30 Kwh Leaf showing up on Nissan.ie

cros13 · 12-10-2015 12:45pm

BoatMad wrote: »

commanded via the can bus from the leaf

Usually this. the car is supposed to know it's battery capacity, condition, temperatures etc and determine the charge profile. They are having enough trouble these days pushing out basic compatibility updates to rapids because there are still issues with certain manufacturers implementations of the rapid charging standards.

My i3 rapid charges much more aggressively than the Leaf, maintaining 380V 110A to about 45% SoC before beginning to drop, in any weather above 10 degrees the compressor has usually kicked in before 40% and the pack is being cooled while charging. Then at around 70% SoC it tapers off much more aggressively than the Leaf, so it's really not worth the time waiting around after 80%. It's still fairly conservative, I've used a similar cell in the same form factor and NCA chemistry from Samsung SDI for other projects. Samsung says they'll do 5C charging or 7C for up to 30 seconds. That's bollocks TBH... they're happiest at 2C, great anywhere in the 1-3C range and OK fo very short bursts to 4C.

BMW has talked about the car supporting 100kW rapids so I don't know how it would behave if more power was available from the rapid.

BoatMad · 12-10-2015 4:10pm

cros13 wrote: »

Usually this. the car is supposed to know it's battery capacity, condition, temperatures etc and determine the charge profile. They are having enough trouble these days pushing out basic compatibility updates to rapids because there are still issues with certain manufacturers implementations of the rapid charging standards.

My i3 rapid charges much more aggressively than the Leaf, maintaining 380V 110A to about 45% SoC before beginning to drop, in any weather above 10 degrees the compressor has usually kicked in before 40% and the pack is being cooled while charging. Then at around 70% SoC it tapers off much more aggressively than the Leaf, so it's really not worth the time waiting around after 80%. It's still fairly conservative, I've used a similar cell in the same form factor and NCA chemistry from Samsung SDI for other projects. Samsung says they'll do 5C charging or 7C for up to 30 seconds. That's bollocks TBH... they're happiest at 2C, great anywhere in the 1-3C range and OK fo very short bursts to 4C.

BMW has talked about the car supporting 100kW rapids so I don't know how it would behave if more power was available from the rapid.

I agree, and you know your stuff. high C charging is fraught with issues and most EVS Id suggest are probably <2C. Im suprised the Leaf seems soooo conservative , tapering from about 60-65% is unusual . I designed chargers for high Kwh , marine Li applications and we could push the taper point to 75% with little issue

Soarer · 12-10-2015 9:22pm

Jaysus lads.

BoatMad · 12-10-2015 11:32pm

Soarer wrote: »

Jaysus lads.

You need to know advanced lithium charging science to drive a leaf , you mean you didn't know that

samih · 13-10-2015 10:17am

Leaf doesn't have thermal management so the battery will begin to overheat with successive rapid charges even with the current charging profile.

I saw 9 bars of temperature during one of my drives after the 4th rapid charge of the day. So don't plan on driving over 600 km a day would be my advice.

BoatMad · 13-10-2015 10:29am

samih wrote: »

Leaf doesn't have thermal management so the battery will begin to overheat with successive rapid charges even with the current charging profile.

I saw 9 bars of temperature during one of my drives after the 4th rapid charge of the day. So don't plan on driving over 600 km a day would be my advice.

Thats a strange you would assume that a steady state temp be achieved in-between fast charges, it not like the battery doesnt cool

cros13 · 13-10-2015 11:33am

BoatMad wrote: »

Thats a strange you would assume that a steady state temp be achieved in-between fast charges, it not like the battery doesnt cool

It's prismatic cells stacked on top of one another, heat rises up through the pack and there's a lot of thermal mass in the pack to cool.
The temperature reading is from next to the cells worst impacted by this and slowest to cool, because they are insulated and heated by other cells in the horizontal and vertical, and of course the cabin itself further insulates the pack.

13-10-2015 12:22pm

The cells are not nearly as heat sensitive for the 2014+ batteries, but you still don't want to get it too hot for long by fast charging it to death.

I think they may have increased cycle life and also made it less sensitive to heat it only takes small changes to greatly increase life.

BoatMad · 14-10-2015 12:29am

Deleted User wrote: »

I think they may have increased cycle life and also made it less sensitive to heat it only takes small changes to greatly increase life.

Within the current NMC Li variant, it is possible to dope the cathode to try and min max the characteristics so there a little room for improvement in reality.

I suspect the 30 kW battery is a result of improved packaging density soley. I suspect the FCP charging will be at conservative as ever , but the initial CC phase will be increase to 50 kW. Little heating occurs in this region anyways ( compared to elsewhere.

