100 kW Charging

[cwerdna]

That calculates to 20 kW/hour (31 kW in 1.5 hours). Then there is time remaining 4 hours. Lastly, what does the 99 indicate? I understand it's supposed to be the rate, but that does not make sense.

You keep making unit mistakes. Charging rate is measured in kW, a unit of power. There's no /h, no /hour, no per hour.

For "31 kW in 1.5 hour", are you talking about 31 kWh? Energy is measured in kWh.

If you charge at 50 kW * 1 hour --> 50 kWh came out of the "wall". Multiply units and values.
50 kW * 2 hours --> 100 kWh

100 kWh / 2h --> 50 kW as h divided by h cancels out.

31 kWh / 1.5 hours --> ~20.67 kW

20.67 kW * 1.5 hours --> 31.005 kWh

Notice the chargers are labeled in kW. When you charge, watch the screens. You'll see that the power level is correctly in kW and energy dispensed is correctly in kWh.

Skip to 7:00 of the video at https://insideevs.com/news/495913/nissan-leaf-dc-fast-charging-curve/. Notice that charging power is in the middle (kW). Energy dispensed is in kWh (upper right).

Watch the video at https://electricrevs.com/2018/07/17...hargepoint-express-250-charge-at-up-to-55-kw/. The software on that unit gives a bit more info. Yes, I know it's a Bolt.

 

[BillAinCT]

Is everyone reading the max shown on page CH-8 of the manual (Max 66 kW/hour)?

I was reading the EVgo display that says 72kW active power. Do I need to post this?

 

[BillAinCT]

I'm not sure what adding 2 temp bars means since the temp indicator in the 2022 lead has no bars and no values.

What are you talking about? It has 12 bars. 2 blue, 8 white, and 2 red. I know ballpark temp where I'm at and the adding 2 bars was just a statement. I should have said at the previous 43kW charging sessions it usually added 1 bar but maybe once or twice it added 2 bars. 5 bars displayed is ideal around 65-75F. I approximate 15-20F per bar. I've asked on here for a table of bar to degrees. It's also a big bitch of mine that they can't give us the digital display!

 

[Ndp1234]

I have not tried any of the stations listed in this thread but I absolutely hate EVGO chargers. They are really slow and unreliable in my experience. For the 50 kWh chargers I usually only get between 28-38. For their 100 kWh I usually get around 50 kWh. However, I have had speeds in the 70s at other branded “superchargers” that are marked 100 kWh, mainly the ones that are sponsored by NYS Evolve NY. The speed usually goes down a little every 10% or so but I’m still netting way better than if I were at the 50 kWh EVGo.

 

[Yodrak]

The numbers speak for themselves. The best rate shown on page CH-8 is 66 kW/hour. That is calculated from 80% of 62 kWh (49.6 kWh) in 45 minutes (0.75 hours).
...

ram, please, the rate is 66 kW, NOT kW/h. kW/h is meaningless, kW is itself the rate. In your example of 49.6 kWh / 0.75 h the 'h' cancels out leaving only kW.

(Apologies, I belatedly see that cwerdna has already tried to correct the misunderstanding.)

 

[ramisalah]

ram, please, the rate is 66 kW, NOT kW/h. kW/h is meaningless, kW is itself the rate. In your example of 49.6 kWh / 0.75 h the 'h' cancels out leaving only kW.

(Apologies, I belatedly see that cwerdna has already tried to correct the misunderstanding.)

As can be seen in the attached picture, the term "charging speed" is used. Just like you cannot have a speed of an object without time in the denominator (per hour), the charging speed at a charger is how many kilowatts are being added per unit time. So, if I am charging at a charger that display 48 kW, this indicates that I will add 12 kW in 15 minutes on average. Or if I drove up to this charger with 10 kWh left in my battery and waited 15 minutes, I would expect to be at 22 kWh. Whenever there is flow of energy being added, flow has a rate. Just like you cannot fill a bathtub without having a flow rate (such as gallons per minutes), you cannot fill a battery without flowing energy at a rate per a time basis. Please read the article at the link below on the use of kW rating for a charger to indicate kW/hour. It is a convention since it is implied that flowing energy is a rate over time.

The bottom line is that 100 kW charging rate is not achievable under any real life circumstances.
Erroneous arguments about units does not change that fact.

https://bppulsefleet.com/blog/kw-vs... EV world, kilowatts,faster you can charge up.

 

[ramisalah]

What are you talking about? It has 12 bars. 2 blue, 8 white, and 2 red. I know ballpark temp where I'm at and the adding 2 bars was just a statement. I should have said at the previous 43kW charging sessions it usually added 1 bar but maybe once or twice it added 2 bars. 5 bars displayed is ideal around 65-75F. I approximate 15-20F per bar. I've asked on here for a table of bar to degrees. It's also a big bitch of mine that they can't give us the digital display!

