When towing heavy trailers (that might weigh twice what the truck weighs), controlling the trailer brakes properly in relation to the truck braking is critical for keeping the combination stable. For best stability, you don't want the trailer pushing the truck from behind. If you are braking hard, and the trailer is pushing hard from behind, and hit some wet or sandy pavement, you have the perfect conditions to push the truck off the road or provoke a jack-knife.
So for the sake of stability, you want the trailer brakes to do most of the stopping of the trailer. That means the EV regenerative braking cannot harvest too much energy from the trailer during braking. Hopefully Tesla figures this out and they include an integrated trailer brake controller that does the right thing in conjunction with the truck brakes and regen.
This need to use the trailer brakes more heavily is an important consideration when estimating range when pulling a heavy trailer up and down hills. I have seen some estimates that presume some high percentage of regeneration of the trailer weight on the downhill segments. But to the extent trailer braking is necessary, that energy will be lost.
So for the sake of stability, you want the trailer brakes to do most of the stopping of the trailer. That means the EV regenerative braking cannot harvest too much energy from the trailer during braking. Hopefully Tesla figures this out and they include an integrated trailer brake controller that does the right thing in conjunction with the truck brakes and regen.
This need to use the trailer brakes more heavily is an important consideration when estimating range when pulling a heavy trailer up and down hills. I have seen some estimates that presume some high percentage of regeneration of the trailer weight on the downhill segments. But to the extent trailer braking is necessary, that energy will be lost.