RustyShackleford wrote:Newbie here, wife is about to by a used 2018 Leaf. I'm a little confused about the Level2 charging. Nissan says that using an L2-EVSE charging cable, it will charge the 40kwh version in 8 hours, which is a net of 5000 watts. But they also say you need to install a 50amp/240v outlet. That's 12000watts. I understand that outlets (over-current protection devices, specifically) need to be oversized, and that there's some inefficiency in the charging circuit. Still 12000watts versus 5000watts seems a bit extreme. Against code even, as breakers aren't supposed to be drastically larger than the expected load (I forget what the factor is, but it's a lot less than 2.4x). Please help me to understand.
OK, There are a lot on nuances in this equation. The EVSE (that's the cord you plug into the wall and the car) has a 14-50 plug on it, which nominally means a 50a circuit. The EVSE itself is able to supply 32a of current. Finally the car has a maximum draw of 27.5a. 240v * 27.5a = 6.6kW then knock a few percent off for charging inefficiencies (5-7%) and you're close enough to your 5000W estimate.
So why does Nissan seem to require a 50a circuit? Technically, the circuit must be 125% of the EVSE capacity. This means you could get by with a 40a circuit. Indeed, I have a setup exactly like that and it's pretty common. However, ask most electricians to put in a 14-50, and they'll do a 50a circuit unless there's a reason to do it differently...and I recommend that you do so unless there's a technical or economic reason to put in the smaller 40a circuit.