jaapv said:
In fact, 1500 kg is a rather conservative value.
I don't agree with that. I have had occasions of 'reduced propulsion power' while towing my 1500 kg caravan on the motorway, so I think my caravan is right at, if not over, the limit.
On the short run (or at local speeds), the car is absolutely great while towing and can do much more than 1500 kg, I agree. But on the long run it has an issue with maintaining battery charge in parallel hybrid mode. There are simply not enough RPMs to produce the power needed to keep going. So, the E-motors + battery must help out, nearly most of the time. Once the battery is depleted (maybe after 200 kms or so, provided you have engaged Charge mode from the beginning), the car will switch to serial mode, allowing for more RPMs and thus more output. This way the battery can be recharged a bit. You end up in a hysteresis cycle of serial - parallel - serial - parallel. Not very comfortable (to the ears) and not very fuel efficient. But more concerning is that under some driving circumstances, even in serial mode the power output with a depleted battery is not enough to maintain your speed. Don't forget, it is only 60 kW at best! The battery will be depleted even further, until management steps in. And at that moment propulsion power will be limited and you will be "crawling" up hill.
Now the thing is, the above is probably more related to frontal surface of the caravan (and drag) rather than weight. And my caravan is 'only' 2.30 m wide. Had Mitsubishi set the towing limit to 2000 kg, I think a lot of people would have tried towing 2.50 m caravans with it. And I don't think that that would be a good idea. Knowing what I know, I will never try this. At least not for other than local trips.
BTW: The PHEV was first introduced with a tow rating of 1600 kg in the Netherlands, but this was reduced to 1500 kg before they started taking orders. Must have been a reason for this.
Some more thoughts:
I believe legislation says hill start at 12% must be mastered
three times within a limited time span (15 minutes or so)
I think curb weight is not a factor perse. Outlander Diesel is not heavier than Outlander PHEV and can tow 2000 kg in the Netherlands. There have been Ford S-Maxes and Mondeos that could tow 2000 kg where others, with particular gear boxes, where limited to 800 kg.
Why would the braking system of the PHEV be less than that of a conventional Outlander? The fact that you have regen braking means less load on the conventional brakes and to the best of my knowledge, there is no single indication that the conventional brakes on a PHEV are any less than those on a conventional Outlander.