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What if the Blink gets stuck charging?

Posted: Fri Jun 10, 2011 12:07 pm
by gbarry42
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, :lol: 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.

Re: What if the Blink gets stuck charging?

Posted: Fri Jun 10, 2011 12:39 pm
by LEAFer
gbarry42 wrote: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.
Yes, the car can indeed "refuse" it. And it won't "expose" the battery to it.

The Blink might keep the contactor closed, meaning the J-plug is still energized, which is *NOT* a good thing and could cause arcing when you physically unplug it. The J-plug (after removing it from the car) may continue to be energized, which again is not a good thing, but it's relatively safe, unless you are in very wet environment (think puddle) or mess with the plug with "tiny instruments".

If you are aware of the fact that the Blink did not de-energize the plug, you might want to unplug the Blink (or trip the circuit breaker in the panel/sub-panel) before unplugging from the car or plugging it back in.

Re: What if the Blink gets stuck charging?

Posted: Fri Jun 10, 2011 2:11 pm
by DeaneG
My Blink has frozen a couple of times this week after charging. Once with a permablack screen, then a day or so later stuck on "Processing...". Unplugged it to reboot both times.

Re: What if the Blink gets stuck charging?

Posted: Fri Jun 10, 2011 2:39 pm
by Herm
Piece of c***, this is what happens when you needlessly overcomplicate an extension cord.

Re: What if the Blink gets stuck charging?

Posted: Fri Jun 10, 2011 3:09 pm
by smkettner
EVSE only offers power. Leaf will not charge beyond 80% or 100% as you have designated.
I think I am OK at this point to not be part of the EV Project.

Re: What if the Blink gets stuck charging?

Posted: Fri Jun 10, 2011 3:38 pm
by DeaneG
Herm wrote:Piece of c***, this is what happens when you needlessly overcomplicate an extension cord.
I like to think of it as overspecified and underdeveloped.

OTOH, I was going to buy a Leviton EVR-160, where is that?

Re: What if the Blink gets stuck charging?

Posted: Fri Jun 10, 2011 5:39 pm
by davewill
LEAFer wrote: If you are aware of the fact that the Blink did not de-energize the plug, you might want to unplug the Blink (or trip the circuit breaker in the panel/sub-panel) before unplugging from the car or plugging it back in.
Definitely the breaker. All the arcing concerns apply to the wall plug in spades. I do know from the mod thread that the EVSE function is handled by a satellite board and processor, so I doubt the turn off of the contactors would fail, even if the screen is dead...but better safe than sorry.

BTW gbarry, if you hear the relays clunk when you kill the breaker, you'll know you were right.

Re: What if the Blink gets stuck charging?

Posted: Fri Jun 10, 2011 6:08 pm
by gbarry42
Well, if I can guide this thing back on topic...in my case it was pretty apparent that my charging had stopped. I suppose I could have looked at the blue lights in the car if I had thought about it. So there's never been an issue regarding stopping the thing while it is live. So all that speculation is...speculation.

What I want to know is, in a theoretical "stuck EVSE" scenario, how can the car disconnect itself? Something like 600 volt F.E.T.s, or maybe all those little clunkity-clunk relays under the floor. I guess I wanna hear from Gary or Phil (or Tony, who's had his fingers in everything :)) on this.

Re: What if the Blink gets stuck charging?

Posted: Fri Jun 10, 2011 9:05 pm
by GroundLoop
It is good and NORMAL for the Car to disconnect itself.

This happens at every end-of-charge.
The car is, after all, in charge of charging. The EVSE is just an extension cord with a fancy plug.