Possible Widespread 2018-19 Traction Battery Quick Charge Problems

Doesn't it throttle at about 20KW or still 3x faster than L2 charging on a new leaf?

If correct that is still x5 or x6 the speed my 3.x KW on board charger does. I drove back from NC on purchase of my used leaf 3 years ago with 2 chademo sessions and some Level 2 action (about 210 miles one way).

I wouldn't have needed as many chademo sessions if the 40 kWh pack gets me near twice as far per charge. I'd probably just make it home without doing any L2 with that pack.

I can't see buying a brand new Leaf with no TMS but if they put new packs in them when they hit 8 bars it might be an upgrade for us 24 kWh Leafers when the day comes you can get a 40 kWh Leaf under $10,000.

dhanson865 said:

Doesn't it throttle at about 20KW or still 3x faster than L2 charging on a new leaf?

If correct that is still x5 or x6 the speed my 3.x KW on board charger does. I drove back from NC on purchase of my used leaf 3 years ago with 2 chademo sessions and some Level 2 action (about 210 miles one way).

I wouldn't have needed as many chademo sessions if the 40 kWh pack gets me near twice as far per charge. I'd probably just make it home without doing any L2 with that pack.

I can't see buying a brand new Leaf with no TMS but if they put new packs in them when they hit 8 bars it might be an upgrade for us 24 kWh Leafers when the day comes you can get a 40 kWh Leaf under $10,000.

Click to expand...

you wouldn't have an issue....maybe 210 miles is one QC stop. But who knows? You might be limited to 20 kw based on ambient temps. Realize the LEAF has not seen Summer yet anywhere

DaveinOlyWA said:

you wouldn't have an issue....maybe 210 miles is one QC stop. But who knows? You might be limited to 20 kw based on ambient temps. Realize the LEAF has not seen Summer yet anywhere

Click to expand...

So ~20 KW means that Chademo stop might be 1.5 to 2 hours depending on how low you got.

What was it at best ~50 KW taking 45 minutes to fill up?

dhanson865 said:

DaveinOlyWA said:

you wouldn't have an issue....maybe 210 miles is one QC stop. But who knows? You might be limited to 20 kw based on ambient temps. Realize the LEAF has not seen Summer yet anywhere

Click to expand...

So ~20 KW means that Chademo stop might be 1.5 to 2 hours depending on how low you got.

What was it at best ~50 KW taking 45 minutes to fill up?

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Oh no chance! Highest SOC for ramp down I have seen is 60% SOC. My S 30 averaged 46 KW once but that was on 125 amp AV starting at 5% SOC.

Filling up at DCFC is a fool's game. Wouldn't even guess as to how long it would take. I watched a LEAF (24 kwh I believe) go from 90% to done in just about 15 minutes. Guessing it likely stopped around 94-95%

The issue is real, Some QC charging stations charge by the minute, so it is not only our time is wated, our money is wasted, while waiting. Here is my experience on a 80F-85F day, doing 2 - QCs. 1st QC started slowing down around 60%. 2nd QC was slow all the way when my battery was at 20%. However my battery gauge on car never hit RED. Leaf SPY temp. was 112F after the 2nd QC.

Check out my Leaf Spy graphs. (Not looking good). Issue for Nissan is probably they can't fix this on software. They need a way to cool the battery. When you charge batteries heat up. Higher the density, more heat it generate, and need to decipate. (40kWh battery same size as 24kWh)


First QC Graph
https://drive.google.com/open?id=11NoxZKQ3CXQrTPmpiHxEzZ42Ze3MzWhf

Second QC Graph
https://drive.google.com/open?id=1185z8Jfu4FAhQvL_D5mxrx6LwIP6dRHV

borugee said:

The issue is real, Some QC charging stations charge by the minute, so it is not only our time is wated, our money is wasted, while waiting. Here is my experience on a 80F-85F day, doing 2 - QCs. 1st QC started slowing down around 60%. 2nd QC was slow all the way when my battery was at 20%. However my battery gauge on car never hit RED. Leaf SPY temp. was 112F after the 2nd QC.

Check out my Leaf Spy graphs. (Not looking good). Issue for Nissan is probably they can't fix this on software. They need a way to cool the battery. When you charge batteries heat up. Higher the density, more heat it generate, and need to decipate. (40kWh battery same size as 24kWh)


First QC Graph
https://drive.google.com/open?id=11NoxZKQ3CXQrTPmpiHxEzZ42Ze3MzWhf

Second QC Graph
https://drive.google.com/open?id=1185z8Jfu4FAhQvL_D5mxrx6LwIP6dRHV

Click to expand...

Thanks for your data. It is very interesting to finally hear about problems on the US model of the 40 kWh LEAF II.

