RE: EV's in Winter - Extremes of Range
On my regular commute, the upper figures I am achieving one battery's worth-equivalent is 80 to 85 miles, which is with the 19C-to-feet setting. I would say 65 to 75mi is more the norm, though.
I am tending to drive faster because I have to do a full charge every night anyway, due to the heating requirements, and also to stay in the outside lane to avoid the debris of the crumbling carriageways in the 'truck' lanes. I have already had one heavy windscreen strike from a lump of tarmac while being in the inside lane too much this winter. I have therefore been upping my speed. Interestingly, I have found that if you build your power demands up gradually, the range suffers relatively less than if you attempted the same speeds in summer. i.e. driving at 52ish in winter sees ~25% less range than doing so in summer. However, driving up at motorway speeds, 70ish, there is little range difference (not counting the extra cab heating demand on top).
I am going to experiment with this a little more to understand. I think it is because if you get the cells to heat up, by higher loads, then they work more efficiently and 'more summer-like', I guess.
At motorway speeds with 19C set, I am currently routinely getting 55 to 60 mi range (in fact, this is exactly as the Fluence sales brochure suggests is typical for these conditions - credit to Renault for accurate literature and an accurate range gauge).
With rain and a few 'extra' fast accels en route, traffic depending, that can drop below 50 miles range. I've little doubt I could make that drop to 40mi range if I really pushed the car hard, but efficient driving is programmed into my right foot and I always tend to hesitate less rather than drive faster so I will usually get the best of of cars at whatever average speeds I am covering.
Pre-heating saves a relatively fixed quantity of energy: From 0 and frosty, turning the heater on consumes +1 to 1.5kWh on top of any driving and heating. From 0 and not frosty, more 0.75 to 1kWh. From ~5ish is ~0.5kWh. I don't think there is any benefit in preheating much above 5C because punching the 'demist' button puts enough 'tepid' air into the cabin space within a minute that, IMHO, you don't really get enough time to get to feel cold before the car gets warm enough! All preheating really does above 5C is waste a couple of kWh of juice from the wall in the 30 mins before the set time.
If you have the battery range, you will save 10 to 20p by not using pre-heating but simply de-icing with some warm water. When it is 0 or less and frosty, the heater will run up to 3.7kW (actually more than the max charging current) and will hold that for at least 15 minutes in the preceeding half hour before the set time. So you end up actually burning more electricity than just defrosting. Of course, the benefit is that you save 1.5kWh of range of the battery, though at a cost of 2 to 2.5kWh of preheating. Of course, preheating avoids the hassle of defrosting the car and if that's worth spending an extra kWh then you should use it, and I do indeed use preheat because 10p extra doesn't register on my worries in life. I have far bigger things to get worried about!
You will note above that I have mentioned figures from 40mi range to 85mi range. There is quite some variability possible in winter. As mentioned, you might like to try driving a bit quicker if you have the range to do so because it doesn't make such a big noticeable difference than it does in summer. You might be surprised at how little difference it makes.