Tesla charging below 0 degrees Fahrenheit.

[CyberGus]

My first Tesla experience was a Turo rental, which I drove a long distance to an appointment. The nav calculated that I would not have enough range to get back home, so I planned to visit a nearby Supercharger afterwards.

Unfortunately, a cold front rolled in during my appointment, and my remaining range dropped in half! I was now several miles short of reaching the Supercharger, and of course the mobile charger was not included with the car.

I figured I could make it by driving carefully lol, but the reported range dropped to zero right on schedule. Fortunately there's a safety margin for jerks like me, so I made it, but it was a lesson learned.

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[HaulingAss]

Another interesting fact was the rear wheel drive Model 3 only has so much preheating power due to having only one battery. So at a certain temp the battery cannot preheat.

Incorrect. The Model 3 RWD is rated down to the same temperatures as the AWD models:

Not below -30 C (-22 F) for more than 24 hours. It doesn't matter if you have the LFP battery or the Li-Ion battery, the battery is always capable of pre-heating as needed.

 

[Jager]

Lithium chemistry batteries will not charge at or below 0C/32F. A vehicle BMS will constrain charge rates as those temps are approached. So, yeah, EV's benefit from a little more planning when it gets cold.

Tesla's have negligible pack cooling from airflow while driving. But the battery pack has significant thermal mass and pack temps will often significantly lag ambient temps. And because latter-year Tesla's use not-terribly-efficient waste heat from their stators as a heat source, and because of that large thermal mass of the pack... it will take a while to heat a cold-soaked pack.

Pack heating and pack cooling thresholds have changed a bit over time with different software releases. But generally you'll see pack heating triggered (indicated by the orange "bacon strips") as pack temps decline into the 30's(F). That pack heating ceases between about 6C/43F and 11C/53F.

A recent example from a few days ago: Overnight ambient temps were down to about -11C/12F (my car is parked outside). My cold-soaked pack the next morning measured -1.6C/29F. I turned on Climate - which triggers pack heating if the pack is below the threshold. The car displayed both the blue snowflake (reduced battery capacity) and orange "bacon strips" (battery heating).

The orange "bacon strips" disappeared, and pack heating stopped, after 25-27 minutes, at which point the pack temp was 11.6C/53F.

Desired pack temps for DC Fast Charging are much higher. Preconditioning while navigating to a Supercharger will typically raise pack temps to ~49C/120F (temps will continue to rise during a Supercharger session). DC Fast Charging will work at much lower temps, but the BMS will ramp down charge rates significantly.

A single-motor EV will be slower to heat the pack because it only has one stator.

My own cold-weather protocol boils down to:

• Adding a few percent of charge - I typically charge to 55% most of the year, but I'll bump that to around 62% during the winter - to give a little extra buffer given the lowered range that EV's get in cold weather.
• Precondition the battery pack (turn Climate on) around 30 minutes before using the car, while it is plugged in.
• Charge immediately after returning from a drive, while the pack is warm.

Easy peasy. EV's require a little more thought and planning in cold weather. But it isn't hard.

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