Still learning about my new 2017 LT.
I'm nearing the end of an inaugural ~2,000 mile road trip, basically Mexico to Canada by way of the Grand Canyon and Utah national parks, where I did not expect to find--and have not actually found--any charging facilities.
So, when I left, and every time I start it up again, I switch to Hold mode. My rationale is that, rather than burn through the EV range in the first 50 miles of a very long trip, I view the battery as an emergency can of gas, in case I run out of gas out in the boonies.
1. When in Hold, with the battery full, what happens to excess energy generated by braking and coasting? Is there an extra buffer in the battery that can only be charged by the ICE, rather than when plugged into the wall, so that the car can still behave as a hybrid even with the battery full while on Hold mode?
2. I'm about 1800 miles into the trip, charged the battery to full before I left and have not charged it on the trip, and have used Hold religiously with every start. Nevertheless, the battery level is now only about half full. So, it looks as if some of the battery energy is nevertheless being consumed in Hold mode? My sense is that it is using it most for hill climbing. The level will rise a little after a series of long descents from mountain passes.