The Model S limits the regen in at least two situations:
In most situations, because there are not any large electrical loads other than the need for motive power, setting the regen limit to the battery charge limit is correct.
Heating a cold battery and the cabin is at least one major exception to that. When the battery and cabin are cold soaked to below 30˚ F. (-1˚ C.), I have seen heating powers on the order of 10 kW and charge limits of about 5 kW. This should set a regen limit of 15 kW, 5 kW for charging and 10 kW for heat. However, what I have seen is the display showing a charge limit of 5 kW and a battery use of 5 kW, meaning the regen was limited to 5 kW, and to get 10 kW for heat, the car was using another 5 kW from the battery! That is 10 kW of wasted regen!!!
I had seen this same behavior last winter, but had forgotten about it until the cool weather started this Fall. I notice this a lot because the first 2 miles from my house goes down about 700 feet, but I am sure others see this during decelerations.
Has anyone else noticed this?
- The battery is very full, like after a range charge. With a full battery, I never see the regen getting close to the orange limit line.
- The battery is cold. With a cool battery (no significant heat being added), the car will regen almost to the orange limit line.
In most situations, because there are not any large electrical loads other than the need for motive power, setting the regen limit to the battery charge limit is correct.
Heating a cold battery and the cabin is at least one major exception to that. When the battery and cabin are cold soaked to below 30˚ F. (-1˚ C.), I have seen heating powers on the order of 10 kW and charge limits of about 5 kW. This should set a regen limit of 15 kW, 5 kW for charging and 10 kW for heat. However, what I have seen is the display showing a charge limit of 5 kW and a battery use of 5 kW, meaning the regen was limited to 5 kW, and to get 10 kW for heat, the car was using another 5 kW from the battery! That is 10 kW of wasted regen!!!
I had seen this same behavior last winter, but had forgotten about it until the cool weather started this Fall. I notice this a lot because the first 2 miles from my house goes down about 700 feet, but I am sure others see this during decelerations.
Has anyone else noticed this?