Some time ago I contacted my local service center in Brussels for a different issue. I asked about charging and why a single charger in Europe takes 16A on a single phase. He mentioned that there is an update of the single charger in the works that would allow European single charger to take more current (32A?), but was not sure about any details.
Since then I can not find any information on this. Does anyone know anything? Or have I misunderstood, since I am not very bright with these things?
I am fairly sure that an upgrade is not only in the works but now rolling out (at least in UK cars, and it would be strange if not applied to other european cars).
Considering only european models:
Original single charger cars can accept only 16A per phase (ie. 16A on up to 3 inputs). The blue adapter on the UMC connects the three inputs together, so the car can use 32A total (split between the multiple inputs). Standard chargepoints don't do that (supplying up to 32A but only on one pin on the connector), so these cars can only draw 16A from such chargepoints.
Tesla seem to have considered this "OK" for most of Europe where three-phase is quite common and the UMC was supplied bundled with the car.
When Model S deliveries started in the UK (June '14) there was a problem: three-phase is very rare in homes here, and we have a government subsidy for installing standard chargepoints - hence most people would already have a 32A single phase type2 chargepoint (the subsidy at that time was enough to make them free or very low cost). Tesla initially started working with one of the chargepoint installers on the government subsidy scheme to hack their chargepoints to have the same wiring as the UMC, but then a few weeks later they reversed that plan and the modified chargepoints were removed from those people who had them and replaced with standard ones. I have since heard that plugging a Renault Zoe into a chargepoint with that wiring causes damage (both to the chargepoint and the Zoe), which may be the explanation.
So Tesla changed plan again, and all UK cars were delivered with two chargers fitted: people who had only paid for 1 charger then got a software update that disabled the second charger except when working in single-phase mode. These owners were able to pay the difference in price and have full use of their second charger.
Cars delivered to the UK recently appear not to have the 2nd charger, yet can still charge on 32A single phase with standard wiring. It appears that there has been a change to the hardware in the car to allow this (might not a change to the charger itself, the extra contactor could be in one of the various junction boxes).