Nfuzzy said:
dgpcolorado is right that this is not something I have to worry about often here. We will only get a handful of days per winter that I may even have to think twice about blasting heat to conserve range.
My roundtrip commute is only 30 miles but I can't charge at work and the car will be sitting outside for the 9 hours or so workday so I wasn't sure if I'd see much range drop just having it parked out in the cold all day.
Short answer: not much range drop with the car sitting for just nine hours at typical Colorado Springs winter daytime temperatures. Thirty miles round trip is easy in winter in Colorado. You can even preheat the car remotely (assuming an SV/SL model with Carwings) before you head home and get into a warm car!
The battery has a lot of thermal mass and cools (and heats) slowly by conduction. Charging heats the battery. Driving heats the battery, especially at high kW discharge rates (freeway speeds or climbing steep hills). So, by the time you get to work your battery will likely be warmed up somewhat from the ambient temperature. Then it will cool off slowly from there on cold days.
If you keep the car in an attached garage at home it will likely stay fairly warm overnight (at or above freezing, although it depends on the garage). If you park outside, then the occasional below zero night will get the battery pretty cold unless you are charging. The battery doesn't charge well when it is around 0ºF or below (the battery heater comes on at a battery temperature of -4ºF and turns off at 14ºF, last I heard).
For the folks in other states, who routinely deal with below zero for days at a time, it can be a problem. In sunny Colorado? Not so much. The battery just isn't likely to get all that cold if you are charging and driving the car regularly.
That said, a cold battery will have reduced capacity compared to a warm one. And cold air is more dense than warm air, meaning greater drag. And cold tires and gear lube mean greater rolling resistance. Add it all up and the range is reduced in cold weather versus warm weather. However, on the plus side of the ledger you are at fairly high altitude in CS
* and that means significantly reduced aerodynamic drag, compared to low elevation parts of the country. That's why we get better range (and gas mileage) here in Colorado than those in most other parts of the country, at a given temperature. (When not driving up and down mountains, that is...)
* The air is about 20% less dense in CS versus sea level, at the same temperature.