l6sman
Posts: 8
Joined: Fri Dec 04, 2020 4:35 pm
Delivery Date: 04 Dec 2020

Re: Installing 4-prong charger on 3-wire 240V distribution

Sat Dec 26, 2020 11:30 am

GerryAZ wrote:
Fri Dec 25, 2020 4:45 pm
l6sman wrote:
Fri Dec 25, 2020 11:25 am
DaveinOlyWA wrote:
Fri Dec 25, 2020 10:13 am


First off; Don't use your setup, its dangerous. You can't run more than 24 "amps" on your dryer connection.

2nd off; I am hoping your testing the garage door opener and whatever else is simply ignorance as there can be NOTHING else sharing that circuit.

3rd off; I use my dryer plug on a splitter with the adapter as well and it works fine one at a time. I use a Clipper Creek 24 amp EVSE.
Well, I'm not using a dryer plug per se, I have a dedicated 30 amp circuit breaker and I installed a new dryer plug off of that. The only thing running on that circuit will be my charger. However, I only have 30 amps total going to my garage. When I set I tested the lights and garage door i was checking to see if they plus the Nissan charger were drawing more than 30 amps because I would assume that would trip my breaker but it didn't. That's why I was wondering if the Nissan charger has some intelligence in it so that it doesn't draw more than is available. The manual says it draws a continuous 30 amps. If that was the case then I would've thought that turning on lights or opening my garage door would've trip the circuit. The new SplitVolt charger only draws 24 amps so it should be fine. I am just wondering about the Nissan charger.
If the circuit to your garage is only sized for 30 amperes total, then there could be enough voltage drop to cause the Nissan EVSE to fail--this would explain why it worked once if the system voltage was a little higher. The Nissan EVSE will allow the car to pull up to 30 amperes continuous so it needs a 40 or 50 ampere circuit. Also, the Nissan unit will shut down with error lights if it determines the voltage is too low. The Nissan EVSE that came with my 2019 will charge the car fine at my house on nominal 240V, but will not charge the car at my workshop on nominal 208V (typically 212 or 213 volts). It appears to be ready to charge with the EVSE plugged in to the 14-50 receptacle and will appear to start charging when the J1772 connector is plugged in to the car, but will shut down as soon as the car starts drawing current (probably because the voltage drops below its allowable threshold). If you have a 30-ampere circuit, then the "SplitVolt" unit which is rated at 24 amperes should be OK to use.


OK, thanks for the info. By the way the Nissan charger did not quit working, that's what I assumed it must have some built-in intelligence and be charging at less than 30 amps. The Splitvolt one malfunctioned but it may have been bad from the factory. I have a new Splitvolt one that I am trying out now :)
Other posts in this thread imply that the maximum current the car will draw is 27.5 amperes, but that is not correct. My 2015 would draw 30 amperes when charging from a nominal 208V circuit (typically 212 or 213 volts). The current draw from a nominal 240V circuit would vary with voltage (lower current at higher voltage), but I never saw it above 27.5 because the voltage at my house never got low enough to have the current increase above that level. As an example, the last charge before trading in was 26.6 amperes at 243.3 volts. My 2019 draws a little more current than the 2015: 27.6 amperes at 244.2 volts, 27.0 amperes at 246.1 volts, 26.8 amperes at 250.1 volts, or 28.6 amperes at 236.3 volts. The 2019 will draw a little over 30 amperes when charging from a 208V nominal circuit if the EVSE pilot signal will allow. My Clipper Creek EVSE at my workshop garage allows 40 amperes and I saw 30.4 amperes at 214.3 volts the first time I charged there.

dmacarthur
Posts: 212
Joined: Tue Jul 03, 2018 4:00 pm
Delivery Date: 03 Jul 2018
Leaf Number: 306556
Location: Vermont

Re: Installing 4-prong charger on 3-wire 240V distribution

Sat Dec 26, 2020 6:08 pm

So, I have a question relative to this: My power company will sell me power at a reduced rate off-peak if I install a wi-fi EVSE (it has to be a ChargePoint Flex Home, adjustable), and the instructions are clear that it CAN be plugged in if used at the higher amperages (40 or 50) but can not be plugged in, has to be hard wired, if being used at the lower amperages (in my case, 24). This makes no sense to me but someone here will have an idea I am sure....
2015 Leaf sold
2019 Leaf Plus S as of 9/30/19

goldbrick
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Leaf Number: 311806
Location: Boulder, CO

Re: Installing 4-prong charger on 3-wire 240V distribution

Sat Dec 26, 2020 6:54 pm

You're right, that doesn't make sense. The only thing I can think of is that the unit comes with a 50A plug and if it is going to be used on a lower rated circuit (eg 30A), you must remove the plug and hard-wire it. I don't know why you couldn't just replace the plug but maybe ChargePoint doesn't want to support someone putting on all kinds of various plugs on their units.

