So Mike, based on what you said, I’m assuming you use low regen for long highway trips? I had asked this question earlier in this thread and was asking if anyone had done controlled highway tests with regen on high and then low.
I’m actually surprised BEV reviews don’t go into this discussion. I haven’t even seen it discussed on the Tesla forum.
Thanks for the reply - Concerning coasting regen, it all boils down to exchanging momentum for energy or using the same momentum to coast to save battery energy. The later is more efficient, since the regen energy gained to hold the cars speed down, will take nearly two time that amount of energy to power the car back to the speed lost.
If you take two cars running at 55 mph and as we top the hill, one car uses regen brakes to maintain 55 mph and the other is allowed to coast to 65 mph, as these two cars reach the next hill, the coasting car has two advantages:
1) The coasting car will reach the next hill sooner since its traveling faster.
2) The coasting car will travel further up the hill since it has more kinetic energy stored from the higher speed.
When you consider the further distance the coasting car traveled, it would generally take almost twice the power you captured in regen to move the car to that distance.
It’s important to note, when you compare performance of an electric motor to its performance as a generator, its far from being 1 to 1 ratio, since the motor is primarily designed a motor first and a generator second.
Therefore, if you were to regen one mile at 55 mph, you would not store enough energy to travel the same mile you recuperated. While each car is different and effected by many variables such as; ratios, temperature, vehicles weight, BCM, motor size, etc., generally speaking, if you were regen down a long steep decent, most EV’s would have to regen around 3 miles to add back one mile of range.
For the most part, unless you enjoy experimenting as I do, you really don't have to be over-concerned with regen. In addition, if your live in Florida which is flat there is little to no advantage to coasting regen using the speed control. Where high coasting regen is useful in city traffic or rolling traffic on X-ways, as it allows the car to be driven somewhat like an I-3 using one pedal. I might mention the I-Pace has a very useful “Vehicle Creep” feature where the vehicle will "roll" like a conventional automatic trans or “hold” after you stop. This feature adds a whole new perspective to coasting and stopping the car with regen, be sure to give it a try.
Stay Safe - Mike