Any advantage of Level 2 vs Level 1 charging other than time?

Is there any advantage of using a Level 2 EVSE instead of using your household 110 plugs (Level 1) other than the fact that the Level 2 is faster?

I thought I heard that it is better to use Level 2 because every time you charge the battery, heat is generated and that wears on the battery so if you can charge it quicker, it is better for the battery.

I just purchased a 2013 Leaf this past Saturday so I'm trying to figure out the best way to take care of it.

L2 charging is a bit more efficient than L1 charging due to the constant ~300W draw by the cooling pump uses when charging in either mode.

Also, IMO, L2 charging is a little safer. The 120VAC plugs are not locking and are likely to get worn out over time and with the heating that comes with use. In fact, some 120VAC plugs are very low quality and my not do well at all with EV charging. At least one fire has been reported on this forum through the use of a 120VAC outlet.

By contrast, the outlet that I plug my L2-upgraded EVSE into has a locking connector which holds the plug firmly in place. Many others here have a hard-wired L2 EVSE, which is safer still.

Level 2 charging is much more efficient. I don't recall the numbers for the Leaf offhand but in my Rav4-EV level 2 is about 80% efficient while level 1 is about 66%. Over a typical 12,000 mile year that efficiency difference could amount to about 1,000 extra kWh consumed.

I don't think there's much to the time-spent-charging angle, especially since the amount of heat generated at level 1 would be very low. The other big factor would be if you're on a time-of-use electric rate (as you should be) which could mean that you won't have enough time to fully charge the car at level 1 during the cheapest rate window.

I will give a different perspective.

My friend has a leased 2014 LEAF and he uses L1 charger.

I have a second hand 2012 LEAF that I use the L2 charger. My battery has degraded a lot compared to his, but, I put more number of miles on the car. I have noticed that using the L2 charger, I am able to take way more trips over the weekend/weekdays than he normally would after returning from work. This has enabled me in using the gas Ody less and less. I have cut down on at least 40 percent of my other gas car that would normally be used.

I have to question whether installing a locking receptacle outlet for use with an EVSE is preferable to that of a straight blade outlet. My understanding is that locking receptacle outlets are designed mainly for use when there is vibration (like on generators), and that otherwise it is considered more desirable that a plug pulls out of a receptacle under moderate/heavy force rather than risk ripping the receptacle/wiring apart.

I know of no major name electrical company's plug and cord EVSE that provides a plug for use with a locking receptacle.

Tesla's Mobile Connector EVSE for its Model S currently only uses 4 (proprietary) plugs, all straight blade (NEMA 5-15, 5-20, 10-30, and 14-50).

Tesla's Universal Mobile Connector for the Roadster provides for 6 additional (proprietary) plugs, but only the NEMA L14-30 one is locking -- and it is described by Tesla documentation for use with generators.

BTW examining the contact surfaces of common receptacles, I can't see a clear advantage of a locking receptacle over its straight blade equivalent. (IMHO if ever a plug starts pulling out of a receptacle too easily, then is the time to replace the receptacle.)

So my take is that a wall outlet intended for permanent or frequent use with a portable EVSE should be of straight blade design.

I have had my Leaf (2015) for a week now, my EVSE charger has not come in yet, so I use the 120V trickle charger provided with the car until my EVSE Charger is up and running.

The question I have, is it even possible to get to 100% charge (from the Leaf instrumentation point of view) with the 120V charger?
I have come in multiple times in the morning to find that the charge is off (both car lights and the charger cable indicator light) and when I check the SOC it is at 97 - 98%.

Since I'm a newby, is that normal? Is it related to the 120V charger?
I have done 3 or 4 quick charges any where from 50 - 80% (meaning I added 50 - 80% to my charge)... would that play a role?

I regularly get 100% charge with my level 1 EVSE.

Well, that is not promising. Thanks for the quick feedback.

We're still using 120V with the trickle charger. I had the same issue of the car not charging to 100% a few times. I guess the issue was heat buildup in the outlet and this tripped the 15 amp GFCI breaker, which itself was 32 years old. A new 15 amp standard breaker and several new GFCI outlets solved the issue. It turns out the wiring for this circuit runs app. 60 feet from the circuit breaker up through two bathroom outlets before going into the garage. Low quality push-in wiring for pass-through on the old outlets too. I haven't had a problem since replacement.

