however that is what most people would do, so it may be valid to test the car that way.

"For most Americans, where a round-trip commute is less than 40 miles, the range of the vehicle will not be a problem," he said. "However, if the temperature dips down and you want to take a drive to grandma's house, you might want to think about a charging station along the way."

This would also underscore the need to have charge stations everywhere and available 24x7. Around here the charge stations are few and far between.

 

[TomT]

I think they may have missed the point that many of us learned a long time ago... TMS is more about protecting the battery and preventing degradation than it is about increasing range...

Brannon said two of the vehicles, the Mitsubishi and the Ford, were equipped with dedicated management of the battery temperature. "We were expecting that difference would yield differences in the optimal range of the vehicles in extreme temperatures," he said. "It did not."

 

[Stanton]

I think they may have missed the point that many of us learned a long time ago... TMS is more about protecting the battery and preventing degradation than it is about increasing range...

However (and this is why the debate rages on), if the "hot pack" battery displays degradation characteristics Nissan originally intended/simulated, then that point (again) becomes moot.

 

[adric22]

However (and this is why the debate rages on), if the "hot pack" battery displays degradation characteristics Nissan originally intended/simulated, then that point (again) becomes moot.

Indeed. We are absolutely thrilled with the range we are now getting in our new Leaf compared to our 2011 model. If that range would still be available 3 or 4 years from now, that would make a HUGE difference. I used to say that the Leaf needed 25% to 50% more range. And it still does for many people. But I think the current range is actually plenty as long as that range did not degrade and were still available in cold weather.

 

[mkjayakumar]

^^^ This.

My new 2014 has plenty of range as of now, I have no range anxiety. But that will all change when the summer hits and the battery capacity drops steadily week after week and month after month, and at the end of the 2nd summer I will be hypermiling and looking for back roads to get around.

If only Nissan can guarantee 280 Gids at the end of the 5th summer, then I could go evangelize this car with my whole heart. With the current degradation pattern you may need to start with 400 Gids or around 30+ kWh to end with 21 kWh after 5 years.