A few days ago I posted results from running the battery way down past zero. And then I charged it over night at 12 amps with the big 240 volt charger.
It took about 12 hours to go from zero to 100%. This is much less than half of the charge time at 120 volt 12 amps, which I measured at well over 30 hours back in the heat of summer. See an older post.
But it is cooler now, and the battery fan runs much slower. I suspect that is the major difference.
One of these days I will analyze my log file (now posted in with the blog links on the right) and see if I am getting noticeably more juice into the battery at work in this cooler weather. But I can't do it right now, I am spending too much time driving my Mini E.
By the way, I am noticing some trouble getting the Mini E to start charging from the 240 volt big box when the car is set for 12 amps. Sometimes it starts and stops, and I have to pull out the plug and put it back in, sometimes twice. At first I thought that was because I had run the battery down so far in the experiment a few posts back. But now I notice it even when the battery is above 25%. Maybe it has always been like this, and I only noticed it with the small 120 volt charger that can only be used at 12 amps. It is only recently that I have started just leaving the car set for 12 amps almost all the time because it usually charges fast enough overnight to reach 100% by morning. The idea is to draw most of the power late at night when the grid load is low.