A Matter of Degrees

Large flock of birds in Iowa.

It’s been exciting learning how the Tesla handles cold temperatures. I have driven several (6) long trips of about 1000 miles each with the Tesla and only on the first trip did I freak out about getting to a charging station. Yesterday (Saturday) we woke to temps in the 20’s (f) and it got colder during the day. I charged the car in the evening and when we went to leave the next morning the car had lost about 30 miles of charge.

The trip in cold temps was interesting. On a normal day the car uses energy at a rate of about 275 watt hours (WH) per mile. (I won’t explain what a watt hour is but the number values will be pertinent.) All day, in the 20 degree temps, the car was using over 400 WH per mile. Almost twice as much. We had to stop and charge more often than normal and extended the day quite a bit.

In thinking about this I could only guess as to why this happened. First, the car is heated and cooled with a heat pump, similar to the ones in homes. Just like at home, when it’s THAT cold the heat pump just doesn’t work. It has to use a resistant heater (like a hair drier) and that uses a lot of energy. Second, I was driving as the lead car and getting a lot of wind resistance, using more energy. Later in the day, I had Linda lead and that helped. Third, just like any battery, the car battery did not like the cold.

The next day (today), I monitored and recorded some statistics. The day started off with temps at the low 40’s (f). I toyed with the idea of wearing shorts. I spent the first 30 miles glued to the energy monitoring apps (full self-driving has advantages). With just a 20 degree rise in temperature the car was using about 310 WH per mile. Much closer to normal, plus the temps rose to the low 70’s later in the day. I continued to have Linda as the lead car as it did make for an improvement for the Tesla. The miles per gallon in the Jeep dropped by driving at 75 mph (the speed limit).

Take aways from this are 1. Plan on more charging stops in cold temperatures. The car doesn’t know the weather. 2. Look ahead on your route for charging stops and plan your speed. The speed limit in Nebraska is 75. If Linda was not in front, I would have had to limit my speed to 65 so as to get to the next stop. The charging stations were far apart.

All in all, not bad, just did not think about cold weather behavior.

By Linda

We saw a murmuration of black birds yesterday that was amazing to see. Today, we came upon a large number of birds and managed to get a video. It’s not great since I was driving on an interstate at the speed limit, but I had the phone in navigation mode and was able to flip it over to video quick enough to give it a try. I do not know what kind of birds they were. I would have stopped if I could.

A large number of birds flocking on the left side of the highway.

On the way through Nebraska, we saw flocks of sandhill cranes. Audubon says, “Between February and April, more than half a million sandhill cranes gather on the Platte River in central Nebraska, staging for a journey that ends as far north as eastern Siberia.” Way, way cool to see. I wish we were in a better position to have hung out in the area to observe more closely.

We are halfway through our journey to Bremerton. We should beat our initial travel plans but weather is always an issue. We can’t drive in the snow and an atmospheric river in the Pacific Northwest could cause problems. Tomorrow looks good and traffic is much better in this area, so we hope to make good time for another day.

Yesterday the temperature was 20 degrees F in the morning. This morning, it was 40 degrees F in the morning and rose to 70 as we made our way through Nebraska. It was likely around 80 degrees F the days before we left in Florida. 80 to 20 to 70 in a few days. I hope it does not plummet again.

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