lincomatic
Well-known member
- Joined
- Jun 10, 2011
- Messages
- 316
chris1howell lent me his DIY EVSE so I could debug my new firmware for it.
Last night, I was playing with the pilot duty cycle. I set it to 14A and plugged it into 120V.
My KillAWatt showed that it was drawing between about 13.2 and 13.9A. I ran it that way for over 1/2 hour.
This afternoon, I plugged it in again, this time with both the KillaWatt and a current clamp ammeter.
I heard some beeping while I was at the car, and realized that the KillaWatt was complaining of overcurrent.. it was also flashing its display.
It was reading 16.3A!! The current clamp reads about .5A higher, and it was reading 16.8A!
I unplugged the KillaWatt and used only the current clamp, and this time, it was drawing about 17.5A.
I only ran it for a couple of minutes before turning it off.
Very strange, because the pilot was still set to 14A.
There are two possible explanations factors that I can think of for the inconsistency: 1) it was extremely hot outside this afternoon... the car had been baking in the sun for several hours at 95F+ 2) our pilot is out of spec currently, because the op amp we're using is too slow. The J1172 spec wants a rise/fall time of 2us, and currently, we're way off at about 40us. But this still doesn't explain why I was able to consistently charge at around 14A on 2 different occasions spaced several hours apart.
I decided to wait until the outside temperature cooled off tonight. When I plugged it in, it charged at 15A this time.
Next, I bumped the pilot up to 16A, and the car drew 13A.
Next, I tried 15A, 18A, 14A in that sequence, and the car drew ~12A in all cases!
I tried 6A, and the car refused to charge.
I tried 10A, and the car drew about 8.5A.
Now, the car is charging ~12A again regardless of my settings at 14A,15A,16A.
Very inconsistent. I don't know how to explain it, except that maybe the car is getting confused by the slow rise time of my pilot.
I'm a bit disappointed .. I had visions of charging the car @ 16A on 120V.
Last night, I was playing with the pilot duty cycle. I set it to 14A and plugged it into 120V.
My KillAWatt showed that it was drawing between about 13.2 and 13.9A. I ran it that way for over 1/2 hour.
This afternoon, I plugged it in again, this time with both the KillaWatt and a current clamp ammeter.
I heard some beeping while I was at the car, and realized that the KillaWatt was complaining of overcurrent.. it was also flashing its display.
It was reading 16.3A!! The current clamp reads about .5A higher, and it was reading 16.8A!
I unplugged the KillaWatt and used only the current clamp, and this time, it was drawing about 17.5A.
I only ran it for a couple of minutes before turning it off.
Very strange, because the pilot was still set to 14A.
There are two possible explanations factors that I can think of for the inconsistency: 1) it was extremely hot outside this afternoon... the car had been baking in the sun for several hours at 95F+ 2) our pilot is out of spec currently, because the op amp we're using is too slow. The J1172 spec wants a rise/fall time of 2us, and currently, we're way off at about 40us. But this still doesn't explain why I was able to consistently charge at around 14A on 2 different occasions spaced several hours apart.
I decided to wait until the outside temperature cooled off tonight. When I plugged it in, it charged at 15A this time.
Next, I bumped the pilot up to 16A, and the car drew 13A.
Next, I tried 15A, 18A, 14A in that sequence, and the car drew ~12A in all cases!
I tried 6A, and the car refused to charge.
I tried 10A, and the car drew about 8.5A.
Now, the car is charging ~12A again regardless of my settings at 14A,15A,16A.
Very inconsistent. I don't know how to explain it, except that maybe the car is getting confused by the slow rise time of my pilot.
I'm a bit disappointed .. I had visions of charging the car @ 16A on 120V.