But to get a detailed picture, I would need more information like:

Are you sure that this particular charger can deliver 45 to 50 kW to your 40 kWh LEAF? Does it do so on your 30 kWh LEAF?

Do you have LeafSpy Pro logs about several complete charges from low battery (10-20%) up to some 80% SOH?

Thank you very much for your help.

cwleaf2 said:

Thanks for your data. It is very interesting to finally hear about problems on the US model of the 40 kWh LEAF II.

But to get a detailed picture, I would need more information like:

Are you sure that this particular charger can deliver 45 to 50 kWh to your 40 kWh LEAF? Does it do so on your 30 kWh LEAF?

Click to expand...

Charge rate is measured in kW, not kWh. You have the units correct for battery capacity.

cwerdna said:

cwleaf2 said:

Thanks for your data. It is very interesting to finally hear about problems on the US model of the 40 kWh LEAF II.

But to get a detailed picture, I would need more information like:

Are you sure that this particular charger can deliver 45 to 50 kW to your 40 kWh LEAF? Does it do so on your 30 kWh LEAF?

Click to expand...

Charge rate is measured in kW, not kWh. You have the units correct for battery capacity.

Click to expand...

Sorry, typo - corrected!

Given the weasel wording in the Owner's manual, it's pretty clear the aggressive charge rate throttling is by design. Pretty cynical of Nissan to not make this clear to prospective buyers, particularly to naive first time EV buyers...

It wouldn't be a deal breaker for me personally, and it might even result in quicker depreciation of 2018s once word spreads to the broader EV community. As a result, I'm hopefully that I'll get a good deal on a used 2018 in a few years.

Pretty brutal though for people who've taken the plunge and purchased a 2018, trusting that Nissan would have disclosed something like this.

Yes am seeing all the attention this is getting #rapidgate. Some good data is coming but definitely I feel is deliberate safety feature put in by Nissan to prolong battery life.

I agree, for many people this will not be a deal breaker, however also agree Nissan should say something and they can spin this into a positive. I'm hoping that maybe they can tweak software to not restrict rapid charging as much during second or third or even 4th. Ease up a bit on the throttling back of charging input. I would think after 4 successive rapid charges, I would want to take a break and rest overnight somewhere as well as let the pack cool down.

Seems all the theories are similar in the fact that Nissan packed more cells into the same space (good=more energy density), however will less modules (good=saves some weight) seems the heat build up can dissipate enough with the passive cooling (bad=higher battery temps, bad=need more time for the pack to cool after rapid charge). I thought that the chemistry change would help with heat build up, but it seems to have not to as much.

Many YouTubers are talking about this and we will also mention it on our next show coming up in a few days (Model 3 Owners Club - but name is changing this next show!). Check it out.

I'm actually going to be meeting with some Nissan Canada and North America execs next month and hope they will respond with some positive news on this.

Regardless, for my driving needs, the new Leaf works and I am not cancelling my order.

Seems all the theories are similar in the fact that Nissan packed more cells into the same space

Click to expand...

No. The number of cells, and thus the voltage, is the same. Each cell holds more energy, thus producing a higher capacity. People seem to find this hard to understand, so think of it as replacing 2 AA carbon-zinc cells in a little flashlight with two AA alkaline cells. Same number of cells, same size, same voltage, but more energy available.

LeftieBiker said:

Seems all the theories are similar in the fact that Nissan packed more cells into the same space

Click to expand...

No. The number of cells, and thus the voltage, is the same. Each cell holds more energy, thus producing a higher capacity. People seem to find this hard to understand, so think of it as replacing 2 AA carbon-zinc cells in a little flashlight with two AA alkaline cells. Same number of cells, same size, same voltage, but more energy available.

Click to expand...

While it is true that there are no additional cells in the 2018 LEAF battery, the fact is that the cells are thicker than they were in previous versions. They are also packaged differently within the modules (8 cells per module instead of 4) and the modules are arranged differently within the pack in order to take advantage of empty space that was there. The bottom line is that they figured out out to fit more stuff into the same box.

RegGuheert said:

LeftieBiker said:

Seems all the theories are similar in the fact that Nissan packed more cells into the same space

Click to expand...

No. The number of cells, and thus the voltage, is the same. Each cell holds more energy, thus producing a higher capacity. People seem to find this hard to understand, so think of it as replacing 2 AA carbon-zinc cells in a little flashlight with two AA alkaline cells. Same number of cells, same size, same voltage, but more energy available.

Click to expand...

While it is true that there are no additional cells in the 2018 LEAF battery, the fact is that the cells are thicker than they were in previous versions. They are also packaged differently within the modules (8 cells per module instead of 4) and the modules are arranged differently within the pack in order to take advantage of empty space that was there. The bottom line is that they figured out out to fit more stuff into the same box.

