RWatkins said:
Curious how much of a performance hit you get in winter. My situation here in north Idaho is similar to yours with an insulated garage, mountain inclines (not as much as yours), snow, packed snow, slush and ice in that order.
We're still working to sell our house before moving forward on a Leaf, but it's good to get real world experience regarding winter driving before buying. The garage ranges from 55-60 degrees most the time with occasional drops to 40-50 degrees. Our longest time out in the cold weather is 5-6 hours.
Thanks in advance for your input.
First, "performance" could be either efficiency (miles/kWh) or range. Efficiency affects range, as does battery capacity. Battery capacity is affected by temperature and losses due to degradation (age, heat, cycles).
• With your garage situation you will lose relatively little range due to battery temperature. Even if your car is stored at 50ºF the battery will be somewhat warmer than that due to charging. I'll guess it would be 54º. If you look at
Tony Williams' Range Chart, footnote 3 suggests a loss of about 4% battery capacity at that temperature versus 70º.
• The hit to range from cold air depends on speed. Below 35 mph it would be fairly small. At freeway speeds it would be significant. If cold air caused a 12% increase in drag and air resistance was 60% of the power used to move the car, then driving efficiency and range would be decreased by about 7% on dry pavement. You can get an idea of drag numbers due to cold from my
Air density and temperature thread.
• Hills are also a problem because you don't get back all the energy going downhill that you put in going uphill. In footnote 1 Tony suggests 1.5 kWh per 1000 feet elevation gain and perhaps half that recovered for elevation loss. However, bear in mind that at very cold battery temperatures, <10ºF, regen tends to be limited, which reduces the amount of energy that can be recaptured (you wouldn't ordinarily see battery temperatures this low with your usage pattern). If you can coast safely you can turn some of that potential energy into kinetic energy, although it is also subject to drag losses.
• Using the heater, even the new heat pump on the 2013 SV/SL models, will be a big hit to efficiency and range. However, heater use can be mitigated by preheating while plugged-in, defogging the windshield with unheated air when practical, and using the seat and steering wheel heaters to reduce the need for cabin heat
*. And being dressed appropriately for winter, of course.
•
The biggest hit to range would be driving on snow, in all its myriad forms. That's hard to quantify because it is so variable. A related efficiency loss would be if you use snow tires: they have a lot more rolling resistance than the stock low rolling resistance tires. Drop your numbers by 5-10% if using snow tires on dry pavement. By the way, the LEAF makes a fine snow car due to front wheel drive, a fairly heavy weight with even distribution, and a low center of gravity.
FWIW, my mileage calculations over the last two winters:
Bear in mind that much of my mileage is at slower speeds and 60 mph is the maximum I ever drive (no freeways or multi-lane highways here), I drive a lot of steep hills by necessity, and I'm a pretty good "hypermiler". Also, I drive relatively little on snow here in sunny Colorado because I either wait until it melts, or it is plowed and sanded, or I take my Jeep. So my numbers will look better than those of someone who drives a lot in real winter conditions or someone who drives at high speeds in very cold weather.
In short, "it's complicated". The range of a LEAF in winter might be reduced by one third to a half of the range in summer over the same routes. [By the way, my parents lived next to Lake Coeur d'Alene for many years.]
*There has been some discussion in another thread about dissatisfaction with the seat and steering wheel heaters. So far as I can tell, it is being expressed by those attempting to test them in balmy temperatures. In my 2012 LEAF they work very well and are quite pleasant to use in cold (20s-40s) to very cold (<20s) temperatures; I don't mind the cycling of the thermostats at all. Perhaps Nissan has changed the design or specs on the 2013s but I have my doubts about that.