I was not able to charge at work today (apart from 2 hours on 110V), so had to do a 43 mile return trip with 38 mile indicated EV range. I knew this could be a challenge because the elevation profile of return trip looks like this:
As feared (but partially hoped for--- for the sake of science), the REX finally kicked in around Mile 40 (on the big final hill). I immediately slowed from 70-75 MPH to 65MPH. As soon as the blue bar moved to the left of the white arrow (SOC below 6.5% and falling), I set cruise control to 56MPH. I had radio off and was listening for the REX. I could not hear it. I suspect it was in warm up mode for at least 3-4 minutes (ambient temp around 70degs). The SOC kept shrinking, but slowly. Through some ups and downs (but still fundamentally pulling a big hill), I think I heard the REX get louder (but very hard to tell on open road). The SOC bar was not growing, but it wasn't shrinking either, so I sped to 60MPH (speed limit is 65MPH). When I was getting closer to the summit (and what I knew would be slowing traffic), I picked up speed to drive with flow of traffic (around 70mph). SOC went down, but not close to zero. As I slowed down from 70MPH to 35MPH or so, I could definitely hear the REX get quieter, but it was still chugging away. The last part of my trip is all downhill. Gravity and the REX recharged my buffer and the REX shut off completely for my last mile or so of surface street driving.
Two observations: First, the 55-56MPH sweet spot really does seem to help, especially while REX is in warm up mode. Although a bit annoying that I had to actively manage this scenario, at least I didn't naively hit the wall and face the 25MPH crawl of shame.
Second, as I reflect on the last five miles of my trip, I sort of wish I could have manually TURNED OFF the REX at the summit (or perhaps even a bit before the summit), knowing that I would be going downhill for the rest of the journey where I would do an L2 charge. Although I didn't burn much gas today, I burned most of it to charge the SOC back to 6.5% right before I plugged it in for a full charge. Kind of a perverse outcome, no?
Would be cool to have not just a Mountain Mode (move SOC buffer target to say 20%), but ALSO a "Stretch Mode" (move SOC buffer target to 2.5% (or whatever). With this level of control, I could have (i) kept driving at 70MPH with the flow of traffic up a pretty steep hill AND (ii) burned less gas overall.
As feared (but partially hoped for--- for the sake of science), the REX finally kicked in around Mile 40 (on the big final hill). I immediately slowed from 70-75 MPH to 65MPH. As soon as the blue bar moved to the left of the white arrow (SOC below 6.5% and falling), I set cruise control to 56MPH. I had radio off and was listening for the REX. I could not hear it. I suspect it was in warm up mode for at least 3-4 minutes (ambient temp around 70degs). The SOC kept shrinking, but slowly. Through some ups and downs (but still fundamentally pulling a big hill), I think I heard the REX get louder (but very hard to tell on open road). The SOC bar was not growing, but it wasn't shrinking either, so I sped to 60MPH (speed limit is 65MPH). When I was getting closer to the summit (and what I knew would be slowing traffic), I picked up speed to drive with flow of traffic (around 70mph). SOC went down, but not close to zero. As I slowed down from 70MPH to 35MPH or so, I could definitely hear the REX get quieter, but it was still chugging away. The last part of my trip is all downhill. Gravity and the REX recharged my buffer and the REX shut off completely for my last mile or so of surface street driving.
Two observations: First, the 55-56MPH sweet spot really does seem to help, especially while REX is in warm up mode. Although a bit annoying that I had to actively manage this scenario, at least I didn't naively hit the wall and face the 25MPH crawl of shame.
Second, as I reflect on the last five miles of my trip, I sort of wish I could have manually TURNED OFF the REX at the summit (or perhaps even a bit before the summit), knowing that I would be going downhill for the rest of the journey where I would do an L2 charge. Although I didn't burn much gas today, I burned most of it to charge the SOC back to 6.5% right before I plugged it in for a full charge. Kind of a perverse outcome, no?
Would be cool to have not just a Mountain Mode (move SOC buffer target to say 20%), but ALSO a "Stretch Mode" (move SOC buffer target to 2.5% (or whatever). With this level of control, I could have (i) kept driving at 70MPH with the flow of traffic up a pretty steep hill AND (ii) burned less gas overall.
