StrangerTides said:
For me this is more questions than answers - why call the utility? To find out if they support this time-of-use business so we can pay less for off-peak electricity? Is that also the only reason for the sub-meter and second panel? Which Leviton makes sense under what conditions? Shouldn't the electrician know all this or do I need to educate myself so I can educate them? Is the 6.6kW what's called the "level 2" charger elsewhere on the forum? Is this the $700 "quick charge" option only available on the SL model?
Good questions; sorry this wasn't clear; I agree it wasn't so let's fix that.
a) I want to take advantage of Dominion Virginia Power's Time Of Use (TOU) rates to charge my EV. The {rate} Schedule 1T is very attractive. However, I want my household to use the standard fixed-rate (seasonal) {rate} Schedule 1. Thus, I want to keep my existing electrical meter
and add a sub meter (dual-meter) which measures the TOU usage.
FYI, I have already called my Utility and they said this was possible. Yours may be different, thus YMMV. The utility did not tell me if they would do any of the work to install the second meter, though, so I figured I'd call a local electrician to see what this would entail and the local contractor would better know how to deal with the utility and the county and the permitting and all the rest.
If I get a second meter, it is my understanding that I will need a second electrical panel.
b) Hopefully the electrician will know a bit about the subject, but there really isn't much to it and you may as well be informed. Basically, the LEAF comes with a 3.3kW charger. This means it can accept at most 30A (Ampères -- think of this a charge speed, a multiple of electrons per second) of electricity at 110V (Volts -- think of this as electrical force, how hard the wire is pushing on the electrons to move) of power (30A * 110V = 3.3kW) or 15A of electricity at 220V power (15A * 220V = 3.3kW). Now, 110V is what your standard U.S. electrical outlet runs at. But those plugs are typically only rated at 15A max. This, the 110V 15A charge is known as Level 1, or L1, charging.
Level 2, or L2, charging is any charge at twice the voltage of Level 1, i.e. 220V - 240V. As I just demonstrated, for Level 2 charging, the most current the LEAF can accept is 15A. However, this is a 220V circuit so it uses a different type of plug, typically a NEMA 6 or a NEMA 14 plug. The 14 plug (14-30R) is typically for most home dryers. The 14 refers to the shape of the plug (and specifically which includes a common wire, to get technical) as well as the 6 (which has no common wire) in 6-20R. The second number, before the R, is the maximum average current rating. For the dryer, a 14-30R, that's 30A. For the various Leviton devices, they have plugs which support 6-20R (20A), 6-30R (30A) and 6-50R (50A). Clearly, if the LEAF, with its 3.3kW charger could only accept at most 15A of current, the 6-20R Leviton unit should be quite sufficient to all your charging needs.
But I personally want my LEAF to have a 6.6kW charger. Mark Perry has said that this will be an available after-market upgrade on the LEAF (most recently on NPR's Science Friday about a month ago). I plan to get this upgrade when it becomes available. That means I need to have my Electric Vehicle Service Equipment (EVSE, e.g. the Leviton unit) to support at least 30A charging. The 6-30R unit should be enough for this in principle, and in fact, there is some rounding off and efficiency loss that I've glossed over that means the 6-30R is actually a pretty good fit for 6.6kW charging. However, if the price is reasonable, I'd just assume go with the maximum possible current (the 6-50R) to future proof the EVSE against not just a possible LEAF upgrade but against potentially even my next Electric Vehicle (EVSE). Either way, whether the LEAF is 3.3kW or 6.6kW this is all Level 2 charging since it is all at 220V - 240V.
In all the previous cases, those are alternating current, meaning that first the voltage pushes the electrons forward, then it pulls them backward then forward again in a sine wave at 60Hz. You don't need to know that detail, just remember that Level 1 and Level 2 are Alternating Current (AC). Quick charging is Direct Current (DC), meaning that the electrons are always pushed in one direction along the wire. Quick Charging uses DC. In fact, it uses DC at typically 440V - 480V electromotive force, which means the LEAF can charge really fast. This is quoted as about 30 minutes to go from 0% charge to 80% charge. It would take a lot longer to go from 80% charge to 100% charge using the DC circuit so this is usually not recommended. This DC connection is only available if you get the $700 Quick Charge option for the SL model.
Incidentally, Quick Charging is not the same as Level 3 charging since Level 3 charging is not standardized yet which is why some of us are nervous about trusting Nissan to guess correctly that the standard they use will become the official standard.
Hope that helps!
