I would love a straight answer on that. Maybe after a long distance on the highway? But, I have not noticed any difference in the battery charge while in Hybrid mode, even after long trips throughout the city. E-Save mode with the "Battery charge" option selected, does however charge the battery noticeably. But you're also running only on gas so....
It charges yes, but immediately uses on the next ask for power. So you won’t see the % climb at all on max regen since it uses whatever is available on hybrid as the most efficient solution. Quote above is also correct on e-save.
there’s also another thread on max regen. I’ve been seeing better efficiency without it, but still charting my daily commutes to see how it stacks up over several days
Max Regen only charges when decelerating. It’s not an “all the time” charging mechanism.
So in hybrid mode, the vehicle will maintain the state of charge at around 15%. Even though it says <1% on the dash, there’s still about 15% in the battery. The system is always discharging when needed then charging when and where it can.
To maximize gasoline fuel mileage, my observation is that the engine will only maintain the hybrid battery at this 15% reserve level (display will show this as "<1%" charge level as discussed elsewhere). It would defeat the designed emissions and mileage purpose to have a mode where you can recharge hybrid batteries to 100% from the gas engine, although technically it would be possible. To get 100% hybrid battery charge you have to plug in by design. If you run the vehicle indefinitely without ever plugging in my guess is that it would maintain the 15% battery charge level only. An interesting situation would be pulling a 3500 lb. trailer up a steep grade like Pike's peak starting at the bottom with a 15% charge level on the hybrid battery. Can the gas engine develop sufficient pulling power and charging power to maintain speed and a reasonable hybrid battery charge? More of an academic question as I doubt this is a situation realized in real world scenarios!
I would speculate that your example is completely possible because of the eTorque motor/generator. That motor is designated P1. I would say that it is part of the design to keep power going to the battery no matter what the conditions are. Now in your example, could it maintain that 15% the entire trip? I’d like to think it could but I’m not sure. Since the charge curve requires a lot less work below 15%, I’m thinking it wouldn’t be that much extra work on the engine to maintain that power level.