I took delivery of my i3 in February. Have been commuting 100 km more or less daily since then. In cold weather (living in Sweden) I've been charging outside my workplace since heating the car have significant negative impact on range. Two weeks ago I noticed that the car wasn't charging although plugged in... Called my BMW dealer, who decided to haul my car to the BMW service center. They very soon came to the conclusion that my EVSE unit had failed due to water damage. They replaced it with a new one which was "improved".
The original EVSE unit was IP44 rated, don't know what the improvement did in IP rating. However I'm planning to by a separate EVSE with IP55 and 16A capability, leaving the original inside my garage as a "wallbox".
So my general advice is that you should be careful with how to use the original EVSE in outdoor use or have it replaced as soon as possible as a warranty claim...
I'd be very interested to know where you source an IP55 16A replacement (assuming you don't build it yourself),