What if the Blink gets stuck charging? I know the immediate follow-on question is, "Can the Blink really get stuck?"
Last night, the Blink was in a typical "behaving badly" mode, where you couldn't connect to it via the network. It was charging the car at the time. I have read somewhere, and I couldn't find the thread, that if you tried to go to "settings", it would hang at that point. I saw this for myself. My recollection about the discussion was, that it would recover after the charging was done. But I was kinda concerned that it might not come out of charge mode. When I checked subsequently, the screen had turned off. Tapping it brought it back on, but it was still "processing". Well, I figured, since the screen saver was working, and that's like the most difficult bit of programming Blink has done to date,
that probably the UI was stuck but not the rest of the functions in the box. So, I let it run.
I got a "charge complete" message from the car at 4 AM. When I checked on the Blink, it was still in the same state as before. Not responding to the network, screen saver operation, sitting at "processing", and, as a bonus feature, it was pretending to charge (now showing 8-1/2 hours of L2 so far
). I know there is a script with a good imagination in there, although I didn't expect the screen on the box to be dumb as the one it sends the browser. I unplugged the car and plugged it back in. It tried to charge for about 2 minutes and terminated when it found it was already charged. So, when the car told it to quit, it did. Clearly in this case, the "important part" of the charging algorithm was still operational. I suspect that the actual implementation of the J-1772 parts are done on a board that doesn't really care what the rest of the box does.
But my question is, if the AC supply were not cut off for some reason, can the car stop charging anyway? It takes some serious hardware to interrupt 3-4 kW of power supply (hence the loud "thunk" inside the box). So I'm not sure if the car could "refuse" it.
Happily the evidence is in favor of the EVSE not doing this, but that isn't the question. And it is a serious safety concern, at least from the battery's standpoint.