Range of two LEAFs very different in same 30 mile route

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avp

Member
Joined
Feb 8, 2014
Messages
18
Location
Alpedrete, Madrid, Spain
Hi.
I have a 2013 LEAF from october 13 with 42k (kms) (26k miles)and today we have just bought another one to my wife. The new one is a Demo and we got it in a Nissan dealer near Madrid. I checked the battery with LBA and the SOH was 90%. I didnt like it so much because my "old" one still have 92%. However the price was no bad and we bought the car. We got it this afternoon. The "new" one was 99% charged and while they were preparing the car I charged the "old" one with the ChaDeMo. In the moment we leave the dealer place the old one was 82%. There are 50 kms (31,2 miles) from the dealer to my house.
And now the result: My old LEAF reached my house with 28%, that is the comsumption was 82-28=54 %, what is perfectly normal because my house is 350 m aprox higher tan the dealer (the speed was 70-60 miles/h). The "new one" reached home with 8%!!!!!!!! Wow!!!!!, so the comsuption was 91%. The two cars were all the time at the same speed (always in tándem), the heater was fixed at the same temperatura, and everything else was the same. I called inmediatly to the dealer and the told me to go tomorrow with the to check the car. I told the dealer to put my money back inmediatly but the battery is still reporting 90% of SOH.
Why do you think could be the problem to have this so different comsuptions (91 vs 54) if the LBA SOH is very similar?
Thank you so much!!!
 
Alignment, tire pressure, tires, HVAC usage could all cause significant differences in efficiency and thus usage.

Did you happen to reset the efficiency meter on each car before the trip so you could confirm that the efficiency was similar over the drive?
 
As drees said, driving style could make a big difference. If your wife was following you, then she may have been on and off the throttle more to try to maintain the proper distance.

Another issue can be that the cell balancing can make a very big difference in range. The newer LEAFs (MY2013+) are reportedly better in this regard, but who knows?

Also, there have been several LEAFs out there with ~90% SOH when new which still would travel just as far on a range test as other cars with a SOH of 100%. However, doing that required driving quite a few of the miles below LBW and VLBW. Read this thread for more details.

Finally, the battery temperatures would have been quite different in your test. The demo LEAF you purchased may have been charged some time ago and cooled off while the battery in your old LEAF would have been warm when you arrived and would have warmed further as you charged on the ChaDeMo.
 
There's also the obvious question of battery calibration. A car that hasn't been driven much might not have a well calibrated battery. Meaning the instrumentation could be lying to you. There could be a lot more battery capacity left than the car is showing. In the same regard, there may be less available than the other car is showing. As the car is driven more, it may improve.
 
You haven't responded to Gary Gid's post concerning the apparently bad cell in the new car, from this post:

http://www.mynissanleaf.com/viewtopic.php?f=23&t=19001&p=409360#p409360" onclick="window.open(this.href);return false;

Could be the problem.
 
If LeafSpy is correct in the picture in that thread, then cell-pair 4 will NEVER become balanced because it is shunted while cell-pair 3 is the only one not shunted. Cell-pair 4 (and no other cell-pair) should be shunted. Perhaps the cell-pair mapping setting in LeafSpy is not set correctly. I seriously doubt that the LEAF is shunting the wrong cell-pair.

While cell-pair 4 may have a problem (such as a loose connection), it's also possible that it is simply out-of-balance with the rest of the pack.

I will note that the car has fewer than 900 km on it and it has only ever had 10 QCs and 14 L2 charge cycles.
 
Thank you for the answers.
After reading your expert opinions I tend to think that the problem could be this battery cell that seems to be "in bad condition".
I didnt check the battery temp but I have been driven the car in very different temperature conditions and the range affection has never been so big.
I didnt check the efficiency meter after the trip either. But I did check it this morning and the two cars had very similar efficiency with very different values of comsumption. This morning I drove the new one and my wife drove the old one, and again the comsumption of the new one was much higher (46% higher) which confirms that the driven style is not the reason. Most of the time I was driving in front, and the distance between the cars was big.

This morning we dropped the car in the Nissan dealer. They have been very nice because they stopped the purchase process until they find a solution to the problem. First of all they have offered us to check the battery and if the battery is ok, they offered us to use the car one week to check if the range is the same than in the other LEAF. If the result is negative, the offered us to change the car or put our money back. Those are great news for us. For these days they have given us another demo LEAF.
Finally, you are right DNAinaGoodWay, I didnt answer to Gary in the other thread. I m going to do it now. He seems to be right on his comment. Thanks.
 
