During the Summer, "RapidGate" was part of any trip planning. How to keep the pack temps low to ensure a reasonable fast charge speed during the trip. There are really few options since normal driving was enough to raise temperatures during the warmer Summer days so it all became a question of which charge would be the one to shoot the battery temps beyond 110º F hoping that would be the last charge of the day allowing an overnight cool down.
Now, I noticed all this during our typical Fall weather which generally sees lows in the 40's, highs in the 50's. Battery temps were in the mid to upper 50's. But as luck would have it, we got a cold snap and a high pressure system parked over the Puget Sound region which means sunny days and COLD nights. With temperatures plunging into the mid 20's, I felt this would be a good opportunity to see how far the knee moves. It would also be nice to attempt a 3 TB reading as well!
To create a level playing field, I chose only DCFCs that will charge at least 122 Amps and they are not all created equal! The starting data is easy enough but I designated the "knee" when amperage drops below the max amperage for the machine at least 2 consecutive readings (This is not rocket science. The knee is VERY obvious) . As always, the numbers fluctuate quite a bit so 124 amps is normal. Realize with a 50 KW charger, the theoretical max on a 400 volt pack is 125 amps.
From The Bottom!
Dec 5; start; Batt temps; 48.7/47.6/45.8 SOC;32.2 Max Amps; 123.901
Dec 5; knee; Batt temps; 61.7/61.3/58.3 SOC; 47.3
Dec 3; Start; Batt temps; 56.5/55.8/52.7 SOC; 25.8, Max Amps 124.015
Dec 3; Knee; Batt temps; 74.7/74.8/69.6 SOC; 49.2
Nov 30 . start; Batt temps; 56.7/56.8/55.7 SOC; 27.5 Max Amps; 124.2
Nov 30 knee; Batt temps ; 75.9/76.8/73.2 SOC; 51.6%
Nov 26; start; Batt temps; 60.1/60.1/58.6 SOC; 29.5 Max Amps; 124.145
Nov 26; knee; Batt temps; 77.9/78.6/74.7 SOC; 52.6
Nov 22; start; Batt temps; 59.8/60.1/58.5 SOC; 26.5 Max Amps; 123.433
Nov 22; knee; Batt temps; 79.9/81.2/76.8 SOC; 52.9
Dec 06; start; Batt temps; 53.0/51.0/46.7 SOC; 47.6 Max Amps; 123.748
Dec 06; knee; Batt temps; 60.5/59.0/54.3 SOC; 56.4
Dec 06; start; Batt temps; 68.9/67.3/60.3 SOC; 38.6 Max Amps; 122.948
Dec 06; knee; Batt temps; 83.7/82.8/74.3 SOC; 57.3
Dec 06; start; Batt temps; 86.8/84.8/75.6 SOC; 49.6 Max Amps; 123.765
Dec 06; knee; Batt temps; 97.2/95.8/85.4 SOC; 63.4
Now, all is not lost. You can still get a good charge! It just won't be the first one. This can be an advantage. If you are like me, the need for stops on a road trip tend to be earlier in the trip. In my case, its due to my loading up on coffee in the morning along with taking a full cup on the road with me. This almost always means my first stop is required within the first 60 minutes. For those without home charging, this can also work out especially if you have enough charge to get at least an hour down the road. (Easy with 40 kwh!)
Now we all know the battery temps rise just from normal driving. Maybe its the higher regen profile of E-Pedal that is responsible? Either way, I decided to see if this is true when its REALLY (well for this area anyway) cold! On the three 12/6 charges, I drove from Lacey to Tacoma to Centralia to Tumwater. It was Sunny and cold with OAT running 37-42º and I noticed that the battery temps rose steadily as it always does when on the freeway doing 65 mph but it seemingly hit a wall at 69-70º. This is good!
was a bit higher than I needed it to be so I drove a bit "less
Eco mode allows a moderation of pedal input designed to reduce motor response so you can drive more "smoothly." Its like mouse settings on your computer where your mouse has to move a certain number of pixels before there is any movement on the screen. Obviously for game players, this should be very small but for the rest of us, a bit of "dead zone" is what we generally prefer.
But Eco also lowers power output to climate controls as well but if looking to boost range in Winter there is also another thing to consider and that is fan speed. Below is two LEAF Spy screenshots taken a few mins apart. Each shows the "settled" power usage of heat with fan speed of 2 and a fan speed of 5. As you can see, there is quite the difference.
Some background. I left my house at 5:50 AM so wanted to "equalize" power a bit to eliminate the very high power output that happens initially. Fan speed 2 usually starts at 2500 watts but drops down quickly to 2000 dropping again to the 1750 you see within 3-4 mins. Depending on OAT, it could stay at 1750 for entire duration of trip (11.8 miles and 16-20 mins) but have seen it drop to as low as 1250 on those super mild days. For some reason it takes what I consider to be an inordinately long time for OAT temp to settle. As you can see, there is quite the difference. Based on weather station reports (not official national weather mind you) in the area, temps ranged from 39 to 41º
Fan speed 5 gets up to 3750 and about half the time, it may drop to 3250 during the trip in this temperature range. I have seen it as low as 2500 in warmer weather.