Amperage to charge for Level 2

[docj]

I normally charge at 32 amps with a 40 amp breaker in my box with no problems whatsoever.

 

[cornbinder89]

I normally charge at 32 amps with a 40 amp breaker in my box with no problems whatsoever.

Of course, 32 amps is 80% of 40, and within the code. 27.5 amps on 30 amp circuit is not. If you are charging a leaf, the actual draw is going to be between 27 and 28 amps. unless the voltage is 208, then might be as high as 30.
Unless whoever installed that 30 amp dryer circuit "over wired" the gauge of wire by a lot, pushing 27.5 amps for a long time is going to make the cable between the circuit panel and the outlet get hot, and that isn't a good thing.
There is no "40 amp" NEMA size for a plug or outlet. NEMA jumps from 30 to 50, which is why I said what I did. If you are hard wiring than you can use wire and CB for 40 amps. If you are using a plug it needs to be wired and CB for 50 amp. You should not use a 50 amp outlet with lighter 40 amp wire and CB.

 

[RYoungberg]

Hey there, wondering about the charging at home. But doing some watching and reading and my overall thought is that the lower amperage that you can have for charging is better for the battery. For example, I can have a 50 amp breaker on my level two but I decided to go with a 20 amp breaker. My rationale is simply for a slower charge being easier on the battery. I’m even contemplating using a 120 for a 24 hour charge. I’m at home and can simply plan when I have to drive and need a quicker charge. I’m also in eastern Canada and get cold winters so my rationale is that if I can keep it concert charge on the battery it’ll keep it warm, since we know the leaf has no battery heating. What do you think? Am I out to lunch on this? Cheers.

My son's 2014 LEAF has only been charged with a 120V outlet. It has 85,000 miles and 95% battery. I think there is something to be said for the 'trickle charge' appoach.
However, your proposal to use a 20 amp circuit breaker with a 30 amp load from the LEAF may cause some serious electrical problems?
Cheers!

 

[Steve52]

Just wondering re "over 24 amps but less than 40, needs a 50 amp plug", etc. Is this "best practice" or is there some other reason? I have been using the supplied charger on a regular 30A dryer outlet for over a year now. I measure a 27A draw.

If you're going to continue to use the 30 Amp dryer plug instead of a new, dedicated 40 or 50 amp circuit, it would best practice to use an adjustable EVSE model that can be set to 24 amps or lower; 30 amps x 0.80 = 24 amps. "Best practice" isn't just some casual advice, it's a safety issue and if not followed can degrade your wiring and other electrical components over time. No more stressed wires and peace of mind for a few hundred dollars over the long term.

 

[goldbrick]

Also, don't think there is a designated NEMA 40A plug so once you're over 30A it's either a hard-wired connection or a 50A plug.

There is even an exception that you can use a 50A plug on a 40A circuit but I wouldn't recommend that, although a 27A load from a dedicated EVSE would be one obvious application that could use that setup.

edit to add: just saw some other posts above so sorry if some of this is a repeat.

And, I've read here from a reliable source that the 80% rule is mostly used to prevent 'nuisance' trips of the breaker in the circuit, not for the wire per se. The operating temperature of the wire depends on a lot of things, including its length and how much air flow it gets. The connections are the usually the weakest point in the circuit since they can get loose due to thermal cycling and then cause arcing if loose enough.

 

[RYoungberg]

Of course, 32 amps is 80% of 40, and within the code. 27.5 amps on 30 amp circuit is not. If you are charging a leaf, the actual draw is going to be between 27 and 28 amps. unless the voltage is 208, then might be as high as 30.
Unless whoever installed that 30 amp dryer circuit "over wired" the gauge of wire by a lot, pushing 27.5 amps for a long time is going to make the cable between the circuit panel and the outlet get hot, and that isn't a good thing.
There is no "40 amp" NEMA size for a plug or outlet. NEMA jumps from 30 to 50, which is why I said what I did. If you are hard wiring than you can use wire and CB for 40 amps. If you are using a plug it needs to be wired and CB for 50 amp. You should not use a 50 amp outlet with lighter 40 amp wire and CB.

When I ran 240V service for my 2019 LEAF the specs clearly said 50 amps.
NEC recommends using 6 AWG copper and 4 AWG aluminum wires for cable distances of 100 feet or less. My run was about 60 ft.
ICYMI - The NEC - National Electric Code, is a safety standard that describes safe electrical installation methods. It's the primary electrical installation code in the United States, and is used by most states, municipalities, and cities.
I had tried my 240V 30 amp dryer outlet a couple times but the LEAF onboard charger shut down after a short time, the circuit breaker did not flip.
A typical dryer has a 30 amp service with 10 AWG wire. Using a dryer outlet to charge your LEAF is NOT a good idea for both the LEAF and your safety!

 

[Stanton]

A typical dryer has a 30 amp service with 10 AWG wire. Using a dryer outlet to charge your LEAF is NOT a good idea for both the LEAF and your safety!

Actually, it's a great idea if you used properly! I guess you didn't read the @Steve52 post above?
Don't spread FUD just because something doesn't work for you.

 

[cornbinder89]

Just wondering re "over 24 amps but less than 40, needs a 50 amp plug", etc. Is this "best practice" or is there some other reason? I have been using the supplied charger on a regular 30A dryer outlet for over a year now. I measure a 27A draw.

Actually, it's a great idea if you used properly! I guess you didn't read the @Steve52 post above?
Don't spread FUD just because something doesn't work for you.

RobK's post was what he was refering too, and no used that way is not a good idea. It is why the factory duel voltage EVSE has a 50 amp plug on it and not a 30.
No problem if using a variable rate charger set to 24 or less, but that was not what Ryoungberg was refering to, at least the way I see it.