Edit to add: or maybe it only has a UL rating for those configurations.
Last edited by goldbrick on Sat Dec 26, 2020 7:21 pm, edited 1 time in total.

LeftieBiker
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Re: Installing 4-prong charger on 3-wire 240V distribution

Sat Dec 26, 2020 7:00 pm

I just woke up, but I suspect they don't want you to just unplug it and sell it, after getting the lower rate. Can they track it themselves?
Scarlet Ember 2018 Leaf SL W/ Pro Pilot
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dmacarthur
Posts: 212
Joined: Tue Jul 03, 2018 4:00 pm
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Re: Installing 4-prong charger on 3-wire 240V distribution

Sun Dec 27, 2020 4:58 am

LeftieBiker wrote:
Sat Dec 26, 2020 7:00 pm
I just woke up, but I suspect they don't want you to just unplug it and sell it, after getting the lower rate. Can they track it themselves?
I am buying the unit myself since the program came along after I bought the Leaf, so re-selling is not the issue. As Goldbrick points out, the plug-in cable that comes with it is larger than needed for the lower charging rates, but I can not see this as a safety issue (unless someone sees the larger cable and plug and decides to up the amperage without checking the rest of the system?). I live thousands of feet off into the woods and no one is ever going to come along and do that......

As for the electricity tracking, yes they will have wifi access to the EVSE unit I suppose to verify that only the power they consider off-peak gets the lower rate- since I only charge between 12 and 4 AM this should be pretty safe.
2015 Leaf sold
2019 Leaf Plus S as of 9/30/19

l6sman
Posts: 8
Joined: Fri Dec 04, 2020 4:35 pm
Delivery Date: 04 Dec 2020

Re: Installing 4-prong charger on 3-wire 240V distribution

Sun Dec 27, 2020 7:42 am

l6sman wrote:
Sat Dec 26, 2020 11:30 am
GerryAZ wrote:
Fri Dec 25, 2020 4:45 pm
l6sman wrote:
Fri Dec 25, 2020 11:25 am


Well, I'm not using a dryer plug per se, I have a dedicated 30 amp circuit breaker and I installed a new dryer plug off of that. The only thing running on that circuit will be my charger. However, I only have 30 amps total going to my garage. When I set I tested the lights and garage door i was checking to see if they plus the Nissan charger were drawing more than 30 amps because I would assume that would trip my breaker but it didn't. That's why I was wondering if the Nissan charger has some intelligence in it so that it doesn't draw more than is available. The manual says it draws a continuous 30 amps. If that was the case then I would've thought that turning on lights or opening my garage door would've trip the circuit. The new SplitVolt charger only draws 24 amps so it should be fine. I am just wondering about the Nissan charger.
If the circuit to your garage is only sized for 30 amperes total, then there could be enough voltage drop to cause the Nissan EVSE to fail--this would explain why it worked once if the system voltage was a little higher. The Nissan EVSE will allow the car to pull up to 30 amperes continuous so it needs a 40 or 50 ampere circuit. Also, the Nissan unit will shut down with error lights if it determines the voltage is too low. The Nissan EVSE that came with my 2019 will charge the car fine at my house on nominal 240V, but will not charge the car at my workshop on nominal 208V (typically 212 or 213 volts). It appears to be ready to charge with the EVSE plugged in to the 14-50 receptacle and will appear to start charging when the J1772 connector is plugged in to the car, but will shut down as soon as the car starts drawing current (probably because the voltage drops below its allowable threshold). If you have a 30-ampere circuit, then the "SplitVolt" unit which is rated at 24 amperes should be OK to use.


OK, thanks for the info. By the way the Nissan charger did not quit working, that's what I assumed it must have some built-in intelligence and be charging at less than 30 amps. The Splitvolt one malfunctioned but it may have been bad from the factory. I have a new Splitvolt one that I am trying out now :)
Other posts in this thread imply that the maximum current the car will draw is 27.5 amperes, but that is not correct. My 2015 would draw 30 amperes when charging from a nominal 208V circuit (typically 212 or 213 volts). The current draw from a nominal 240V circuit would vary with voltage (lower current at higher voltage), but I never saw it above 27.5 because the voltage at my house never got low enough to have the current increase above that level. As an example, the last charge before trading in was 26.6 amperes at 243.3 volts. My 2019 draws a little more current than the 2015: 27.6 amperes at 244.2 volts, 27.0 amperes at 246.1 volts, 26.8 amperes at 250.1 volts, or 28.6 amperes at 236.3 volts. The 2019 will draw a little over 30 amperes when charging from a 208V nominal circuit if the EVSE pilot signal will allow. My Clipper Creek EVSE at my workshop garage allows 40 amperes and I saw 30.4 amperes at 214.3 volts the first time I charged there.
Based on the conversations above and the fact that the Nissan charger didn't fail on a 30amp breaker, does anyone know whether the Nissan charger has built-in intelligence that allows it to charge at a lesser rate? I'm thinking it may since the breaker didn't trip. I know it charges faster than the SplitVolt charger.

wwhitney
Posts: 779
Joined: Sat Jul 17, 2010 10:10 am
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Location: Berkeley, CA

Re: Installing 4-prong charger on 3-wire 240V distribution

Sun Dec 27, 2020 8:20 am

l6sman wrote:
Sun Dec 27, 2020 7:42 am
Based on the conversations above and the fact that the Nissan charger didn't fail on a 30amp breaker, does anyone know whether the Nissan charger has built-in intelligence that allows it to charge at a lesser rate? I'm thinking it may since the breaker didn't trip.
No.

