A cold motor will be more efficient. Cold fluids and tires will be less efficient. I'd say tires will dominate.
so, if you charge in a heated garage, you should be good to go? or will the tyres cool off as you drive?
Tires have very little thermal mass and have tons of air flowing by them plus direct contact with the cold road.
Just to clarify, it's the battery warmer that is included in Alaska and Canada. This comes on after the 3 days of heating and will warm up to the 31st day after the charging cable was first plugged in. The 3-day battery heater is on all vehicles. That's the way I interpreted the manual.
I have watched the tires on the Lexus RX450h warm/increase psi from several pounds low with the tpms light on into normal temp range, light goes off, at 65mph(I-79) with temps in the single digits. Can't recall ever hearing that a tpms light came on while driving because of really cold temps. Might be something interesting to study if we could see the tpms data and log it.
I was answering your post saying it is impossible. Now you say it is. Wrong. The battery heater (operating as needed for up to 3 days provided the car is plugged-in) is for all areas. The battery warming function (starting after the heating function is stopped) for additional 27 days (as long as plugged) is for Alaska and Canada only. We had this discussion in the past in another thread but it seems you refuse to let the facts confuse you.
is this the same car with the warning in the owners manual, not to leave it plugged in after it's done charging, or you'll drain the 12v battery?
Ever heard of an intact tire that loses pressure after a drive ? I'm curious, so I'll check mine tomorrow. Ambient should be about 28-30F with snow showers during my 45 mile drive.
well, something drops my m/kwh as soon as the weather starts dropping below 70. but i don't have a battery warmer.
I did a test once. There's a particular hill I started at 40mph at the top and put the clutch in at that point. I made sure the tires were at the same pressure for each run. When it was 85F, I got to the bottom of the hill at 51mph. When it was 25F, I got to the bottom of the hill at 28mph. Remember I started at 40mph. This was only a few days apart (swings like that are common in Colorado), and I did have to inflate the tires before the run on the 25F day to get them back to the same pressure they were on the 85F day. The roads were dry on both days. In both cases I had the same starting point about 7 miles away.
Tires. Rubber changes hardness and elasticity with temperature. Try bouncing a rubber ball after it has been in the freezer. It won't bounce as high, indicating it isn't returning as much energy after flexing.
Aerodynamics...Denser air at lower temps. More internal friction...Try pushing your car in N at 85f and then again at 25: big difference.
Wasn't that. I forgot to mention it but the air density was the same both days. I do wind energy research so we calculate air density constantly.
I've noticed the same thing going down a hill in freezing temperatures. My same drive would yield 30mph at a certain point in the winter, but in the summer it would yield 50+ and I would use my regen more and get more mpg. Factors...