14-10-2015 2:01am

You can't pull 50 Kw form the chargers. They're 45 Kw.

Fast charging is conservative because the cells have no thermal management.

There is a limit how useful higher rates of charging are on small batteries and why 100 Kw charging on the Kia soul makes no real life difference.

100 Kw + will be a lot more useful on large batteries.

100 Kw will just get the battery to the point where the power starts to ramp down much faster in a small battery.

Nissan quotes 30 mins for the Leaf 30 kwh V and Kia quotes 25 mins for the Soul EV at 100 Kw.

When you get you leaf and leaf spy time and time again you won't see any difference, it will pull 45 Kw form the charger at the right temperature and charge % and at that same point it will start to ramp down lower and lower as the charge % rises. The more power you dump into that battery the faster the ramp down will happen.

With my electric bike projects it's the same process as is the same will all lithium batteries you can start at a higher charge rate but you will finish much lower.

BoatMad · 14-10-2015 2:09am

Deleted User wrote: »

You can't pull 50 Kw form the chargers. They're 45 Kw.

Fast charging is conservative because the cells have no thermal management.

There is a limit how useful higher rates of charging are on small batteries and why 100 Kw charging on the Kia soul makes no real life difference.

100 Kw + will be a lot more useful on large batteries.

100 Kw will just get the battery to the point where the power starts to ramp down much faster in a small battery.

Nissan quotes 30 mins for the Leaf 30 kwh V and Kia quotes 25 mins for the Soul EV at 100 Kw.

When you get you leaf and leaf spy time and time again you won't see any difference, it will pull 45 Kw form the charger at the right temperature and charge % and at that same point it will start to ramp down lower and lower as the charge % rises. The more power you dump into that battery the faster the ramp down will happen.

With my electric bike projects it's the same process as is the same will all lithium batteries you can start at a higher charge rate but you will finish much lower.

Fine 45 50 whatever , I see many of the fcps rated at 50 kW.

As to how a Li is charged I'm not going over this again , you mix up charge strategies with Li characteristics.

Larger batteries require greater power to be charged in the same time. This is a fact of physics

Taper strategies are just that, a strategy , the manufacturer of the battery will set max rate of charge , CC CV transition point and rate of taper to suit the application at hand bearing in mind thermal handling , cycle life, charger accuracy , etc lithiums are utterly promiscuous with regard to charging unless controlled.

For example , if you want to maximise charge time, you can high C charge very close to the upper " knee" , you can in effect sacrifice the saturation taper charge. In the process you compromise cycle life , this is what RC modellers do.

For example in my designs, where I want very long life . I charge at 0.5 C to 65 % with no taper. The charger just stops.

There is a limit how useful higher rates of charging are on small batteries and why 100 Kw charging on the Kia soul makes no real life difference.

You can charge Li at 20C if you know what you are doing and are prepared to compromise cycle life ,the Li battery will happily take it. ( ps don't try this at home folks )

There's a reason the RC boys have taken to huge C charging in metal boxes with sand in them

14-10-2015 2:11am

As the battery ages and internal resistance grows the battery will charge slower and slower from the fast charger as is observed by a member on the Irish EV association FB page which I'm sure Dexter can back up my claim. Because his battery is ageing he can only pull about 35 Kw from the fast charger. Compared to about 51 Kw for me until the ramp down phase. However, this is observed from the actual readout on the charge point which is the total consumption of the charger there will be less going to the battery. In reality about 44 Kw goes to the battery or roughly 110 amps until ramp down stage for my leaf.

As it ages it will heat faster the more you fast charge it and this accelerates degradation at this stage there will come a point when regen will not be as strong and will decrease over time.

For the 2014+ Leaf this shouldn't happen for a long time. But it will age also just not as fast.

14-10-2015 2:23am

BoatMad wrote: »

Fine 45 50 whatever , I see many of the fcps rated at 50 kW.

As to how a Li is charged I'm not going over this again , you mix up charge strategies with Li characteristics.

Larger batteries require greater power to be charged in the same time.

Taper strategies are just that, a strategy , the manufacturer of the battery will set max rate of charge , CC CV transition point and rate of taper to suit the application at hand bearing in mind thermal handling , cycle life, charger accuracy , etc lithiums are utterly promiscuous with regard to charging unless controlled.

Yes a very large battery will require more power to charge at the same time but the difference between 21 and 27 Kwh (usable) isn't much so the larger 27 Kwh battery doesn't hit the ramp down phase for longer than the 21 kwh so it's allowed if you like, to charge at a faster rate for longer but not much longer.