DNAinaGoodWay said:
Could be the problem.
Definitely could be the problem - 3.976 V average is around 70% charged, but 3.903 V is around 50% charged.

RegGuheert said:
Perhaps the cell-pair mapping setting in LeafSpy is not set correctly.
I've suspected this based on what I've seen in LeafSpy. I should try to compare what it shows compared to LeafDD when the shunts are relatively stable.
 
RegGuheert said:
If LeafSpy is correct in the picture in that thread, then cell-pair 4 will NEVER become balanced because it is shunted while cell-pair 3 is the only one not shunted. Cell-pair 4 (and no other cell-pair) should be shunted. Perhaps the cell-pair mapping setting in LeafSpy is not set correctly. I seriously doubt that the LEAF is shunting the wrong cell-pair.

While cell-pair 4 may have a problem (such as a loose connection), it's also possible that it is simply out-of-balance with the rest of the pack.

I will note that the car has fewer than 900 km on it and it has only ever had 10 QCs and 14 L2 charge cycles.

Hi, thanks for your contribution to try too resolve this problema.
I would like to know what does "a shunted cell" exactly mean. From your comment I understand that shunted cells never become balanced. Also I have noticed that all these shunted cells are "orange" in the LBA while their values are negative in the Excel register file. In this car, the only non negative (and not shunted and no orange) cell is the cell number three.
Why cell 4 should be shunted and the only to be shunted. Because its value is the lowest one? Why some cells are shunted and others arent. (In my current LEAF there are a lot of cells shunted while others arent and they change all the time). Why do you think this can produce a battery capacity loss of about 40%-50%?
 
drees said:
DNAinaGoodWay said:
Could be the problem.
Definitely could be the problem - 3.976 V average is around 70% charged, but 3.903 V is around 50% charged.
Hi. How can you make the relation between the potencial value (in mV) and the battery capacity? Is there a formula or something like that?
Thank you very much!!
 
avp said:
drees said:
DNAinaGoodWay said:
Could be the problem.
Definitely could be the problem - 3.976 V average is around 70% charged, but 3.903 V is around 50% charged.
Hi. How can you make the relation between the potencial value (in mV) and the battery capacity? Is there a formula or something like that?
Thank you very much!!
A bunch of us have collected quite a bit of data from our LEAFs using LeafSpy. I can confirm that 3.903V is right around 50% SOC for my LEAF. That single cell will dictate how much capacity the entire car has. There are 96 cells stacked in series in the LEAF, but those cells are actually PAIRS of cells in parallel. I suspect that one of the two cells in that pair may have failed (open) and is not contributing to the overall capacity of the car.

I recommend that you run the car down to LBW and provide a screenshot of LeafSpy. It would be best if you get that picture JUST after the low cell drops below 3.712V. Then we can calculate whether or not Nissan believes that is a failed cell-pair. (This test is known as the Cell Voltage Loss Inspection (CVLI).)

While the dealership can replace the module which contains the (likely) bad cell, personally I would not want the dealer opening the sealed battery in my new LEAF. Better to have a fresh one from the factory, IMO.
 
A bunch of us have collected quite a bit of data from our LEAFs using LeafSpy. I can confirm that 3.903V is right around 50% SOC for my LEAF. That single cell will dictate how much capacity the entire car has. There are 96 cells stacked in series in the LEAF, but those cells are actually PAIRS of cells in parallel. I suspect that one of the two cells in that pair may have failed (open) and is not contributing to the overall capacity of the car.

I recommend that you run the car down to LBW and provide a screenshot of LeafSpy. It would be best if you get that picture JUST after the low cell drops below 3.712V. Then we can calculate whether or not Nissan believes that is a failed cell-pair. (This test is known as the Cell Voltage Loss Inspection (CVLI).)

While the dealership can replace the module which contains the (likely) bad cell, personally I would not want the dealer opening the sealed battery in my new LEAF. Better to have a fresh one from the factory, IMO.

