Rolling into Barstow on Electro-Fumes

[canyonwalker]

Saturday afternoon we began our 500+ mile drive back to the Bay Area after eating lunch and charging up the new car's battery. Our plan for the remainder of the day was to drive to Bakersfield, CA, 290 miles away. We'd stay overnight in Bakersfield. But as 290 miles was well beyond the car's maximum rated range of about 250 miles we planned a stop in Barstow, CA, 161 miles away.

Planning stops is a thing you've really got to do with an EV that's so much more critical than when driving a gas or diesel engine car. The reason is, with 100+ years of building out infrastructure, there are gas stations practically everywhere. EV charging stations are not everywhere. And while slow charging stations are somewhat common, the kind that can charge an EV rapidly are few and far between outside large cities.

We didn't expect that getting to Barstow would be a problem. But we almost didn't make it! Fifteen miles outside of town the car flashed up an alert on the dashboard: only 10% charge remaining. And the estimated range remaining was only 15 miles. We'd roll into town on fumes... electro-fumes! 😱

Where did all the range go? We had about 220 miles of range when we started this 161 mile leg of the trip. Well, the car was suffering poorer fuel economy than normally estimated. A few things:

1. It was hot. Temperatures ranged from 100° up to 110° (about 43° C) all through our drive. In hot weather the battery is less efficient and the cooling systems have to work harder.


2. We were driving fast. It was all highways at fairly constant speeds, but we were driving 80-85mph much of the way. (Note: we were driving with the flow of traffic. This is common on I-15 between Vegas and LA.) The motor has to work harder to overcome wind resistance at higher speeds, and resistance increases as a function of the square of the speed.


3. There were a few mountain climbs from elev. 1,000' to 4,000' on the route. While the EV regenerates power coasting downhill, it doesn't recover as much as the extra energy expended climbing uphill.

After the warning flashed up and we had our initial "Oh, shit!" reaction, I decided the best way to stretch the remaining charge was to drive slower. Dropping from 80-85 down to about 65 mph added back a few miles of range. Still, it was close. When we rolled in to the charging station in Barstow we had an estimated 5 miles left.

Comments

[some_other_dave]

If I remember correctly, the dominant factor in aero drag actually goes up with the cube of speed! (Though, since it's aerodynamics, the actual figures are more complicated.)