1. How will the car start each morning? In a heated, enclosed garage? Enclosed unheated garage that is significantly warmer than ambient? I'm sure you know that you should preheat the interior with the car's timer, your LEAF app on your smart-ish phone, or CarWings through the internet (there's actually a text message service now that I like; just type "AC on" and hit send).
In the summer, absolutely, this is easy as pie. In the cold, i would absolutely charge to 100%. If you're pushing snow and the car is starting cold/cold (that means cold battery and cold climate control), you'll probably make it, but with quite limited reserve. Any detour might make for a cold walk home.
So, let's hit this with a worst case scenario. It's -20C/-4F in the upper P, and the snow is dropping hard. Traffic is jammed up because of cars stuck in the snow and crashes. You have to detour around some of it, adding numerous miles. The car was fully charged sitting outside, but you forgot to turn on the heater. Don't worry about that battery freezing, though, 'cuz that 300watt battery heater is warming it up to -10C/14F. At least you don't have a Blink EVSE, so there's a good chance that as long as power was available, the car was fully charged.
1) .2 miles 25MPH subdivision
2) 4 miles 45-55MPH rural (2 stop lights)
3) 3 miles 25-35MPH city (2 stop lights)
All combined to 14.4 miles at 4.0 miles/kWh for my example, which might be too optimistic in significant snow.
4) 13 miles 55MPH highway (5 stop lights)
Ok, let's guess 3.5 m/kWh while pushing snow for 26 miles
5) 6 mile 40MPH city (6 stop lights)
6) .3 miles 15MPH parking lot (Both ways totals 53 miles)
7) 3 miles of 40MPH driving for lunch-time errands (56 miles)
8) 4 miles to that (60 miles)
I'll give you 4.0m/kWh for this 26.6 miles
To be honest, temperature is relatively easy to factor (just turn the heater off, viola, end of wondering how much, plus battery capacity seems to be somewhat linear with temp). But, snow? If you snow ski, you know how much that can vary with snow conditions.
40 miles @ 4m/kWh
26 miles @ 3.5m/kWh
66 miles total round trip at 3.7m/kWh equals 17.83 kWh burned with ZERO heater factored. So, how much battery is there? 70F minus 14F (the warmest the battery was warmed to while plugged in) is a 56 degree delta, divided by 4F, equals a minimum 14% reduction in battery capacity below 21kWh, or 18kWh.
Did you make it? That's not factoring in the heater, or the detour. Might want to skip those side trips! I wouldn't take my family out on a trip like this (with no reserve, no contingency plans, and really cold, bad weather), but I'd probably do it myself.
Edit: At 20F in southeast MI, assuming the battery is near that temp, you'll have a bit more battery capacity, like maybe 2% over 14F.
Last edited by TonyWilliams
on Sat Mar 03, 2012 11:06 pm, edited 1 time in total.
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