Nissan's Included L1 (120v) EVSE

[surfingslovak]

The battery is made up of 192 Li-Ion cells, packaged in 48 modules. Each module contains four cells connected in series-parallel. That is, two cells in parallel, and then the two sets of parallel cells connected in series. The industry standard for full charge of a Li-Ion cell is 4.2 volts, so the resulting module voltage is 8.4 volts if fully charged.

48 X 8.4 volts = 403.2 volts.

I just came to the same conclusion yesterday night. I watched couple QC videos and the CHAdeMO charging station display was conveniently showing battery pack voltage and SOC percentage. It became evident that individual cell voltage was around 4.1V at about 80% SOC. It's virtually certain Nissan lets the battery cells saturate and reach 4.2V when charging the battery to "full". To be honest, I found this to be both surprising and sobering. I was hoping that they would internally limit cell voltage to 4.1 or 4.15V.

 

[Herm]

I just came to the same conclusion yesterday night. I watched couple QC videos and the CHAdeMO charging station display was conveniently showing battery pack voltage and SOC percentage. It became evident that individual cell voltage was around 4.1V at about 80% SOC. It's virtually certain Nissan lets the battery cells saturate and reach 4.2V when charging the battery to "full". To be honest, I found this to be both surprising and sobering. I was hoping that they would internally limit cell voltage to 4.1 or 4.15V.

So that settles that, now we know when Nissan says 100% they do mean 100%.. I was hoping that someone would measure pack voltage when the car was fully charged but apparently no one has.

They do recommend you only charge to 80%, so the long term life of the battery is still under your control. There is a report that total pack capacity is 27kwh, so perhaps they use that extra 3kwh as the permanent safety buffer on the low end.

Assuming the Chademo charger was charging a Leaf and that the display is accurate.

 

[surfingslovak]

Assuming the Chademo charger was charging a Leaf and that the display is accurate.

I rewatched the video and in the cold hard light of the day, I'm a little less sure about my conclusions. The CHAdeMO charger shows the charging voltage, not the battery pack voltage, but I would expect them to be nearly identical. I took four screenshots: at 62%, 72%, 79% and 83% SOC and the charging voltage is nearly constant 393V. PDXLeafer did not go all the way to 100%, which makes this even more of a guessing game.

 

[GaslessInSeattle]

I've come to the conclusion that either we are given acess to 100% of actual or close enough that 80% charging is preferable if driving needs allow and the referenced reasoning on total volts helped sway me. Also it's hard to imagine that Nissan has gone to all the trouble of a fairly nuanced limiting of regen between 100% & 80% if it wasn't important. I also feel that they would not have risked the PR challenge of suggesting 80% if it wasn't important. So many things line up, including the quick charging limit of 80%, that by default I plug in and charge to 80% whenever possible and use car wings for the occasional top off to 100%. It turns out it's of little consequence to me though, my average charging/driving interval has been well within the 80% limit. I would never have guessed that I drive such short distances on average. For me this has been as much an exercise in learning the difference between my perceived vs actual driving needs as anything else.
G

I just came to the same conclusion yesterday night. I watched couple QC videos and the CHAdeMO charging station display was conveniently showing battery pack voltage and SOC percentage. It became evident that individual cell voltage was around 4.1V at about 80% SOC. It's virtually certain Nissan lets the battery cells saturate and reach 4.2V when charging the battery to "full". To be honest, I found this to be both surprising and sobering. I was hoping that they would internally limit cell voltage to 4.1 or 4.15V.

So that settles that, now we know when Nissan says 100% they do mean 100%.. I was hoping that someone would measure pack voltage when the car was fully charged but apparently no one has.

They do recommend you only charge to 80%, so the long term life of the battery is still under your control. There is a report that total pack capacity is 27kwh, so perhaps they use that extra 3kwh as the permanent safety buffer on the low end.

Assuming the Chademo charger was charging a Leaf and that the display is accurate.