Again this is the main reason the Soul EV has just 5 mins advantage over the Leaf 30 Kwh and 24 Kwh @ 100 Kw.

BoatMad · 14-10-2015 2:31am

Deleted User wrote: »

As the battery ages and internal resistance grows the battery will charge slower and slower from the fast charger as is observed by a member on the Irish EV association FB page which I'm sure Dexter can back up my claim. Because his battery is ageing he can only pull about 35 Kw from the fast charger. Compared to about 51 Kw for me until the ramp down phase. However, this is observed from the actual readout on the charge point which is the total consumption of the charger there will be less going to the battery. In reality about 44 Kw goes to the battery or roughly 110 amps until ramp down stage for my leaf.

As it ages it will heat faster the more you fast charge it and this accelerates degradation at this stage there will come a point when regen will not be as strong and will decrease over time.

For the 2014+ Leaf this shouldn't happen for a long time. But it will age also just not as fast.

The issue here is the use of terms like " pull "

When designing a charge strategy , a charger design will limit the voltage rise in constant current mode to ensure a particular stress level on the battery is maintained. It's not a true infinite constant current source.

In that regard what's tends to happen as lithiums age is the transition voltage from CC to CV comes up quicker , because ageing in lithiums is really translated into lower capacity rather then lower acceptance. Typically because plating of the anode has occurred as well as other issues.

You keep assuming that nissan will allow the battery to pull whatever it wants , no company charges like that. Nissan will fix the charging strategy to ensure charging is carried out at a particular percentage of battery capacity.

So let's for argument say nissan has decided 1.5 C and 4.1 v transition , the charger will be commanded to only deliver that charge rate , and to switch to a defined taper at that defined voltage.

Any decent charge strategy must take into account battery ageing, so again , a smart charger or BMS , will count battery age and will adjust the charge parameters according. It has nothing to do with internal resistance , because the resistance on a Li , is so low , that you can easily charge at 10 C even with an old battery if you want.

Again it's not a characteristic of the battery that you are seeing , it's a defined charge strategy.

Li cycle life and capacity fall off , is the subject of current doctoral thesis, much of which is done by the Chinese. It's related to absolute cycles , short cycles , charge strategy , temperature , consumption strategies and simple passage of time. It's unlikely that nissan have improved the battery significantly, rather more optimised one of the things I mentioned.

BoatMad · 14-10-2015 2:49am

Deleted User wrote: »

Yes a very large battery will require more power to charge at the same time but the difference between 21 and 27 Kwh (usable) isn't much so the larger 27 Kwh battery doesn't hit the ramp down phase for longer than the 21 kwh so it's allowed if you like, to charge at a faster rate for longer but not much longer.

Again this is the main reason the Soul EV has just 5 mins advantage over the Leaf 30 Kwh and 24 Kwh @ 100 Kw.

????

A larger battery will require more power to charge in the same time in the CC portion of the charge cycle. This as I said to you before is a nearly linear portion of the charge curve. In this region charging power remains almost constant through out this phase.

Hence for that phase , to reach the same transition voltage , in the same tine requires proportionally more power to be drawn from the charger.

Assuming the transition voltage is the same the taper curve is actually very similar across battery capacities that are charged at the same C rate

Hence in the 30 kW battery , nissan will have the BMS system command a higher power for the CC phase , the CV phase being typically the same because the same C charge rate is used for both batteries.

If you increase the C charge rate. To get 100 % , you then find you have to increase the saturation charge phase , ie longer taper time. This partially negates the higher C rate in 100 % charging, but less so if you just are interested in tine to 60 or 70 %

Just to be clear , without control , in essence a Li battery will suck everything in . Putting a 100kw charger on a small battery without control would result in its destruction. This is the whole purpose of the particular CC phase. If you used a big lead acid charger , which are typically constant voltage , you'd fry a Li with uncontrolled charging currents

This is not the same for lead acid, as these have a given charge acceptance rate. Once that's reached, you cannot charge any faster , so using a bigger charger has no effect.

14-10-2015 2:53am

BoatMad wrote: »

It has nothing to do with internal resistance , because the resistance on a Li , is so low , that you can easily charge at 10 C even with an old battery if you want.

Again it's not a characteristic of the battery that you are seeing , it's a defined charge strategy.

You're joking right ? wow.

Charge the leaf battery at 10 C and see what happens to it's life , charge any battery not designed for 10C and see what happens.

Discharge any battery also not designed for this and see what effects it had.

Internal resistance has no effect ?

Read this form .