A properly functioning 30 amp breaker may trip at 27 amps continuous after an hour. Or it may never trip at 35 amps continuous. The variation depends on manufacturing tolerances and the ambient temperature of the breaker (which in turn depends on how other breakers in the enclosure are loaded).

This variation in breaker trip characteristics is the reason for the 80% continuous load limit in the NEC.

Cheers, Wayne

l6sman
Posts: 8
Joined: Fri Dec 04, 2020 4:35 pm
Delivery Date: 04 Dec 2020

Re: Installing 4-prong charger on 3-wire 240V distribution

Sun Dec 27, 2020 9:03 am

wwhitney wrote:
Sun Dec 27, 2020 8:20 am
l6sman wrote:
Sun Dec 27, 2020 7:42 am
Based on the conversations above and the fact that the Nissan charger didn't fail on a 30amp breaker, does anyone know whether the Nissan charger has built-in intelligence that allows it to charge at a lesser rate? I'm thinking it may since the breaker didn't trip.
No.

A properly functioning 30 amp breaker may trip at 27 amps continuous after an hour. Or it may never trip at 35 amps continuous. The variation depends on manufacturing tolerances and the ambient temperature of the breaker (which in turn depends on how other breakers in the enclosure are loaded).

This variation in breaker trip characteristics is the reason for the 80% continuous load limit in the NEC.

Cheers, Wayne
OK thanks. Then does it hurt using the original Nissan charger since it seemed to work fine? There is no way to tell the Leaf to only charge at 24 amps instead of 30 amps is there?

LeftieBiker
Moderator
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Re: Installing 4-prong charger on 3-wire 240V distribution

Sun Dec 27, 2020 9:15 am

It doesn't "hurt" the charging cable, but there is a "risk" involved in using it this way, especially for more than a couple of hours. You will also be violating the National Electrical Code, and that may prevent an insurance payout if there is a fire.
Scarlet Ember 2018 Leaf SL W/ Pro Pilot
2009 Vectrix VX-1 W/18 Leaf modules, & 3 EZIP E-bicycles.
BAFX OBDII Dongle
PLEASE don't PM me with Leaf questions. Just post in the topic that seems most appropriate.

wwhitney
Posts: 779
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Location: Berkeley, CA

Re: Installing 4-prong charger on 3-wire 240V distribution

Sun Dec 27, 2020 9:45 am

l6sman wrote:
Sun Dec 27, 2020 9:03 am
OK thanks. Then does it hurt using the original Nissan charger since it seemed to work fine?
To my knowledge, the only hazard the NEC is seeking to avoid with the requirement of a maximum 80% continuous load on a breaker is the hazard of repeated nuisance tripping. This is a real hazard, as if the user gets in the habit of just resetting the breaker, then the breaker will wear, and the user will not be able to tell if it starts tripping for some other reason.

Also, I believe you mentioned that your garage is fed by a 30A 120V/240V circuit, and that it has other loads. Even if your breaker holds with the continuous 27.5A load of the Nissan Leaf alone, there is a significant probability of it tripping when other loads happen to come on. I.e. just because you tried the garage door opener once doesn't mean that there isn't a 1% or 5% chance of it tripping each time you use the garage door opener. Sticking with the 24A continuous EVSE would give you more headroom.

Lastly, I don't know what pilot signal the Nissan EVSE uses. If it advertises 30A or 32A, and you ever plug in another EV that can charge at that rate, you're quite likely to trip the 30A breaker.

So for those reasons, it is more prudent to use the 24A continuous EVSE, rather than the Nissan EVSE.

Cheers, Wayne

PS For those less familiar with the NEC, the requirement for continuous loads is written in terms of providing conductors with an ampacity (amp capacity) of 125% of the continuous load. Which at first glance suggests that the conductors themselves are in need of upsizing for continuous load. But basically every instance of this requirement has an exception stating that if the circuit is supplied by a "100% rated" breaker, then the conductors may be sized at 100% of the continuous load. A "100% rated" breaker consists of a single breaker in its own enclosure (to avoid heat buildup from other breakers) that has been tested to hold at a continuous current matching its rating. [And they basically don't exist smaller than 100A.] This shows that the continuous load requirements are due to the limitations of standard breakers, and nothing else.

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