EVDRIVER wrote:GerryAZ wrote:RegGuheert wrote:Agreed.
However, I will note that there IS a change in what happens at 120 VAC versus 240 VAC. Either the EVSE or the OBC or both needs to be programmed to limit the current at the lower voltages to 12A while it will have a higher limit for 240 VAC. As such, there is typically a blackout voltage somewhere between about 150 VAC and 180 VAC.
Since the new Nissan unit uses an adapter attached to the 14-50 plug, I expected that it would work like my welder and sense the presence of the adapter to switch to 120 volts. Also, the EVSE needs to change the pilot signal to correspond to 12 amperes to avoid overloading the supply circuit if it is used with a car capable of drawing higher current at 120 volts. I wish I could borrow one of these new units to test.
The adapter does not need to sense this it can be done via voltage. They also may have a hard limit below 240V at some point to insure cut off for brown outs. Some EVs will cut the charge with voltage sags and this may be a crude way to detect this without that change from 240 to 208 although that would be easy. It also may be there for other reasons. Without testing it is not easy to determine.
Yeah, they could have done it either way. Tesla uses a resister in the adapter because they need to tell the difference between different 240v adapters. I would have done the same thing here just to have a more positive indicator, and to have a more flexible design. However, assuming the device monitors voltage at all, which it almost has to in order to refuse to work on 208v, using a voltage cutoff would certainly work adequately for this design.
The point I wanted to make is that anyone who wishes to do a mod to fix this is likely to have to hack the firmware, not just the hardware.