Click to expand...

And apparently none of the (apparently theoretical) "passive cooling" magic they tried to dazzle us with after the last battery debacle. Or at least no effective passive cooling. If you can't cool the pack in 2 hours of mild driving in a below-freezing British winter, then your passive cooling design sucks donkey balls.

https://youtu.be/QKlLuPLgKn0

cwleaf2 said:

borugee said:

The issue is real, Some QC charging stations charge by the minute, so it is not only our time is wated, our money is wasted, while waiting. Here is my experience on a 80F-85F day, doing 2 - QCs. 1st QC started slowing down around 60%. 2nd QC was slow all the way when my battery was at 20%. However my battery gauge on car never hit RED. Leaf SPY temp. was 112F after the 2nd QC.

Check out my Leaf Spy graphs. (Not looking good). Issue for Nissan is probably they can't fix this on software. They need a way to cool the battery. When you charge batteries heat up. Higher the density, more heat it generate, and need to decipate. (40kWh battery same size as 24kWh)


First QC Graph
https://drive.google.com/open?id=11NoxZKQ3CXQrTPmpiHxEzZ42Ze3MzWhf

Second QC Graph
https://drive.google.com/open?id=1185z8Jfu4FAhQvL_D5mxrx6LwIP6dRHV

Click to expand...

Thanks for your data. It is very interesting to finally hear about problems on the US model of the 40 kWh LEAF II.

But to get a detailed picture, I would need more information like:

Are you sure that this particular charger can deliver 45 to 50 kW to your 40 kWh LEAF? Does it do so on your 30 kWh LEAF?

Do you have LeafSpy Pro logs about several complete charges from low battery (10-20%) up to some 80% SOH?

Thank you very much for your help.

Click to expand...

The charge is from a EVGO DCFC charger, I don't have 30kWh LEAF anymore. But I have charged from the same charger before and remember charge speed of 36kW (Start of charging when battery is low) to 40kW (When battery get close to 80%) sustained on this charger and then start to drop.

I have charged few times as the 1st charge on a DCFC and those times, charge rate started dropping around 65% battery on 40kWh car. I don't have logs on Leaf Pro for these.

First charge (or actually any charge) where batt temps are below 90º F will start at or near full speed with the ramp down starting between 55 - 64%.

The interesting thing is the warmer the pack at the start, the later the ramp down. On a cold pack, ramp down starts at 55% the "actual" temp doesn't seem to matter.

The other day, I did 3 QC's


first one; batt temps started in mid 50's, ended in low 90's. SOC 4 - 57%. ramp down 54%.

2nd one; batt temps 85-90º, ended 115º SOC 27- 78% ramp down 64%

3rd one (not expecting much) batt temps started 113, ended at 115 (batt temps on charge graph was nearly flat from halfway thru 2nd charge)

started at 22 KW (65 amps) charged 23 mins, SOC 75-91% (59 amps)

Thought about putting more mileage between charge 2 and 3 but the temps were dropping too fast and without AV there is no convenient QC farther down the road...

DaveinOlyWA said:

first one; batt temps started in mid 50's, ended in low 90's. SOC 4 - 57%. ramp down 54%.

2nd one; batt temps 85-90º, ended 115º SOC 27- 78% ramp down 64%

3rd one (not expecting much) batt temps started 113, ended at 115 (batt temps on charge graph was nearly flat from halfway thru 2nd charge)

started at 22 KW (65 amps) charged 23 mins, SOC 75-91% (59 amps)

Click to expand...

That doesn't look horrible to me. It seems that Nissan has decided they don't want the battery temperature to go above 115F.

At a charging rate of 22 kW, the battery "hot spot" temperature is certainly above 115F, perhaps as high as 150F. I don't know about NMC622, but some Li-ion batteries have temperatures above which VERY bad things happen. In this case, it's more likely Nissan just wants to limit the highest temperatures that the hottest cells in the pack will see during charging in order to limit their degradation rate relative to the coolest cells. Remember, the pack's capacity is roughly the capacity of the worst cell-pair times the number of cell-pairs.

RegGuheert said:

DaveinOlyWA said:

first one; batt temps started in mid 50's, ended in low 90's. SOC 4 - 57%. ramp down 54%.

2nd one; batt temps 85-90º, ended 115º SOC 27- 78% ramp down 64%

3rd one (not expecting much) batt temps started 113, ended at 115 (batt temps on charge graph was nearly flat from halfway thru 2nd charge)

started at 22 KW (65 amps) charged 23 mins, SOC 75-91% (59 amps)

Click to expand...

