Running out of Charge and Dead Battery

[vcor]

For those that like to live on the edge, keep in mind the battery has more power when hot. If you have less than 30 miles or so of range and you stop for a few minutes, you will likely have zero range when you start up again. As you drive, the battery is kept warm, When you stop, the battery cools off fairly quickly and a cold battery has less range than a warm one. In fact, when cold, the heater, powered by the battery, is used to warm it up and get the normal range. At low SOC and cold, it doesn't have enough power available to warm the battery and recover that last bit of range.

 

[Big Dunc]

That makes sense. Only once have I been really concerned about actually running out of battery. It was a long trip and we had bikes on the roof and there was an evil head wind and it was bitterly cold. All bets were off. I had already reduced speed several times, to keep the estimated arrival SOC above 10% (that is my golden rule).
5 miles from the supercharger is was predicting I would arrive with 11% and then we hit heavy traffic. We crawled. We stopped for a while, we crawled again and then stopped. At first I was relaxed. The journey was taking longer, but going at this speed should use less power and therefore the battery stress was gone. Or was it? Crawling in the traffic, the SoC plummeted. We made it to the supercharger with 3% left. Reading this thread makes me realise how close to the limit I was.

 

[brkaus]

@Big Dunc

If you had climate control on, that probably took a good portion of the power. But also stop and go will take more because it has to overcome inertia plus I think the rolling resistance of tires is higher at very low speeds.

 

[CB198]

Honestly, I’m not sure if this would work on a car that can’t supercharge. Unless it’s got a dead 12V you might could still tow charge it if you had a tow rope.

I think the contactors might be closed if you don’t power the car off and wait for a towing vehicle to pull your car. I’d also keep a pair of radios to communicate with your tow driver because you will be running the regen in the towed Tesla. But this is the most effective way to get out of a flatbed situation. I even thought about getting a sign for emergencies that says “tow me for $50”

 

[NewbyMaybe]

Just have a tow truck take you to the top of a mountain.

 

[CB198]

Just have a tow truck take you to the top of a mountain.

As long as that mountain is in the direction of a nearby supercharger silly goose.