Our LEAF has crossed the 5,000 Km mark today. The car is doing great after 2.5 months since delivery. At this rate, we’ll probably hit 24,000 Km in a year, 20% more than we first predicted. No problems with the car so far, and I haven’t got stranded yet. 🙂 The range has been more than enough for the kind of drive we do in the city, and we’ve been getting plenty of chances to recharge both at home and at work.
Cost of ownership has been really low and impressive. We spent about $30 in electricity with the LEAF in October, and $35 more in November, and drove almost 2,000 Km in each month. Charging at IBM helps, but the trickle-charging at mid-peak hours is just enough to cover the 34 Km round trip to work so most of the charging still happens at home, which is much faster, more efficient and can be done at off-peak hours, when all the coal fire burning power plants are safe at sleep (Ontario still has 18% of its electricity coming from coal but mostly to respond to peak demand).
These days, I’ve been getting a lot of questions about the winter, though we haven’t got much of a winter yet — barely crossed the freezing mark, but it’s been enough to give us a feeling of things to come. I’ll try to summarize it below.
How does it drive in the snow?
Not much different than any other car. Winter tires have been working as expected, with ABS and traction control doing their job, so nothing new really.
How does it drive below freezing?
Response and acceleration are about the same. The *power* (KW) is there when you need it. The difference is in how much *energy* (KWh) you’re able to draw from the batteries at lower temperatures. It basically means the lower the temperature, the lower the range.
How far can you go in the winter?
The estimates provided by Tony Williams’ Range Chart at the My Nissan LEAF Forum have been fairly precise so far. The chart predicts a 1% drop in range for each 1C drop in temperature below 20C. This is very in line with what I have observed since the temperature started to fall.
As an example, I’ve monitored a 76 Km round trip we did last week, mostly on highways. We started with an 80% charge, with the guess-o-meter telling us we had 138 Km of range, which basically meant: if we continued to drive around *our neighborhood*, at 40-60 Km/h, we could drive 138 Km. Not very helpful of course. The Range Chart told me this instead: 10 bars @ 100 Km/h = 116 Km. Temperature was hovering around 5C, so 116 Km minus 15% = 98 Km range. This estimate did not include the use of climate control, which I knew we were going to need in order to avoid condensation. So 22 Km of extra room sounded good enough, so off we went. At the end of the trip, we arrived at home with one bar left, and it had just started flashing. That meant 16 Km of range according to the Range Chart (19 Km – 15%). So in summary, we drove 76 Km out of an estimated 82 Km range (98 total – 16 left), which was a very good approximation considering we used climate control during most of the trip.
Condensation forces you to use Climate Control
With heated seats and heated steering wheel, I haven’t felt any need to heat up the cabin so far, even when it’s 0C outside. The energy to heat up the seats and the steering wheel is fairly low, about 40W each, and have virtually no impact in your range. However, once you have passengers in the car, condensation starts to build very quickly and things get complicated. The A/C alone is not strong enough to keep the air inside dry, so you are forced to bring fresh air from the outside, and because this air is very cold, you have to use the climate control to warm it up. That’s takes a lot of energy compared to the heated seats: 4.5 KW initially, and then 1.5 KW once the target temperature is reached (minimum is 18C).
Expect 15% drop in range from Climate Control
Even at the minimal setting, Climate control draws a steady 1.5 KW from the main batteries. It’s a bit hard to estimate how much that will translate into range, but assuming an average 10 KW draw from the motor, that would mean an extra 15% being used. That’s the number I’m using right now to plan my trips, as a worst case scenario, but I still need more hard data to confirm it.
What’s going to happen when the temperature goes down to -25C?
No much data on that yet, but I suspect the decrease in range will not be linear. According to Nissan, the battery heaters will kick in at -20C and heat up the batteries to -10C. They will then shut off until the battery temperature falls again and hits -20C. The heaters do not take a lot of power — only 300W, and they work based on the internal temperature of the battery, which is typically higher than the outside temperature. You also have the thermal blankets, and the car itself, to help maintain the internal temperature. You can also help by starting the charger in the morning before you leave. Charging causes the batteries to warm up and that will boost your range a bit.
So overall, what do you think the impact of a harsh winter will be?
I “guesstimate” a worst case scenario of 40% decrease in range for the coldest days of the year. That will still put us within a 100 Km range on a full charge, which is still well within what we usually drive. No long trips to Ogdensburg for sure, but not a significant impact to what we currently do.
I foresee some changes in habit though:
– We normally charge to 80% at night. That helps prolong the lifetime of the battery and also saves energy. However, during the coldest weeks of the winter, we will probably have to push the charger to 100% overnight.
– We will probably need a boost during the day. In between arriving from work and doing errands in the evening, we will probably need to plug in during supper (yes, on-peak hours…) in order to get the extra range if we really need to or just to be on the safe side.
– We’ll have to get used to keeping the cabin cool rather than running a furnace inside the car. We’ve been used to hot cabins all these years driving gas-powered cars, to a point of discomfort sometimes. We’ll need to change that habit in order to use energy more efficiently.
So there you have it. How have all these changes affected our daily drive so far? Not very much, really. I just have to plan a bit more, and I confess I’ve been fairly conservative and ended up with lots of left-over range at the end of day. At least, that’s a good way not to get stranded! 🙂