 

[garygid]

The battery voltage while charging is noticably higher than
the "resting" cell voltage. Remember that the QC might have MANY
amps going into the battery. The QC voltage of 393v (4.09 per cell)
during charging is NOT an indication that the cells are being
over-charged, or even charged to "too-full".

 

[tps]

For me this has been as much an exercise in learning the difference between my perceived vs actual driving needs as anything else.

Amen.

 

[surfingslovak]

The battery voltage while charging is noticably higher than
the "resting" cell voltage. Remember that the QC might have MANY
amps going into the battery. The QC voltage of 393v (4.09 per cell)
during charging is NOT an indication that the cells are being
over-charged, or even charged to "too-full".

Yes, of course, I'm with you. I don't know the internal battery impedance or the resistance of the wires, but I figured that the difference wouldn't be huge, especially when divided by 96.

What I was looking for was an indication of where the cell voltage of a charged battery might lie. If it's below 4V, slightly above or close to 4.2V. I would like to have accurate numbers, but this is closest approximation I have seen so far. One of the interesting aspects of PDXLeafer's video is that his charging voltage is pretty much constant at 393V all the way from 60% to 80%. I'd say that that's a good thing. We can also probably assume that the resting battery voltage at 80% is below 393V, and individual cell voltage is below 4.1V. If this holds up, that would be a good thing as well.

 

[Herm]

The charging voltage will be very close to the resting voltage of the pack (millivolts), because the impedance of the pack and cabling is low.. otherwise things would start to get hot real quick.

 

[garygid]

Charging at 100 amps, the Cell Voltage is likely to be
noticably elevated, and change as the cell charges.

Perhaps the 393 volts is a Maximum voltage limit, not
the actual charging voltage.

I assume that the LEAF asks the QC for a certain current,
and possibly sets a maximum voltage. Then, the charger
will lower/set the voltage as necessary during the charging
so as to not deliver more than the requested current.

 

[ebill3]

Well, my 2 pennies is that it is a constant current/constant voltage charge. The charge is in the constant voltage phase (4.1 volts/cell) and the current is decreasing as the voltage is held.

Had the charge continued, I would expect to see the pack at a final voltage of 393 - right at 80%.

Bill

 

[EVDRIVER]

This is the Nissan L1 EVSE thread.

 

[gmuzhik]

I just tried the L1 EVSE that came with my leaf for the first time this weekend and I had a couple questions:

1. Does anyone know what is inside the box? It says 120VAC 12 Amp input and 120VAC 12A output. Output = Input! I used it for three hours and it got quite warm. Anyone notice this? Obviously something is disappating the heat. I wonder what gives! It can't be the two lights.

2. The pigtail to the plug is so short that the box doesn't reach the floor (in the modern garage that I plugged it into) and it puts strain on the plug. It is pretty heavy and I am uncomfortable with the strain. Has anyone noticed this? I am thinking of bringing a little box or stand of some kind to rest the box onto.

Thanks,
GaryD

 

[DaveinOlyWA]

2. The pigtail to the plug is so short that the box doesn't reach the floor (in the modern garage that I plugged it into) and it puts strain on the plug. It is pretty heavy and I am uncomfortable with the strain. Has anyone noticed this? I am thinking of bringing a little box or stand of some kind to rest the box onto.

Thanks,
GaryD

see the two little eyelets on the box? bungee cord it and hang it next to the plug. that is what i did for a while. then i set up a stand to hold the thing

 

[smkettner]

2. The pigtail to the plug is so short that the box doesn't reach the floor (in the modern garage that I plugged it into) and it puts strain on the plug. It is pretty heavy and I am uncomfortable with the strain. Has anyone noticed this? I am thinking of bringing a little box or stand of some kind to rest the box onto.

Thanks,
GaryD

I use an appliance extension cord full time. 90* plug goes into the wall and drops straight down. Brick sits under the workbench. It is a ~5' cord #14 wire from Home Depot.

I have also used a 50' extension cord (#12 wire) for extended periods with no issues.

