Cold weather charging stats

[JohnLCS]

I'm planning a road trip tomorrow to 80% of my range, so I want to prewarm the car before setting off to maximize range. I did a little experiment this morning to see how charging in cold weather would affect the total charge time, so I could figure out when to start charging to have the car ready for my scheduled departure time. Here's the data.

2017 Model S100D, starting with 37% SOC, plugged into a 240V/72A wall charger. Parked outside overnight in 15 degrees F (-9 C) outside temperature. Cabin temperature 33 F. When I started charging, the car drew 4kW for 20 minutes (assuming battery heating). Over the next five minutes it ramped up to the full 17kW available from my charger. At that point, the car was estimating 4:45 minutes to charge from 40% to 100%. This dropped to 3:35 after another 10 minutes (car now at 42%), at which point the charging time estimate was stable. 58kWh / 17kw = 3.4h, or roughly 3:35, so that makes sense.

So my rule of thumb to estimate charging time, at least for this temperature range and charging capacity: take required capacity, divide by maximum charging rate, and add 30 minutes.

BTW, this is my first Tesla (and first post). Only had it for a month or so, but I love it.

 

[phaduman]

congrats on your purchase and thanks for posting! You might read from previous posts that charging to 80% is fast, 80->90 slows down quite a bit and 90-100% is a crawl. Your 100D has the max range of all Teslas on the road, so you should be in a good position to charge to 80 or 90% for most of your road trips.

 

[thefortunes]

congrats on your purchase and thanks for posting! You might read from previous posts that charging to 80% is fast, 80->90 slows down quite a bit and 90-100% is a crawl. Your 100D has the max range of all Teslas on the road, so you should be in a good position to charge to 80 or 90% for most of your road trips.

The OP is talking about AC charging (HPWC or somthing similar).

The taper that you describe is inherent to higher speed DC charging (SuC or CHAdeMO).

 

[jjh1234]

The OP is talking about AC charging (HPWC or somthing similar).

The taper that you describe is inherent to higher speed DC charging (SuC or CHAdeMO).

AC charging tapers too, just later.

 

[thefortunes]

AC charging tapers too, just later.

Nowhere near the dramatic reduction in speed that high-speed DC does (which is what phaduman was mistakenly referencing).

 

[phaduman]

Good point there @thefortunes. Would be interesting to know if HPWC charge time from 90-100% is the same as AC charging. The taper feels more dramatic on the supercharging because relatively speaking, the first 10-90% was so fast!