Ok. Thanks a lot!!! Tomorrow I,ll do it. First in LBW and then when it reaches 3.712 mV.
Is this CVLI something official in Nissan? Today the dealer technician told me that this cell was low but not low enogh to be considered a bad cell. They have no idea about EVs. He showed me that GOM indicated 132 km (82,5 miles), as an evidence of battery health!!!
Today, after starting at 100% and driving 57,7 km (36 miles) the battery was at 6%. I continued to turtle. 77,8 km (48,6 m) Average speed: 100 km/h (62,5 m/h). Outside temp: 0C. In those conditions my current LEAF ranges 110-120 kms (69-75 miles).
To be continued...
 
avp said:
Ok. Thanks a lot!!! Tomorrow I,ll do it. First in LBW and then when it reaches 3.712 mV.
Is this CVLI something official in Nissan?
Yes, but not if we do it. Only if THEY do it. It is directly from the LEAF service manual.
avp said:
Today the dealer technician told me that this cell was low but not low enogh to be considered a bad cell.
We have had several accounts of LEAF technicians doing CVLI at high voltages where it really does not apply. Again, the best way to know if that cell needs to be replaced is to calculate CVLI when the lowest cell is JUST below 3.712V. Post your LeafSpy picture here and we can give you specific advice about how to approach your dealership. Will it help? I suppose that depends on the dealership (and Nissan).
 
RegGuheert said:
I recommend that you run the car down to LBW and provide a screenshot of LeafSpy. It would be best if you get that picture JUST after the low cell drops below 3.712V. Then we can calculate whether or not Nissan believes that is a failed cell-pair. (This test is known as the Cell Voltage Loss Inspection (CVLI).)
Well, I did it. The low cell got 3.712 mV a few kilometers after LBW. LBW was at 20% (dasboard) while level 3.712 mV was reached when dashboard indicated 12%.



I was surprised because when dashboard was 12% SOC was 41,6 %



I also logged everything in the .csv file that LBA generates.

I started the test al 78%. The first strange thing was that turtle mode continued with battery charged at 78%



I turned off the car and turned it on again and the turtle mode dissappeared. But after 15 kilometers I turned off and on the car again and the turtle mode appeared again for a while.

Finally I reached home again after 29,5 kilometers (18,43 miles) with 12 % in the dashboard (from 78% to 12% in 18,43 miles). Wow!!



I am going to get the car back to the dealer on Monday. It is a possibility that they offer to me to repair this bad cell but I dont know if the rest of the battery may have had any extra effort due to this problem.
 
Cell pair 4 is clearly unbalanced. It is red because the shunt order is wrong (it should be 8421). It is possible that with (long) time the other cells could discharge and reach the same level of CP4, but I think it is very strange to have this sort of unbalance. Probably CP4 is damaged with a relatively high self discharge, and it should be exchanged.

I know a case in Portugal of a 2011 Leaf that charged from 80% SOC to a 100% charge about 0.5kW.h (at the time there was no LS) and shortly after that the owner got a call from Nissan to exchange one module (it charged from dead to 100% about 14kW.h from the wall). The LBC certainly tried to balance the pack, but the self discharge in the bad CP was probably higher than the extremely low balance current of the LBC. After the exchange everythink became normal for a 2 year old pack (about 88% SOH).

If they don't exchange the module now, don't keep the car. It will be a PITA until Nissan finally accepts to fix the battery.
 
RegGuheert said:
I recommend that you run the car down to LBW and provide a screenshot of LeafSpy. It would be best if you get that picture JUST after the low cell drops below 3.712V. Then we can calculate whether or not Nissan believes that is a failed cell-pair. (This test is known as the Cell Voltage Loss Inspection (CVLI).

Once I have the information about this moment when min cell reached 3.712 mV, How can I calculate whether or not it is a failed pair?
 
Nice job capturing the data *exactly* at 3.712V! That makes it difficult for Nissan to try to claim there is no issue.

Nissan's calculation for CVLI is somewhat convoluted, but I'll use their exact terminology so that OP can share it directly with the dealer in terms that should be familiar from the service manual.

2011 Nissan LEAF Service Manual Revision: 2011 April - Page EVB65 said:
CELL VOLTAGE LOSS INSPECTION

Description

The cell voltage loss inspection is performed is performed to identify cells that the cell voltage is on the decrease (although not judged a malfunction in DTC) and this may lead to a malfunction, if left stand.
This inspection identifies a cell voltage which is standard value or less when the minimum cell voltage is 3,712mV or less.
A module including a cell voltage identified by this inspection must be replaced with a new one to prevent malfunction.

Inspection Method
Skipping section explaining how to do this with CONSULT doing all the calculations.
2011 Nissan LEAF Service Manual Revision: 2011 April - Page EVB66 said:
CHECKING CELL VOLTAGE LOSS WITHOUT USING "WORK SUPPORT" OF CONSULT

1. PERFORM CELL VOLTAGE LOSS INSPECTION
With CONSULT
a. Select "DATA MONITOR" OF "HV BAT."
b. Check "MINIMUM CELL VOLTAGE."

