120 Trickle Charge - How many amps?

[garygid]

I suspect that the 12A values in these specs are just "nominal" values,
not an exact statement of a maximum current drawn from the wall.

 

[DaveEV]

I doubt that there will be much ramping down on a L1 charge - it's only 1440W max into a pack that holds 24 kW - that's a C/17 charge rate - the pack will hardly notice.

I expect to see a taper at the end of charge.

Once the first cell in a series pack of cells reaches maximum charge (4.2v or whatever), the charger has to stop putting current through that cell, while still charging the other cells in series. This is needed to balance the charge levels of the individual cells.

Again - it's highly unlikely that the Leaf will be charging the packs to very close to a real "100%" charge. Doing so puts a lot of extra stress on the batteries which which degrade lifetime.

Unfortunately, we don't know exactly how the Leaf's BMS works or the real/used capacity of the cells - would be nice to know.

So it's no so much that the battery can't handle C/17 to capacity, but that the balancing stage can probably handle much less.

Unless the batteries start developing some serious differences in internal resistance (which would indicate that one or more modules is failing) - once they are balanced the first time, additional balancing requirements per charge should be minimal.

 

[wwhitney]

Mitch is right, 14 gauge wire simply cannot carry more than 15 amps, regardless of the length, if you try the wire will melt and cause a fire hazard. See ampacity chart here, http://www.cerrowire.com/default.aspx?id=46

I'm afraid that's not quite true. According to the NEC (Table 310.16), the ampacity of 14 gauge copper wire (for up to 3 conductors in a 30C ambient temperature) is 20 amps for 60C, 20 amps for 75C, and 25 amps for 90C. "Ampacity" is the maximum current the wire can carry while staying under the specified maximum temperature (the temperature rating of the insulation on the wire). So unless you coil your wire up very tightly, 15 amps will not melt insulation on a 14 gauge copper wire.

Now there is a separate rule in the NEC, 240.4(D), which imposes additional requirements on "small conductors". That rule limits the breaker size on a circuit using 14 gauge copper wire to 15 amps for "most" circuits. This is what is familiar to most people and is incorporated into the chart at the above website.

Lastly, all of this is for building wire, which is the permanently installed wiring in a building. The rules for cords and for appliance wiring are different and generally more lenient.

Cheers, Wayne

 

[GaleHawkins]

11 years later I am looking at hook it up a small solar system to charge a 2016 leaf and thanks for everybody's input. I was trying to figure out how much output from an inverter I need to use the 120 volt OEM charger. Thanks

 

[goldbrick]

I think the nominal input power for a 2016 OEM EVSE is 1.44 kW since it is made for a 15A circuit and 80% of 15A is 12A and 12A * 120V = 1.44 kW. The current should be well controlled so you shouldn't have to worry about surge current, etc.

 

[LilSparky]

Using a "P3 P4400 Kill A Watt Electricity Usage Monitor" I get 11.86 amps on my 2021 SL Plus with the included EVSE. I have seen others as low as 10.6 Amps.

 

[LeftieBiker]

Using a "P3 P4400 Kill A Watt Electricity Usage Monitor" I get 11.86 amps on my 2021 SL Plus with the included EVSE. I have seen others as low as 10.6 Amps.

How long did you leave it connected? The EVSE may ramp up a bit.