 

[surfingslovak]

The charging voltage will be very close to the resting voltage of the pack (millivolts), because the impedance of the pack and cabling is low.. otherwise things would start to get hot real quick.

I don't want to continue off topic on this L1 thread, but I talked to someone else earlier today and they indicated that L3 charging created quite a bit of heat. If you assume that the thermal heat power can be as high as 500W and is mostly dissipated by the battery, then a back-of-an-envelope calculation suggests a difference of 10V between charging voltage and resting battery voltage (@ 50A current). This translates to 0.1V on individual cell level. Given the readings from the CHAdeMO display, the implied resting cell voltage could be closer to 4V than to 4.1V.

And to get back to the actual topic, I did notice that the trickle charger gets quite warm, which is a mystery to me too. Based on what I've heard here and elsewhere, it's basically a safety device. I thought that they were using TRIACs in there. I played with them in the past and I although I used a heat sink then, I don't think that they were that lossy.

 

[charlie1300]

I just tried the L1 EVSE that came with my leaf for the first time this weekend and I had a couple questions:

1. Does anyone know what is inside the box? It says 120VAC 12 Amp input and 120VAC 12A output. Output = Input! I used it for three hours and it got quite warm. Anyone notice this? Obviously something is disappating the heat. I wonder what gives! It can't be the two lights.


Thanks,
GaryD

What's inside the box? See for yourself!

http://www.mynissanleaf.com/viewtopic.php?f=26&t=2633


Remember that the L1 EVSE has to have all the J1772 standard functionality that a L2 EVSE has, Just at 120V/12 Amp instead of 240V/16/24/32 amp. Link to some info on J1772 and upgrade of L1 to L2.

http://www.mynissanleaf.com/viewtopic.php?f=4&t=3625

 

[tps]

Obviously something is disappating the heat.

Phil did an infrared image of his modified EVSE after a 26A torture test, and he came to the conclusion that much of the heat during normal operation was being dissipated by the relay coils.

http://www.mynissanleaf.com/viewtopic.php?f=26&t=3981

 

[omkar]

I did a quick search and didn't find this already mentioned...

It took a few tries but I managed to find a lock for the J1772 connector on the Nissan L1 EVSE:
Master Lock 131T

The 5mm shackle diameter fits just right.

 

[jacobp]

This EVSE is for 120v use ONLY (NOT 240v), and is intended for the USA marketplace.

It has a "max-current" setting of 12 amps, intended to work well on an otherwise-unloaded 15-amp circuit. It may also be used on a 120v 20-amp circuit.

To allow the very limited 1.44 kW (120v times 12 amps = 1440 watts) usage, it asks the attached car to not draw more than (approximately) 12 amps.

It draws about 0.03 amps (4 watts) when just plugged into the wall, but not connected to the car.

Apparently it is about 25 feet in total length, with its small, 3-indicator, no-controls EVSE "box" within about 12" of the wall-plug end.

Being small and light weight, it (with the coiled cord and two connectors) fits into a small "storage pack", for easier "clean" transportation.

I would recommend including a cleaning rag in the "bag", to wipe dirt and grime off the cord after it is used.

Modification possibilities:
Illegal, and currently unknown.

Possible Variations:
1. Allow the car to draw 16 amps, only for use on a 20-amp circuit (which are fairly common in garages). The charger in the LEAF can use the extra 4 amps of current.
2. Limit "max-current" to 8 amps to use the EVSE on older 10-amp circuits.
3. Design a 120/240v version that could work "almost anywhere" (my favorite).
See the thread on the now-available "Mod for L1 AND L2 Usage", for about $198. Very nice, and reported to draw only 1 watt when idle.

Can someone confirm the actual length of this cable. I am installing a dedicated line this week and I need to know how long this cable is. Thanks.

 

[GeekEV]

I've had mine modified already so I can't check the original length, but it's about 6 inches. Just install your outlets at normal height and get a short extension cord (with appropriate amp rating).