I work on electric powertrains for a living. I know what happens to a lithium-ion cell at 10°F. I know the math on cabin heating energy draw. I know that "EPA range" is a number generated at 77°F with no accessories running, which is to say, a number that describes a car that does not exist in Michigan in December.
So when I decided to drive a Tesla from Detroit to Los Angeles and back — in December — I wasn't doing it to prove EV skeptics wrong. I was doing it because it sounded like a good way to spend a few weeks off, and because I was curious whether what I know on paper holds up when you're the one sitting in the car at a Supercharger in Amarillo at midnight.
The route
Detroit → Chicago → Kansas City → Oklahoma City → Amarillo → Albuquerque → Flagstaff → LA. Then back the same way, roughly, with a detour through Las Vegas because why not. About 4,300 miles round trip.
I drove a Model Y Long Range. Mine, not rented. I'm not going to pretend I didn't spend an embarrassing amount of time in Tesla's trip planner before I left.
What actually happened to range
Michigan to Chicago on a 12°F morning: the car showed ~220 miles of projected range on a full charge, versus 330-ish in summer. That's about 33% reduction — which is roughly what the chemistry predicts. The battery management system does its job: it preconditioning the pack before Supercharger stops if you've set a navigation destination, and it does this well.
The bigger drain isn't actually the battery losing capacity in the cold. It's the heat pump pulling continuous power to keep the cabin livable. On particularly cold legs — Kansas in December cold, not California cold — I was burning somewhere around 1.5–2 kWh extra per hour just on HVAC. Seat heaters instead of cabin heat helps. Steering wheel heater. Anything that heats you instead of the air.
Supercharger infrastructure
Genuinely impressive on this route. I never waited more than 10 minutes at a charger. The only stress point was a 150-mile gap in eastern New Mexico where you need to arrive with margin — the planner accounts for this but it's the one leg where I kept the speed down and watched the percentage more than I'd like.
Albuquerque to Flagstaff has elevation change that works in your favor going west (regen on the descent into the Colorado Plateau) and against you going east. That leg going back I arrived with more charge than projected because the planner is conservative. Which is the right call.
What this taught me that the job doesn't
I calibrate control systems. I work on the software that decides when to draw from the battery, when to regen, how to balance state of charge against thermal constraints. I've done all of that work at a desk, with models, with dyno data.
Driving 4,300 miles in winter in a car I work on adjacent systems to — it doesn't make me better at the job exactly, but it puts the job in context. The numbers we optimize aren't abstract. They're the number on the screen in Amarillo at midnight, and whether it's big enough that you're not thinking about it.
The car handled it fine. Better than I expected on a few legs, exactly as expected on others. If you're an EV skeptic and you want to argue about this, I'm happy to, but you'll need to bring data.
LA
It was 72°F. I ate tacos and went to the beach. The car had full range again. I left after a week and it was 15°F when I got home. The circle of life.