University of Wisconsin Milwaukee
UWM Digital Commons

http://dc.uwm.edu/cgi/viewcontent.cgi?article=1246&context=etd

We also know that with the rise in internal resistance, the battery performance deviates
and degrades. This results in a rise in the charging time and degraded performance of the
battery pack during the driving cycle.

The charge process from grid for all batteries in the group is shown as in Fig. 4.6. The
charging time increases as the internal resistance of the battery increase.

cros13 · 14-10-2015 4:24am

Deleted User wrote: »

You can't pull 50 Kw form the chargers. They're 45 Kw.

The different models have different ratings.

All the ChaDeMo only units in Ireland are 50kW as are all the DBT rapids. However the efacec QC45s (like the multi-standard at Naas) while it states in the spec sheet "up to 50kW", in the three connector configuration ESB have it only provides 45kW. The 50kW "peak" is only possible in configurations without the AC and can't be sustained even then.

14-10-2015 11:07am

5 Kw isn't going to make huge differences anyway.

cros13 · 14-10-2015 4:31pm

Deleted User wrote: »

5 Kw isn't going to make huge differences anyway.

Nope... just me being pedantic....

BoatMad · 15-10-2015 9:54am

Deleted User wrote: »

You're joking right ? wow.

Charge the leaf battery at 10 C and see what happens to it's life , charge any battery not designed for 10C and see what happens.

Discharge any battery also not designed for this and see what effects it had.

Internal resistance has no effect ?

Read this form .

University of Wisconsin Milwaukee
UWM Digital Commons

http://dc.uwm.edu/cgi/viewcontent.cgi?article=1246&context=etd

We also know that with the rise in internal resistance, the battery performance deviates
and degrades. This results in a rise in the charging time and degraded performance of the
battery pack during the driving cycle.

The charge process from grid for all batteries in the group is shown as in Fig. 4.6. The
charging time increases as the internal resistance of the battery increase.

Frankly I give up. Unless you tell me your qualifications , in this area, I will not continue a technical topic , as you continuously mis-understand the published data.

The paper you published , with is for a masters ( a little bit better then a degree student ) looks at replacement strategy as a function of age and usage

Tests were done on a approx 1kwh battery pack charged very conservatively , not at all like fast charging. Applying a standardised charging regime across three groups of batteries to show the effects of ageing on a charge cycle.

None of this is new stuff.

But we are talking about fast charging at > 1C. In that case internal resistance changes have little effect ( or lessor effect ). If a manufacturer doesn't change the CC phase as the battery ages, the charging regime puts increasing stress on the battery.

Let's break this down
Again I pointed out. The maximum power drawn from a charger during CC phase , is controlled by the charger /bms and not the battery

Question 1. Do you accept that ?

question 2. Do you understand and accept what CC charging is and that for large banks power remains roughly constant throughput the CC phase ?

I have stated my experience in this field , I am an EE for nearly 30 years with experience in battery charger design , portable battery operation , and I worked in designing robotised car assembly systems. I have direct experience with lead acid systems, Nicd , nimh, and Li ( LiCo , LiMn and Lifepo4 )

Question 3.

What is your qualification and experience in this field. .( this is of genuine interest to me as it lets me understand what technical detail I should pitch my explanations at )

Ps. It's entirely possible to charge at 10C or even greater , however you trade safety and battery life for incredibly fast recharge. It's rarely done on large banks because of safety and difficulty of charger design. But Li technology can be incredibly fast charged.

I never said nissan did this , I was pointing out , that you cannot just connect a Li battery to any size of charger without controlling charge , like you seem to think you can.

If you could answer the questions , we could step through the theory and practice piece by piece to see where your view diverges from mine

And please no more post grad " studies " that aren't relevant , or at least read them yourself

Thanks

BoatMad · 15-10-2015 10:02am

Deleted User wrote: »

5 Kw isn't going to make huge differences anyway.

It's 25% of the battery pack per hour and close to what's needed to ensure that the 30 kWh can be charged in the same time as the 24 ( it being approx 20 % bigger or 6 KWh )

As I understand it nissan set the max charge at 40 kW for the 24 kWh battery or about 1.7 C. But with a very conservative knee voltage ( at about 65 % SOC )

noelf · 22-10-2015 5:04am

Just read the first review on the new Nissan leaf 30kwh on www.honestjohn.co.uk just wondering what you all think about it ?

22-10-2015 6:52am

noelf wrote: »

Just read the first review on the new Nissan leaf 30kwh on www.honestjohn.co.uk just wondering what you all think about it ?