That doesn't look horrible to me. It seems that Nissan has decided they don't want the battery temperature to go above 115F.

At a charging rate of 22 kW, the battery "hot spot" temperature is certainly above 115F, perhaps as high as 150F. I don't know about NMC622, but some Li-ion batteries have temperatures above which VERY bad things happen. In this case, it's more likely Nissan just wants to limit the highest temperatures that the hottest cells in the pack will see during charging in order to limit their degradation rate relative to the coolest cells. Remember, the pack's capacity is roughly the capacity of the worst cell-pair times the number of cell-pairs.

Click to expand...

agreed. Here you see still charging at 35 KW when temps first hit 115º. So stop charge, go 15 miles down road, start charge at nearly same temp and it drops to 22 KW (see gap on green line) so its looking like starting temp is key.

2nd charge batt temps 84.3/89.2/90.4

https://photos.app.goo.gl/iVrVaPlPnQNh4fcI2

DaveinOlyWA said:

RegGuheert said:

DaveinOlyWA said:

first one; batt temps started in mid 50's, ended in low 90's. SOC 4 - 57%. ramp down 54%.

2nd one; batt temps 85-90º, ended 115º SOC 27- 78% ramp down 64%

3rd one (not expecting much) batt temps started 113, ended at 115 (batt temps on charge graph was nearly flat from halfway thru 2nd charge)

started at 22 KW (65 amps) charged 23 mins, SOC 75-91% (59 amps)

Click to expand...

That doesn't look horrible to me. It seems that Nissan has decided they don't want the battery temperature to go above 115F.

At a charging rate of 22 kW, the battery "hot spot" temperature is certainly above 115F, perhaps as high as 150F. I don't know about NMC622, but some Li-ion batteries have temperatures above which VERY bad things happen. In this case, it's more likely Nissan just wants to limit the highest temperatures that the hottest cells in the pack will see during charging in order to limit their degradation rate relative to the coolest cells. Remember, the pack's capacity is roughly the capacity of the worst cell-pair times the number of cell-pairs.

Click to expand...

agreed. Here you see still charging at 35 KW when temps first hit 115º. So stop charge, go 15 miles down road, start charge at nearly same temp and it drops to 22 KW (see gap on green line) so its looking like starting temp is key.

2nd charge batt temps 84.3/89.2/90.4

https://photos.app.goo.gl/iVrVaPlPnQNh4fcI2

Click to expand...

Thanks for your rapid charging graph! This is exactly the same problem as we saw on your LEAF 2.0 in Europe.

Here are the numbers from Bjørn's 600 mile yesterday in Norway:

Second charge:
T1: 32,0º T2: 29,7º T3: 22,5º SOC: 16,1% Charge: 42.6 kW
T1: 40,4º T2: 38,9º T3: 30,6º SOC: 42,4% Charge: 44.4 kW
T1: 44,0º T2: 42,6º T3: 34,1º SOC: 54,3% Charge: 45.0 kW
T1: 47,9º T2: 46,6º T3: 37,9º SOC: 68,5% Charge: 36.2 kW
T1: 48,3º T2: 47,0º T3: 38,4º SOC: 70,8% Charge: 34.3 kW

Third charge:
T1: 45,4º T2: 41,8º T3: 32,6º SOC: 48,7% Charge: 22.1 kW
T1: 46,6º T2: 42,7º T3: 33,3º SOC: 56,1% Charge: 21.1 kW

Later charge:
T1: 41,0º T2: 34,4º T3: 23,5º SOC: 34,9% Charge: 25.9 kW
T1: 44,4º T2: 37,7º T3: 26,6º SOC: 54,7% Charge: 26.1 kW
T1: 46,0º T2: 39,2º T3: 28,5º SOC: 64,4% Charge: 26.0 kW

Latest charge:
T1: 37,1º T2: 29,6º T3: 18,4º SOC: 15,1% Charge: 30.9 kW
T1: 42,9º T2: 36,2º T3: 25,7º SOC: 52,2% Charge: 29.7 kW
T1: 44,4º T2: 37,8º T3: 27,6º SOC: 60,9% Charge: 29.2 kW

Last charge:
T1: 39,6º T2: 32,7º T3: 22,2º SOC: 21,8% Charge: 26.1 kW
T1: 42,3º T2: 35,3º T3: 24,8º SOC: 48,0% Charge: 26.4 kW
T1: 44,3º T2: 37,3º T3: 26,7º SOC: 59,2% Charge: 27.0 kW

So Nissan has decided to protect the battery from excessive temperatures by limiting charge rate on successive fast charges. Seems like a a good idea.

The problem is that the packs will experience similarly high temps in Summer with NO QC.