tps said:
lincomatic said:
Another data point showing that the Leaf violates the J1172 spec... even though my EVSE is telling the car not to draw more than 16A, it was pulling >18A the other day when my line voltage was running low again. I forgot to measure the exact voltage.
1. How do you know your EVSE is offering 16A? Did you measure the duty cycle of the pilot signal? Without knowing the duty cycle of the pilot, it's hard to know whether the LEAF is at fault or the EVSE is not operating as intended.
2. How did you measure the current? Can you give a closer value than >18A? How did you measure the voltage and what was it?
All of these findings could be quite interesting, but without more information, I'm not sure what to make of it... I centainly wouldn't jump to the conclusion that the LEAF is violating J1772, yet.
1. I have a DIY EVSE. I am sure about how much current the EVSE is offering, because I measured the duty cycle with an oscilloscope. I have another thread about this issue.. the car was pulling >12A with L1 charging. I think it's a bug in the car. It controls wattage instead of current. So say the EVSE offers 12A for L1. It assumes 12A*120V is the wattage it's allowed to draw, and draws that wattage. It seems to track that, because if I set it to 6A and it's getting 120V input, it doesn't draw >6A. What they forgot is when you have a brownout, to get the same wattage, the current goes up.
2. I measure current with an AC current clamp meter. Granted, it's a cheap one from Harbor Freight, but I've tested several times when the voltage was around 240V, and the current was floating around <= 16A.
That's why I'm fairly confident about the >18A reading. As for voltage, I measure with a DMM for L2 and a Killawatt for L1 (for L1, I use the Killawatt as well).
I've been able to do sporadic testing because the line voltage at my house has been very erratic on hot afternoons, usually floating all over the place from 115-120, when my neighbors start turning on their AC's. Lately, it's been getting worse. The other day, it went down to 104V! I know it's due to my neighbors' usage and not my own, because during these episodes, my AC is off, and I'm using almost no power in my house.
What happened the day that I saw it drawing >18A was that the Killawatt was showing voltage < 115V .. unfortunately, I can't remember exactly what voltage, so I ran outside and hooked up the current clamp to see if the car would draw >16A, and it did. I should have measured the voltage at the EVSE but I didn't, because the last time I tried to measure both voltage and current simultaneously, they were both fluctuating in real-time. I have to switch the meter between voltage and current, so it's impossible for me to get the simutaneous readings. I don't have a watt meter that works w/ 240V.
For L1 charging, I was able to use the Killawatt to measure the wattage. I have tested with both my DIY EVSE set to L1/12A and the Nissan EVSE, which is set to 12A. With both devices, I have had instances Killawatt indicated it drawing more than 1440W (12*120). What happens is the Killawatt starts beeping, since it can't measure > 15A. Again, I couldn't calc the exact wattage since both voltage and current were fluctuating, and I could read only 1 at a time, but it was somewhere in the vicinity of 17A.
Unfortunately, I probably won't be able to do any more testing, because it appears that Edison has finally gotten around to fixing my low voltage. I complained to them, and it looks like they fixed it, because as of yesterday, my voltage is around 122V in the morning, and doesn't drop below 118V.