Going into my first winter with home charging and have been thinking a lot about the interplay among charging, preheating, Time of Use Rates, and so on.
My Wall Connector is set up for 40 amps, which is all my car can use for charging.
It is my understanding that, when preheating, the car allocates some of the charging capacity to the cabin and/or battery heaters. If the two heaters are both on, it looks as if that could take the full 40 amps (or more if it were available).
But it occurred to me that the WC can deliver up to 80 amps for cars that can accept it, so the box itself and the cable and connectors can obviously handle that current. And when preheating, the car needs as much as 11 or 12 KW for the battery and cabin heaters, as I understand it. (I have seen conflicting figures in this forum for the KW ratings of the heaters, but they seem to be in that neighborhood.)
So, practical question: If the WC were on a circuit that can deliver more than 40 amps, say 72 or 80 amps, could the car use that excess capacity for preheating so that the full 40 amps can be used for charging? And if not, wouldn't that be an advantage? I do not see any discussion of this point in the WC installation instructions as a basis for choosing what capacity your circuit should be.
Probably this has been addressed in past posts but a few minutes did not turn up the answer. Discussion I have seen seems to imply that the car will limit the current to the maximum allowed for charging, without any allowance for the heaters. That seems to be a big disadvantage in cold climates....
My Wall Connector is set up for 40 amps, which is all my car can use for charging.
It is my understanding that, when preheating, the car allocates some of the charging capacity to the cabin and/or battery heaters. If the two heaters are both on, it looks as if that could take the full 40 amps (or more if it were available).
But it occurred to me that the WC can deliver up to 80 amps for cars that can accept it, so the box itself and the cable and connectors can obviously handle that current. And when preheating, the car needs as much as 11 or 12 KW for the battery and cabin heaters, as I understand it. (I have seen conflicting figures in this forum for the KW ratings of the heaters, but they seem to be in that neighborhood.)
So, practical question: If the WC were on a circuit that can deliver more than 40 amps, say 72 or 80 amps, could the car use that excess capacity for preheating so that the full 40 amps can be used for charging? And if not, wouldn't that be an advantage? I do not see any discussion of this point in the WC installation instructions as a basis for choosing what capacity your circuit should be.
Probably this has been addressed in past posts but a few minutes did not turn up the answer. Discussion I have seen seems to imply that the car will limit the current to the maximum allowed for charging, without any allowance for the heaters. That seems to be a big disadvantage in cold climates....