Quote

"Really, the Leaf’s biggest problem is that it’s actually a below average family hatchback in many ways. The plastics are hard and cheap, the design is dull, the steering wheel doesn’t adjust for reach, the seat is set too high, it’s actually not very quick from 30mph onwards, the boot is an awkward shape and - running costs aside - it’s expensive."

End Quote

The plastics are hard and cheap but I don't find the Leaf a bad place to sit compared to a boring mid spec Golf in all fairness.

The steering doesn't adjust for reach = true.

The design is dull compared to what , a VW ?

Seat set too high ? it is high but I think it's fine.

The boot is a bit awkward I agree but it's good enough for me and a big buggy.

Running costs aside it's expensive, yes it is expensive but the mid spec is probably still less expensive as a lesser equipped Golf mid spec with 2.0L TDI Automatic DSG.

The TDI would be faster at the top past 70 mph.

The leaf gets from 0-60 in 9.9 seconds and this has been independently tested several times.

Not fast past 30 mph ? BS it's quiet fast to 60 mph for a 104 HP car that weighs 1,493 Kg above 60 it's not as fast but it pulls well all the way to the limiter of 164 Kph. Where it does 94 mph in reality Nissan give the actual speed as the cut off which would be 164 Kph in all cars which must by law over read the speed by about 7 Kph. So while the leaf reaches 164 Kph by the clock this is the same speed most other cars would be at at this same reading.

Honest John isn't as honest as he likes people believe. Like everyone else he gives an opinion which like all other so called Auto reviewers they don't have to live with the car. He has the same bias towards the cars he doesn't like like everyone else.

My opinion to someone who is interested in a Leaf is to go and test drive it and make up their own minds.

Leaf is an average car and it's not meant to compete with premium brands.

It's higher equipped than a Golf or most other cars and costs a fraction of the money to run.

The fact Honest John could call the Leaf a below average car makes me realise how full of crap he really is. Perhaps he doesn't like electric cars ?

If someone wants better interior then they can check out the E-Golf or BMW I3, but they will pay for it and for less range too.

Even if there was a better car as honest John might call it I seriously would not want to pay for petrol or diesel again, nor would I want to drive one after driving the leaf.

If I were to have paid for all my electricity this year over 20,000 Kms i would have paid about 300 euro's to drive this distance on night rate electricity but I have got a lot free from the public charge points and now I have work charging so half my commute is free, below average my arse !

samih · 22-10-2015 9:06am

The "review" shouts out: "I wrote this on my lunch break based on a brief previous test drive and the press material and photos".

noelf · 22-10-2015 1:38pm

I actually thought the review was unfair to the car it isn't overpriced in relation to the egolf perhaps Nissan cut costs on interior to make it more affordable as regards the 152 golf mad-lad that I have its the best equipped one I have got many extras now standard with a very good 1.9 apr finance rate .. hope to change it in 2017 for a ev when the range of electric cars improves and battery charging time comes down ..

22-10-2015 2:47pm

Even the Golf Highline 1.6 TDI DSG costs 31K.

Doesn't have remote activation of AC or Heat, doesn't have LED lights or sat nav as standard.

410 for rear LED lights,

500 for heated seats. The leaf SVE includes heated front and rear seats.

A mental 1,600 for Bi-Xenon lights ? WTF !!!

Rear view camera 220

739 for Sat nav

The Golf higher spec interior is nicer though, but the Leaf includes leather which is a 2,000 option on the Golf.

cros13 · 22-10-2015 2:52pm

noelf wrote: »

I actually thought the review was unfair to the car it isn't overpriced in relation to the egolf perhaps Nissan cut costs on interior to make it more affordable as regards the 152 golf mad-lad that I have its the best equipped one I have got many extras now standard with a very good 1.9 apr finance rate .. hope to change it in 2017 for a ev when the range of electric cars improves and battery charging time comes down ..

It's certainly not expensive. Heck in Ireland the Leaf is a few thousand euro cheaper than a similarly equipped 1.6 Diesel Golf. And that's just looking at RRP excluding the Nissan scrappage deal.

I really disagree about the plastics, they're very solid. If you want to see flimsy plastic take a look at the new BMW 5 series interior.

22-10-2015 2:56pm

The Leaf plastics maybe cheap and hard but they're far from tacky and nasty. Leaf SVE is not a bad place to sit.

noelf · 22-10-2015 3:17pm

Sat nav rear view camera is standard also adaptive cruise control (excellent feature) and front and back rear sensors .. having cracked a head light on a previous golf €200 just for a new unit without fitting upgrading the front lights wasn't a risk that I was willing to take ..

22-10-2015 3:57pm

I didn't see sat nav or camera as standard on the options list ?

30 Kwh Leaf showing up on Nissan.ie

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