Is "MINIMUM CELL VOLTAGE" 3,712 mV or less?
YES >> GO TO 3.
NO >> GO TO 2.
You are using LeafSpy instead of CONSULT and your MINIMUM CELL VOLTAGE is *exactly* 3,712 mV, so I will not type step 2 showing how to lower the voltage using the heater.
2011 Nissan LEAF Service Manual Revision: 2011 April - Page EVB67 said:
3. CALCULATE CELL VOLTAGE LOSS JUDGEMENT VALUE
With CONSULT
1. Check "DATA MONITOR" and record "TOTAL BATTERY VOLTAGE" and "MAXIMUM CELL VOLTAGE"
2. Calculate cell voltage loss judgment value.

Cell voltage loss judgment value = (2.5 x A - 0.144 x B) / 96
A = "TOTAL BATTERY VOLTAGE" (V)
B = "MAXIMUM CELL VOLTAGE" (mV)


NOTE:
The above equation of cell voltage loss judgment value is the simplified version of the following equation.
1. Calculate the average value of cell voltage by dividing "TOTAL BATTERY VOLTAGE" by 96 (the number of cells)

Average cell voltage = "TOTAL BATTERY VOLTAGE" / 96
Of course, LeafSpy gave you this value directly:

3.851V
2011 Nissan LEAF Service Manual Revision: 2011 April - Page EVB67 said:
2. Calculate cell voltage loss judgment value.

Cell voltage loss judgment value = Average cell voltage - ("MAXIMUM CELL VOLTAGE - Average cell voltage) x 1.5
From LeafSpy, we get:

Cell voltage loss judgment value = 3.851V - (3.861V - 3.851V) x 1.5 = 3.836V
2011 Nissan LEAF Service Manual Revision: 2011 April - Page EVB67 said:
>> GO TO 4.

4. JUDGE CELL OF VOLTAGE LOSS
With CONSULT
a. Record "CELL VOLTAGE 1-96" with "DATA MONITOR".
b. Check to see if there is "CELL VOLTAGE" which is less than or equal to the judgment value.

OK: Cell voltage loss judgment value < CELL VOLTAGE 1 - 96
NG: Cell voltage loss judgment value > CELL VOLTAGE 1 - 96


Is there a cell voltage which is the judgment value or less?
YES >> Replace module including cell voltage the judgment value or less. Refer to [EVB-153, "Exploded View"
NO >> INSPECTION END
3.836V is significantly higher than the voltage of your cell-pair 4, which is 3.712V. This is the clearest case of a failure of this test that I have seen. Since this is a new car, my opinion is that your cell-pair 4 has a manufacturing defect of some sort and needs to be replaced. (I have had a few occasions when I have had a cell fail this test, but the failure was much more marginal and was simply due to cell imbalance and later the issues corrected themselves, so I have not reported any issue to my dealer. In your case, the test was done in the optimum condition and one cell is clearly far below the rest of the pack.)

I have posted information in this thread which explains which cell-pairs are located in which modules and where they are located in the LEAF's battery. Basically, cell-pair 4 is in module MD2, which is located in the rear stack under the back seat, second from the right side of the car.

If you still have the option, I would recommend returning the car. If not, then it seems clear Nissan should replace the failed module under the terms of the warranty. Their own service manual says:
2011 Nissan LEAF Service Manual Revision: 2011 April - Page EVB66 said:
A module including a cell voltage identified by this inspection must be replaced with a new one to prevent malfunction.
 
RegGuheert said:
Nice job capturing the data *exactly* at 3.712V! That makes it difficult for Nissan to try to claim there is no issue.

Nissan's calculation for CVLI is somewhat convoluted, but I'll use their exact terminology so that OP can share it directly with the dealer in terms that should be familiar from the service manual.

2011 Nissan LEAF Service Manual Revision: 2011 April - Page EVB65 said:
CELL VOLTAGE LOSS INSPECTION

Description

The cell voltage loss inspection is performed is performed to identify cells that the cell voltage is on the decrease (although not judged a malfunction in DTC) and this may lead to a malfunction, if left stand.
This inspection identifies a cell voltage which is standard value or less when the minimum cell voltage is 3,712mV or less.
A module including a cell voltage identified by this inspection must be replaced with a new one to prevent malfunction.