I agree with you that we should know the temperature. Not sure if you could see the "thermostat" in the attached picture. I don't see the bars you're referring to. I see the two blue check marks and two amber check marks at the left and right of the thermometer.

This is the other issue with the Leaf. It is one of the few EV's with no battery cooling which leads the battery temperature to go up once it starts charging making the most optimum charging rate to be very elusive.

So many Leaf battery charging issues!!

 

[cwerdna]

I have not tried any of the stations listed in this thread but I absolutely hate EVGO chargers. They are really slow and unreliable in my experience. For the 50 kWh chargers I usually only get between 28-38. For their 100 kWh I usually get around 50 kWh. However, I have had speeds in the 70s at other branded “superchargers” that are marked 100 kWh, mainly the ones that are sponsored by NYS Evolve NY. The speed usually goes down a little every 10% or so but I’m still netting way better than if I were at the 50 kWh EVGo.

There are not 50 or 100 "kWh" chargers. Charging speed is rated in kW, a unit of power.

Look again at EVgo's app. Look again at the charger's markings and displays while charging. Look at the displays in the car.

 

[BillAinCT]

This is the best I can do to show the bars.

If the Leaf makes you so unhappy, did you not do your homework before purchase?

 

[cwerdna]

As can be seen in the attached picture, the term "charging speed" is used. Just like you cannot have a speed of an object without time in the denominator (per hour),

Wrong. Watts already have a time in the denominator. A watt is a joule per second.

So, 1000 joules per second per hour doesn't make any sense when you're talking about charging speed. kW per hour or kW/h could make sense if lets say you had a megawatt power plant and you're talking about the rate at which it can ramp up to 1 megawatt output.

the charging speed at a charger is how many kilowatts are being added per unit time.

No idea what this means. Watts and kilowatts are instantaneous power. Can be a second, an hour, 1000 hours, etc.

You can talk about how many kilowatt-hours (- is a dash, not a minus) are added over time. This is why kWh / h (kilowatt-hours per hour) is what kW is. kWh / h --> kW since h/h cancels out.

If you wish, you can keep writing kWh/h. It's correct but it's extra typing since it becomes just kW.

If you have a 1 watt device that runs for 1000 hours --> 1 watt * 1000 hours --> 1000 watt-hours --> 1 kWh
1000 watts * 1 hour --> 1000 watt-hours --> 1 kWh

6 kW * 1 hour --> 6 kWh
6 kW * 2 hours --> 12 kWh

6 kWh / 1h -> 6 kW
12 kWh / 2h --> 6 kW

So, if I am charging at a charger that display 48 kW, this indicates that I will add 12 kW in 15 minutes on average.

48 kW is the charging speed. kW is a unit of power.

Nope on the latter.

48 kW * 0.25 hours = 12 kWh. Multiply units and values.
12 kWh / 0.25 hours = 48 kW. Again, notice h/h cancels out.

Please read the article at the link below on the use of kW rating for a charger to indicate kW/hour. It is a convention since it is implied that flowing energy is a rate over time.

Wrong.

https://bppulsefleet.com/blog/kw-vs-kwh-what-it-means-for-your-ev/#:~:text=In the EV world, kilowatts,faster you can charge up.

Skimmed article. Saw no reference to using your incorrect units of "kW/hour". Nowhere on that pic you attached does it say anything like kW/hour, kW/h nor kW per hour. Re-read it again. Also look at https://www.power-sonic.com/blog/kw-vs-kwh-explained/, for example.

You'll notice again, charging rate in kW and energy dispensed (which always counts up until charging stops), in kWh.

 

[cwerdna]

We've had to educate people on this before many times.

Example was nerys at https://mynissanleaf.com/threads/some-questions-what-charger-what-are-these-holes.17985/#post-389319. https://mynissanleaf.com/threads/so...what-are-these-holes.17985/page-3#post-389442 is correct.

If you skip to ~8:48 of https://insideevs.com/news/495913/nissan-leaf-dc-fast-charging-curve/, you'll see that in 30 minutes, 31 kWh of energy was delivered.

31 kWh / 0.5 hours = 62 kWh/h --> 62 kW
This makes sense vs. what I could make out. He started at high 60s kW and got to as high as 69 kW and then it started ramping down. Looks like it was at ~55 kW at the 30 minute mark.

 

[knightmb]

What's special about this one EVgo location?
This picture has so much confusing info. It shows 1.5 hours to 100% from about 50%. That calculates to 20 kW/hour (31 kW in 1.5 hours). Then there is time remaining 4 hours. Lastly, what does the 99 indicate? I understand it's supposed to be the rate, but that does not make sense.

I can give context, this is my Leaf. This picture was taken at a 500V ChaDeMo station. The first issue is the time estimates are wrong because the Leaf does not show charge times less than 5 minutes, even if only 1 second remains before the next "mark" is reached. Long standing bug in the Leaf charge calculator. That's why it shows 1.5 Hours for 100% (which would also not be true as even a low power ChaDeMo would not take that long) and why when I posted the picture, I made note that the charge times are all wrong, but the power level is correct.

