I'd seen in a couple Youtube videos that the electric drive cuts out once the load got to high for the motor's.
I wanted to know myself the actual limits around this and get a feel for how it presents itself, etc so took my 2020 Outlander up a fire-track (basically an rough unsealed vehicle track, lots of which go straight up the side of a hill). I found a steep one near where I was and took 2 other adults with me (so lets say ~300kg total payload inc petrol, jack, etc).
Sorry I should have taken a photo of the track to help give more of an idea too.
I captured the data using PHEV Watchdog and have charted the relevant metrics below, enjoy...
It was a short climb, I got about 30m along before reaching a steeper 3rd wash-out at the 7:43:40 mark (you can kind of make out me slowing right down over the first two, no scrapes but I was really picking my lines and taking it slow).
When I reached that steepest part I feel the power reducing even though I was increasing throttle until forward motion came to a stop (note the car is facing up a hill). I then at 7:43:54 enabled "Charge" mode to fire up the ICE for more KWs, and then pressed "SPORT" at 7:44:02 but that just took it out of "Charge" and stopped the ICE.
As you can see with the flat RPM lines that none of this did anything. I've since noticed that at low RPM you get max motor torque (140Nm front, 200Nm rear) without a lot of KW, at least within the peak 70KW electric only I've seen PHEV Watchdog report at normal driving speeds. This seems a little strange to me as I would have expected a direct relationship between torque (Nm) and power (KW), perhaps someone here has some elec motor knowledge and can explain?
An interesting thing it was doing though is it was happy to hold the car on the slope, with me only just depressing the accelerator pedal, without rolling back, but wouldn't move forward. It really felt like a software thing, perhaps even a gradient sensor reporting too steep?
One thing I didn't try which I wish I had at the time was turning off the stability control, see if I could have at least got some wheel spin on the loose dirt and rock.