solarman said:
Can someone please explain the Kw ratings on the 2013 LEAF onboard chargers. All the specs I've seen so far list ratings as 3.6 kW (3.3kW Output) for the 2013 S model and 6.6 kW (6.0 kW Output) on the 2013 SV and SL models. The Nissan Rep (not Tim, the other fellow) at the meeting in San Jose on Saturday told me that the 3.6kW on the 2013 S model is better/faster than the charger on the earlier 2011 and 2012 LEAF models. Is this a fact? What is the output on the 2011 onboard charger 3.3kW? 3.0kW? Is there a difference?
As far as we know, the 3.3kW charger will draw 16 amps for 3.8kW power draw from a 240 volt electrical supply in the USA/Canada. The charger will be exactly the same specification for 2011, 2012 and 2013. That doesn't mean that they are the same manufacturer, as the 2013 LEAF uses a different design and manufacturer.
I suspect that the optional 6.0kW charger is wrongly named for the USA/Canada North America market, since 30 amps at 200 volts (the Japanese standard) = 6.0kW. Commercial USA sites will use 208 volts, making 6.2kW. Residential USA voltage will be 240 volts pulling 7.2kW.
If it is pulling 30 amps at 240 volts, then we have a 7.2kW power draw from the electrical supply, which would equal approximately 6.3kW into the battery. No known J1772-2009 cables are rated for 32 amps in the North American market, making 30 amps the default current draw maximum for the 2013 LEAF.
In summary, 30 amps will draw 6.0kW at 200 volts in Japan and 6.2kW to 7.2kW in North America, depending on commercial or residential voltage service. In the rest of the world using 230 volts, this will be about 6.9kW from the electric supply.
Having said all that, just like the 3.3kW charger that pulls 3.8kW of power (86% of 3.8kW is 3.3kW), any of the above examples may have approximately 90% efficiency. Therefore, a "6.6kw" charger may pull about 7.2kW from "the wall".
Additionally, a 6.0kW charger may pull 6.6kW, however is will be at 27.5 amps at 240 volts. Why is this not probable? Because standards for continuous power through a circuit breaker are subject to a guideline of 80% of their respective rating. Circuit breakers for these types of uses are typically rated at nice even numbers; 10 amps, 15 amps, 20 amps, 30 amps, 40 amps, 50amps, etc.
So, 80% continuous load equals the following:
Circuit ---- 80% continuous
breaker ---- load
10 amps ---- 8 amps
15 amps ---- 12 amps
20 amps ---- 16 amps
30 amps ---- 24 amps
40 amps ---- 32 amps
50 amps ---- 40 amps
Do you see a trend here? The engineers are not going to specify a 27.5 amp unit, unless that was a limit. Ordinarily, they could make 32 amp units, but as I previously stated, there are not 32 amp rated J1772-2009 "nozzles" in the world. So, they make 12 amp, 16 amp, 30 amp, 40 amp, and 75 amp ones. Did you notice that nobody is making a 27.5 amp J1772 nozzle?
At 30 amps, the following applies:
Power --
Voltage --
at 88% efficiency into the battery
7.5kW ---- 250 ---- 6.6kW
7.2kW ---- 240 ---- 6.3kW
6.9kW ---- 230 ---- 6.1kW
6.2kW ---- 208 ---- 5.5kW
6.0kW ---- 200 ---- 5.3kW