I understand why they recommend a dedicated circuit for electric vehicle charging: old houses and sub-par wiring.

mspisars said:

The question I have, is it even possible to get to 100% charge (from the Leaf instrumentation point of view) with the 120V charger?
I have come in multiple times in the morning to find that the charge is off (both car lights and the charger cable indicator light) and when I check the SOC it is at 97 - 98%.

Click to expand...

I have a 2015 as well, and noticed this same thing where I'm plugged in with the Level 1, and it stops charging around 96%(as shown on the SOC guage) for me. The charging lights on the car as well as the charge light on the EVSE are off. No breakers or GFCI have been tripped, and I am not using any remote climate controls. I wonder if this is something new with the 2015 battery that doesn't allow trickle charging to 100%. I've had no issues with L2 charging to 100% on the SOC display.

In my 2011 after the P3227 update my car won't charge all the way (% charge as measured from LeafSpy and "all the way" meaning ~96% since the 2011 only has bars on the dash) if I start from a relatively high SOC (60-90% perhaps). This is incredibly annoying, as with my severely degraded battery I really need every drop of charge possible to get to work and back, but if I do light driving over the weekend the car won't charge up all the way Sunday night.

I have no idea how the 2015 operates, but perhaps something similar is in effect. For those that only charged up to the high 90s, do you recall what you starting SOC was? If you can, drive the car down as low as possible before doing a complete charge and see if that gets you all the way to "100%".

jjohnsonwbc said:

Is there any advantage of using a Level 2 EVSE instead of using your household 110 plugs (Level 1) other than the fact that the Level 2 is faster?

I thought I heard that it is better to use Level 2 because every time you charge the battery, heat is generated and that wears on the battery so if you can charge it quicker, it is better for the battery.

I just purchased a 2013 Leaf this past Saturday so I'm trying to figure out the best way to take care of it.

Click to expand...

If you are looking for hard numbers see http://www.mynissanleaf.com/viewtopic.php?f=9&t=19899 (efficiency of 3.x KW charger vs 6.x KW charger on 120V/240V)

dhanson865 said:

http://avt.inel.gov/pdf/fsev/SteadyStateLoadCharacterization2012Leaf.pdf" onclick="window.open(this.href);return false;

It surprised me that L1 120V charging is way more efficient on the 3.3/3.8 KW charger than it is on the 6.0/6.6 KW charger.

It also appears the sweet spot for L2 charging the 3.3/3.8 KW efficiently is between 8A@240V for 1.9 KW input to 12A@240V for 2.9KW input. If you have 208V instead make it 10A@208V for 2.1KW to 14A@208V for 2.9KW. The power factor at this sweet spot is .98 vs the .99 at full load but I'm thinking the efficiency gain is enough to offset that even if you are billed on apparent power.

L2 on the 6.0/6.6 KW charger is most efficient at full load. Give it a 30+ Amp EVSE and let it pull all it can.


Oh and all the testing was done at 208V. I'm assuming efficiency will improve at 240V and keep the same general shape of the curve but I might be wrong about the exact peak of the curve using that assumption.

Click to expand...

fwiw I'm charging my car at home at 12 amps selected on an openevse and it shows 11.5 x 240v for about 2.8KW with leafspy showing 2.5KW making it to the battery (in .1 KW increments its imprecise for figuring out actual efficiency).

You might notice I say 3.x KW instead of picking 3.3 KW, 3.6 KW, or 3.8 KW.

Nissan Connect(sm) EV (Carwings) shows it labeled as

Approximate time to charge
Trickle 10 hrs 0 min
Normal 3.6 kW 4 hrs 30 min
Normal 6.6 kW

So they've changed the way they describe the charging speeds yet again. I just call it 3.x KW, it's easier that way.

veezer said:

mspisars said:

The question I have, is it even possible to get to 100% charge (from the Leaf instrumentation point of view) with the 120V charger?
I have come in multiple times in the morning to find that the charge is off (both car lights and the charger cable indicator light) and when I check the SOC it is at 97 - 98%.

Click to expand...

I have a 2015 as well, and noticed this same thing where I'm plugged in with the Level 1, and it stops charging around 96%(as shown on the SOC guage) for me. The charging lights on the car as well as the charge light on the EVSE are off. No breakers or GFCI have been tripped, and I am not using any remote climate controls. I wonder if this is something new with the 2015 battery that doesn't allow trickle charging to 100%. I've had no issues with L2 charging to 100% on the SOC display.