Near the bottom of this page is where you will find that info:
https://mynissanleaf.com/threads/qc-charging-study-nissan-vs-ea-vs-evgo-vs-chargepoint.33644/page-2

 

[knightmb]

The numbers and the feedback are in agreement. The Nissan Leaf is unable to charge at anywhere near 100 kW in any real world situation.

Experience trumps logic on this one. It is possible, I have proof. What you are getting incorrect is that it can't keep this level of power for very long because as the battery heats up and the SOC climbs, it will have to taper down at some point. So on the technical point, the Leaf CAN NOT sustain 100 kW for very long, like maybe 5 or 6 minutes before the taper down will decrease the power over time. But to say "never ever possible", you would be incorrect and the math is there to prove it's possible, even in your own linked documents you are showing us.

 

[DavidBurbidge]

First comment. It’s nice to see picky, detailed disagreements discussed in a positive and polite way. Participants in many Discussion forums get nasty very quickly, for no reason other than what appears to be personal angst. Way to go, y’all. Second comment. I am technologically naïve. See third comment for reference. Third comment. Could you turn on your air conditioner while charging to keep the battery cooler?

 

[css28]

First comment. It’s nice to see picky, detailed disagreements discussed in a positive and polite way. Participants in many Discussion forums get nasty very quickly, for no reason other than what appears to be personal angst. Way to go, y’all. Second comment. I am technologically naïve. See third comment for reference. Third comment. Could you turn on your air conditioner while charging to keep the battery cooler?

The air conditioner has no way to cool the battery pack. The battery cells are sealed in a big metal can underneath the car.
As far as I know, the LEAF is the only currently marketed EV that does not have active battery temperature management. That is its Achilles Heel.

 

[ramisalah]

There are not 50 or 100 "kWh" chargers. Charging speed is rated in kW, a unit of power.

Look again at EVgo's app. Look again at the charger's markings and displays while charging. Look at the displays in the car.

When kilowatts of power are added to the battery over a period of time, that is adding kW's per time, kW/hour. Once in the car, the value is referred to as kWh (62 kWh in the case of the Leaf) meaning that the storage medium (the battery) is able to dispense that many kilowatts in that amount of time. So, if I draw 1 kW from a battery that includes 62 kWh, the battery will be depleted in 62 hours.
The units are not the issue here. Arguing about units is a red herring.
I see that some are intent on arguing about units. A Watt is Joules/second. A Joule is equal to Kg.m2/s2. We could go on an on with units, red herring.
The main point stands that the Nissan's Leaf's claim of charging at 100 kW per hour is not achievable. I can see minor offsets. But no one can achieve a rate anywhere near 100 and that's due to the design of the car, its battery (no cooling) and the charging system. Charging rates in the 60's are barely achievable and most drivers get less than 50 making the mention of the 100 to be just a marketing scheme. Graphs were shared of the maximum EVgo (Nissan's partner) charging rate. We all also know that the Leaf's battery has an Achilles heal without cooling. So, once plugged in, it heats up and gets a rate below 50. That's probably an unpleasant surprise to most Leaf drivers.

 

[ramisalah]

First comment. It’s nice to see picky, detailed disagreements discussed in a positive and polite way. Participants in many Discussion forums get nasty very quickly, for no reason other than what appears to be personal angst. Way to go, y’all. Second comment. I am technologically naïve. See third comment for reference. Third comment. Could you turn on your air conditioner while charging to keep the battery cooler

An air conditioner pushes cool area in a chamber by taking the heat away to a evaporator. If you stand outside by the AC at the window, you will feel all that heat. So, the AC will not cool the battery or its compartment, it may even create more heat.

 

[BillAinCT]

So, the question is: why does Nissan go to lengths to advertise the 100 kW chargers with EVgo and give the impression that the Leaf can charge at 100 kW/hour rate (or a value reasonably close to 100)?

Because EVgo has 50kW and 100kW chargers. In my experience using a 50kW EVgo I never saw more than 44kW. Using a 100kW EVgo, I saw 73kW every time starting. They are differentiating the 2 EVgo choices. This doesn't make the statement or even imply that the Leaf is capable of charging at 100kW.

 

[BillAinCT]

The main point stands that the Nissan's Leaf's claim of charging at 100 kW per hour is not achievable.

Please post a Nissan statement where they claim that the Leaf is able to charge at 100kW. Because they direct you to 100kW EVgo chargers doesn't even imply that but if you want to read it that way that's you making the claim, not them.

 

[ramisalah]

Because EVgo has 50kW and 100kW chargers. In my experience using a 50kW EVgo I never saw more than 44kW. Using a 100kW EVgo, I saw 73kW every time starting. They are differentiating the 2 EVgo choices. This doesn't make the statement or even imply that the Leaf is capable of charging at 100kW.

Is this an official Nissan response?