I heard something today that makes me very skeptical. A dealership claimed that charging an EV with 11 kW has higher energy efficiency than charging with 6 kW. (And they didn’t mean 3-phase vs. 1-phase!)
Even if it is somehow related to battery temperature and receptiveness, that would still be heat loss. With higher currents, resistance increases, too, no? Or is it proportional and always the same percentage?
In any case, I find it foolish to follow such advice because there are other factors involved, mainly a battery suffering more regarding longevity if charged faster, and that is a lot more expensive of a loss, eventually, also because an older battery is generally less efficient in several ways. (internal resistance, self-discharge)
Plus more load spike on the grid, external and house. But I don’t want to rant too much about the lack of reason in the world that seems to be a self-amplifying spiral of doom. Apparently house charger impatience is a thing. Three hours of charging twice a month - absolutely intolerable to some.
It will be more efficient if you have to warm up or cool down the battery to charge since the time to charge will be less, so less energy wasted for that process