HV Charge question

I haven’t experienced weak power on hills yet, despite driving with 2 bars/0 EV range more often than not. Maybe the car is forced into a temporary HV-charge mode on a hill long enough if the battery drops below some threshold.

 

My experience: There's a small mountain grade nearby where I climb 1200 ft. Not sure the distance but all the trucks slow down to a snail's pace going up. When I went up with less than half charge on my battery in HV mode, the ICE did rev pretty high but it did not lose much charge on the way up. Last week, I did the climb again but had about 80% charge. The ICE purred quietly but pulled a good number of miles from the battery (I drove up fast, keeping up with the speedsters). It felt strong and powerful. After the top, the ICE continued to purr as I went downhill and it recharged about 10 miles of EV range that was taken on the way up. It seems that the program takes into consideration how much charge is left to decide how much power to pull out of the battery. In the earlier trip, there was about 25 miles of EV range so even though there was plenty to supplement the ICE for the climb but the program didn't take it, perhaps to be conservative, not knowing how long the climb is. Another lesson as to why you shouldn't deplete your battery during road trips.