Inspection Method
Skipping section explaining how to do this with CONSULT doing all the calculations.
2011 Nissan LEAF Service Manual Revision: 2011 April - Page EVB66 said:
CHECKING CELL VOLTAGE LOSS WITHOUT USING "WORK SUPPORT" OF CONSULT

1. PERFORM CELL VOLTAGE LOSS INSPECTION
With CONSULT
a. Select "DATA MONITOR" OF "HV BAT."
b. Check "MINIMUM CELL VOLTAGE."

Is "MINIMUM CELL VOLTAGE" 3,712 mV or less?
YES >> GO TO 3.
NO >> GO TO 2.
You are using LeafSpy instead of CONSULT and your MINIMUM CELL VOLTAGE is *exactly* 3,712 mV, so I will not type step 2 showing how to lower the voltage using the heater.
2011 Nissan LEAF Service Manual Revision: 2011 April - Page EVB67 said:
3. CALCULATE CELL VOLTAGE LOSS JUDGEMENT VALUE
With CONSULT
1. Check "DATA MONITOR" and record "TOTAL BATTERY VOLTAGE" and "MAXIMUM CELL VOLTAGE"
2. Calculate cell voltage loss judgment value.

Cell voltage loss judgment value = (2.5 x A - 0.144 x B) / 96
A = "TOTAL BATTERY VOLTAGE" (V)
B = "MAXIMUM CELL VOLTAGE" (mV)


NOTE:
The above equation of cell voltage loss judgment value is the simplified version of the following equation.
1. Calculate the average value of cell voltage by dividing "TOTAL BATTERY VOLTAGE" by 96 (the number of cells)

Average cell voltage = "TOTAL BATTERY VOLTAGE" / 96
Of course, LeafSpy gave you this value directly:

3.851V
2011 Nissan LEAF Service Manual Revision: 2011 April - Page EVB67 said:
2. Calculate cell voltage loss judgment value.

Cell voltage loss judgment value = Average cell voltage - ("MAXIMUM CELL VOLTAGE - Average cell voltage) x 1.5
From LeafSpy, we get:

Cell voltage loss judgment value = 3.851V - (3.861V - 3.851V) x 1.5 = 3.836V
2011 Nissan LEAF Service Manual Revision: 2011 April - Page EVB67 said:
>> GO TO 4.

4. JUDGE CELL OF VOLTAGE LOSS
With CONSULT
a. Record "CELL VOLTAGE 1-96" with "DATA MONITOR".
b. Check to see if there is "CELL VOLTAGE" which is less than or equal to the judgment value.

OK: Cell voltage loss judgment value < CELL VOLTAGE 1 - 96
NG: Cell voltage loss judgment value > CELL VOLTAGE 1 - 96


Is there a cell voltage which is the judgment value or less?
YES >> Replace module including cell voltage the judgment value or less. Refer to [EVB-153, "Exploded View"
NO >> INSPECTION END
3.836V is significantly higher than the voltage of your cell-pair 4, which is 3.712V. This is the clearest case of a failure of this test that I have seen. Since this is a new car, my opinion is that your cell-pair 4 has a manufacturing defect of some sort and needs to be replaced. (I have had a few occasions when I have had a cell fail this test, but the failure was much more marginal and was simply due to cell imbalance and later the issues corrected themselves, so I have not reported any issue to my dealer. In your case, the test was done in the optimum condition and one cell is clearly far below the rest of the pack.)

I have posted information in this thread which explains which cell-pairs are located in which modules and where they are located in the LEAF's battery. Basically, cell-pair 4 is in module MD2, which is located in the rear stack under the back seat, second from the right side of the car.

If you still have the option, I would recommend returning the car. If not, then it seems clear Nissan should replace the failed module under the terms of the warranty. Their own service manual says:
2011 Nissan LEAF Service Manual Revision: 2011 April - Page EVB66 said:
A module including a cell voltage identified by this inspection must be replaced with a new one to prevent malfunction.

Now, after your excellent research, I think it is clear that the car (the battery) is in bad condition. It is incredible that the dealer did an "official battery inspection and battery test" and they didn't find anything wrong. In my opinión spanish dealers are not prepared yet to manage this kind of cars. The personnel is not trained to do that and the result is not good at all. Owners use to know much more about EVs tan dealers.
Tomorrow We are going to give them the car back. If they offer us another one with similar cost and mileage we will get it. Otherwise we have to find other option.
Thank you very much for your help!!!
 
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