There is no single "positive plate" in a module,; although of course the most-positive cell has positive side, it is not isolated any differently from the other cells. Each of the heat transfer fins which runs between a pair of cells and turns to contact the cooling plate is exposed to a different potential - each of them is positive compared to one neighboring fin and negative compared to the neighbor on the other side, if they are not completely isolated from the cells that they are cooling. If the fins where conductively connected to the cell terminals, any conductive plate clamped to them would be a short across every second cell of the module, and across the entire module. If the plates were conductively mounted to the frame, the entire pack voltage would be shorted through the frame.I find it odd that somehow the positive plate wouldn't be isolated from the battery case.
Mmmm, I hope so.High voltage problems are solved (I think)
Hmm, that's not really equivalent.This is 1000V but extremely low amperage. Like if you walked through the carpet in your socks and got in your car, you are not likely to damage your electronics.
Yes, and that would be the key to only testing the thing you wanted to test. However, you were already getting erratic behavior in your electronics. The unknown unknowns. So you already had some kind of path between your HV and your electronics that you didn't know where it was connected.This is also done with the 12V system disconnected so it is just testing the high voltage to the chassis.
Yes, that's fine. That's like a bridge being rated for 100 tons and then driving 100 tons across it. It better survive, and if it doesn't, it'll probably be obvious where, and you need to rebuild the part that failed. That's how the megger is supposed to be used. It tests the insulating ability of the thing you're testing, below or at its maximum rating. So you did that, and you found a weakpoint in the insulation, then you fixed it, that's good so far.And all my high voltage wires are rated to over 1000V.
Yes and no. Maybe. You know that voltage was getting to places it shouldn't have been before already, and interfering with your electronics. That's why you're troubleshooting. So, if it was already getting through there, then you give it 1000v, that's definitely enough to punch through that same area, harder. Maybe it arced and then the arcing created oxidized buildup or fried something, which then insulated it. This can happen almost instantly and imperceptibly. That's fairly normal, which leads to inconsistent behavior in the future.If I were blasting new holes through insulation the meter and data would definitely confirm that.
Hmm. How are you defining a "loss of isolation"?What I learned from John, is it is not so much a "leak" as a loss of isolation. This loss of isolation was due to the battery module cooling elements.