Ok, getting some data points on my Blink unit.
First, it didn't charge overnight Sun night/Mon morning. No text from the car or the Blink, just 1/2 a battery charge in the morning. That night it wouldn't charge when I plugged it in and I switched to the 120V unit. No indication of any problem, just no juice. I realized while paging through the menus that I had swapped out WiFi routers on Saturday. When I reconnected it to the WiFis, it downloaded new software, rebooted and after it was up and running, I plugged it back into the car and it started charging.
Second, at totally random times I get texts from the car saying "Charging was interrupted". I can go straight to the car and see it is still plugged in and charging, but it will say only a minute or two of charging (even if it was plugged in for hours). No resolution to this, but it has not happened since Monday.
Now, I just installed and air conditioner in my garage and it plugs into the 220V line (separate circuit from the Blink). I shut the A/C off a minute ago and the car started beeping 3 quick beeps followed by a pause a few times, then stopped. I think maybe the Blink is sensitive to load-dumps on the 220V line and needs some capacitance and maybe protection diodes on the front-end. Anyway, the car still shows charging for almost three hours, so it did not cause a reboot. Just documenting what happened...