Click to expand...

The L1 EVSE has a temperature sensor built into the plug itself, so if the outlet is overheating from extended use, it will shut down for safety reasons or reduce power to the car. If the outlet is running hot, then the power level is probably too low to finish charging. A simple experiment would be to plug into another outlet or use a heavy duty extension cord from another outlet to see if the charging issue goes away. If you can get a 100% charge from other outlets, then the one you are using might be on an overloaded circuit, sub-par or old wiring as mentioned earlier.

jjohnsonwbc said:

I thought I heard that it is better to use Level 2 because every time you charge the battery, heat is generated and that wears on the battery so if you can charge it quicker, it is better for the battery.

Click to expand...

You are thinking of this wrong. Heat is generated within the battery as a function of the current going in. The battery has some internal resistance, "R". Power is defined as P = I^2 * R, where I is the current through the resistor, and not the current from the wall.

L2 charging is roughly 3-6x faster than L1 (depending on whether you have a 3.x kW or 6.6 kW charger). So the current going into the battery is 3-6x higher, since the battery voltage is the same either way.

Given that, the power within the battery is 9-36x higher when L2 charging, although it only lasts 1/3-1/6 as long.

If I haven't lost you yet, the bottom line is that L2 charging will produce 3-6x as much heat within the battery as L1 trickle charging. So if you are really concerned with minimizing battery heating, L1 is the way to go.

Personally, I try to only use L1 in the summer, when the battery temp reads 6-7 bars.

I needed the time (L1 was too slow for my commute), but the other real benefit was just ease-of-use.

Having a wall mounted unit I can just have always connected to power and plug in and easily unplug and use is much nicer than using the L1. I could have left it all plugged it in I suppose, but wasn't sure it was designed for that...

Also, if I were going to do an L1 all the time, I'd still want to make sure it was a good dedicated (safe) connection. If I'm going to all that trouble, then I might as well do L2.. ;-)

desiv

mspisars said:

I have had my Leaf (2015) for a week now, my EVSE charger has not come in yet, so I use the 120V trickle charger provided with the car until my EVSE Charger is up and running.

The question I have, is it even possible to get to 100% charge (from the Leaf instrumentation point of view) with the 120V charger?
I have come in multiple times in the morning to find that the charge is off (both car lights and the charger cable indicator light) and when I check the SOC it is at 97 - 98%.

Since I'm a newby, is that normal? Is it related to the 120V charger?
I have done 3 or 4 quick charges any where from 50 - 80% (meaning I added 50 - 80% to my charge)... would that play a role?

Click to expand...

VERY new here (5 days ownership, 2015S, 6.5k miles. I've trickle-charged it 4 nights in a row, to 100%.

gncndad said:

mspisars said:

I have had my Leaf (2015) for a week now, my EVSE charger has not come in yet, so I use the 120V trickle charger provided with the car until my EVSE Charger is up and running.

The question I have, is it even possible to get to 100% charge (from the Leaf instrumentation point of view) with the 120V charger?
I have come in multiple times in the morning to find that the charge is off (both car lights and the charger cable indicator light) and when I check the SOC it is at 97 - 98%.

Since I'm a newby, is that normal? Is it related to the 120V charger?
I have done 3 or 4 quick charges any where from 50 - 80% (meaning I added 50 - 80% to my charge)... would that play a role?

Click to expand...

VERY new here (5 days ownership, 2015S, 6.5k miles. I've trickle-charged it 4 nights in a row, to 100%.

Click to expand...

I have a 2015 as well, and my only way of charging the car is L1. I have been able to charge to 100% multiple times, but then again I do not have the LeafSpy app to ensure it is 100%

To the car, 120v (L1) is the same as 240v (L2), it will not make any difference on how long the car will last. HOWEVER - TIME is the answer to the L2 question.... I used my L1 charger for 5 months before I got the L2. I would drive 50 miles round trip to work (end up at around 40% charge), and at 3pm, I would have to leave the car plugged in overnight to charge for the next day! I did not have use of the car for the rest of the night!. BUMMER>

With the L2, the car charges at 6-7x that rate. I get hone at 3pm, plug in, and at about 5-6pm, I have another 100% charge to use for the evening driving. Much more use of the car! Do not hesitate and get the L2 if you want to charge more than once per day.

Also, I understand that electrically, you will use less electricity from your meter with the 240 volt charger because it is more efficient.