EV Street - Electric Vehicles for Dinosaurs

Electric Vehicles have come of age. But, it's going to take a revolution to make it happen.

Saturday, January 26, 2013

Living with the Nissan Leaf part IV

Well, it's been over a month since my last post, and it's still been interesting working with this car. We've had a very cold spell here for the last two and half weeks, lows in the low teens and highs in the 20's (Fahrenheit). The car is parked in the garage overnight. But the garage is not insulated so the temperature in the garage in the early morning was only about 20 degrees above the outdoor (so low 40's). It's fantastic to not even have to think about "warming up the car."
But cold weather sure cuts into your range, on multiple levels:
1. Running the heater at these temperatures to maintain a comfortable cabin temperature impacts the range by a little less than 20%. In terms of heating power, the system is quite sufficient so the choice is yours to trade comfort for range.
The power gauge shows the heating system will peak at about 5.5KW before the system warms up. If you make sure your venting is set to recirculate, it will drop back to about 3KW when warmed up. But if the vent is open, it will be trying to heat the colder outside air and will stay a little over 4KW. You might think that is excessive to heat such a small space you're correct. A 1.2KW hair dryer would probably warm the space up quickly... if it weren't contained with 40% single pain glass and a cold 50MPH air stream running over the exterior.
In this regard, Nissan was clever to equip the car with a heated front seats, a heated steering wheel and, heated rear seats! The power draw from these systems is far less that the cabin climate control and the sensation of warmth is nearly complete. Choosing to use these systems has an almost negligible impact on the range.
2. The battery's performance lessens as the pack gets colder (less range). A warmer garage would help in the mornings but if the car sits too long outside it will cool further.
3. No way to measure this, but colder air is denser. Denser air requires more energy when the vehicle is moving at higher speeds like on the freeway. Also, cold weather like this keeps snow, ice and gravel on the road which increases rolling friction. Also, it lowers your tire pressures, also increasing rolling friction.
All these factors are visible in this cold situation and manifest themselves by ultimately reducing your range. Suffice it say that, the practical 70 mile range most people hold up for this car is still optimistic when the temps get below the 40's for an extended time. You must sacrifice cabin comfort and be more vigil on your energy usage to get that 70 miles, under my circumstances at least. After all this complaining I will still say that the car is remarkably well developed for most situations and that if you doing the recommended 80% charge, you can counter act this shortcoming by doing 100% charges during these cold times.


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