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Discussion Starter · #1 ·
I have established via Lspy that my 2015 24Kw traction battery is suffering from a weak cell, I have opened a case with Nissan but it is in the early stages.
What I need to know from anyone who has been through this process is:
1. What diagnostic tests did Nissan carry out to confirm that there was a weak cell
2. Did you have to pay for the diagnostics and if so was the cost refunded once the weak cell was confirmed.
3. Once the weak cell was confirmed by Nissan what happened next.

TIA
 

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Leaf 30kWh, Outlander PHEV
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This should help

- Leaf 30 kWh
Sent from mobile phone so please mind the typos
 

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Discussion Starter · #3 ·
This should help

- Leaf 30 kWh
Sent from mobile phone so please mind the typos
Seen all those threads nothing really mentioned about what Nissan does, I dont want to pay for diagnostics if my local dealer is not going to find the issue.
At what level does it become a warrantable defect as at present no DTC codes have been triggered.
The thing is I am losing my faith in the cars ability to get me from A to B.
Yesterday showed 62 miles on gom I actually did 24.9 miles and had the lbw come on at 18 miles and ended up with 16 miles remaining on the gom so somewhere 20 miles worth of range just evaporated !
The 25 miles i did was without any auxillary drain like aircon etc low speed mainly around town.
 

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Leaf 30kWh, Outlander PHEV
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Seen all those threads nothing really mentioned about what Nissan does, I dont want to pay for diagnostics if my local dealer is not going to find the issue.
At what level does it become a warrantable defect as at present no DTC codes have been triggered.
The thing is I am losing my faith in the cars ability to get me from A to B.
Yesterday showed 62 miles on gom I actually did 24.9 miles and had the lbw come on at 18 miles and ended up with 16 miles remaining on the gom so somewhere 20 miles worth of range just evaporated !
The 25 miles i did was without any auxillary drain like aircon etc low speed mainly around town.
Your issue isn't much different from thread I mentioned. Nissan did nothing. Good luck with yours.

As fast as I know, Nissan only look at SoH and nothing else

- Leaf 30 kWh
Sent from mobile phone so please mind the typos
 

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Discussion Starter · #5 ·
Your issue isn't much different from thread I mentioned. Nissan did nothing. Good luck with yours.

As fast as I know, Nissan only look at SoH and nothing else

- Leaf 30 kWh
Sent from mobile phone so please mind the typos
There are many faults that could occur with the battery pack that wont affect the SOH im sure Nissan would do a more in depth diagnosis if you were complaining of a decreased range, there is a specific procedure in their maintenance manual titled "Reduction In Driving Range" however it is pretty straight forward:

REDUCTION IN THE DRIVING RANGE
EVB-179
< SYMPTOM DIAGNOSIS >

SYMPTOM DIAGNOSIS
REDUCTION IN THE DRIVING RANGE
Description INFOID:0000000010640649
• The driving range is shorter than before.
• Sudden change (decrease/increase) in possible travel distance indicated on the combination meter.
Diagnosis Procedure INFOID:0000000010640650
1.CHECK LI-ION BATTERY AVAILABLE CHARGE GAUGE
Check the indication of the Li-ion battery available charge gauge.
NOTE:
Check 12 segments for lighting status.
Is the lighting status 1 Segment or none?
YES >> GO TO 3.
NO >> GO TO 2.
2.DISCHARGE OF LI-ION BATTERY
1. Set the vehicle to READY.
2. Set the vehicle, according to the following conditions.
3. Let the Li-ion battery discharge until the Li-ion battery available charge gauge shows Segment 1 or below.
> GO TO 3.
3.CHARGE OF LI-ION BATTERY
1. Charge the Li-ion battery by normal charge until the level reaches full charge.
2. After the completion of normal charge, check that the indication of the Li-ion battery available charge
gauge shows 12 segments.
> GO TO 4.
4.PERFORM DTC CONFIRMATION PROCEDURE
With CONSULT
1. Power switch ON and wait for 10 seconds or more.
2. Select “Self Diagnostic Result” of “HV BAT”.
3. Check DTC.
Is any DTC detected?
YES
NO
>> Perform diagnosis on the detected DTC. Refer to EVB-45, "DTC Index".
> INSPECTION END

Does Nissan's "Consult " diagnosis software see a lot more DTC's than what leaf spy reports, I feel sure it would but ultimately if it doesnt how do you convince them to carry out an in depth battery diagnosis.
Theres a mention of minimum cell voltage of 3.712mV and 30mV maximum divergance, even mathmatical equations to determine cell voltage and what module to replace.
It just getting them to look at it and do the right test
 

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Leaf 30kWh, Outlander PHEV
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2.7V or 3.7v?

3.7 is stable voltage for Li-ion NMC and various flavours of it. Even fully depleted cell would return to 3.7V under no load

I don't see anything that measures real world range.

- Leaf 30 kWh
Sent from mobile phone so please mind the typos
 

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Discussion Starter · #7 · (Edited)
My take on it is they discharge until the minimum cell voltage is 3.712mV or less then they perform cvli test and check to see if there is a cell that is equal to or less than "Cell Voltage Loss Judgement Value" whatever that may be, if one exists they replace the cell

Just found this:
Average cell voltage = “TOTAL BATTERY VOLTAGE” + 96 (im sure that should be divided by not +)

Cell voltage loss judgment value = Average cell voltage - (“MAXIMUM CELL VOLTAGE” - Average cell voltage) x 1.5

If cell voltage loss inspection has determined that a cell voltage is on the decrease (although not judged as a malfunction in the DTC), the module including this cell may need to be replaced.
 

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All of the Leaf factory manuals are online and available, I have no idea if they are copyrighted ... so don't shoot this messenger.

Here is one site - https://nicoclub.com/FSM/Leaf/2015 LEAF/

The battery test procedure is detailed within evb.pdf - it's a rather well written, informative and detailed description of all of the associated systems, including the test methodology.

I doubt anyone employed by Nissan to service or maintain EVs has ever read it.
 

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Discussion Starter · #9 ·
All of the Leaf factory manuals are online and available, I have no idea if they are copyrighted ... so don't shoot this messenger.

Here is one site - https://nicoclub.com/FSM/Leaf/2015 LEAF/

The battery test procedure is detailed within evb.pdf - it's a rather well written, informative and detailed description of all of the associated systems, including the test methodology.

I doubt anyone employed by Nissan to service or maintain EVs has ever read it.
Thats what I have been ploughing through all afternoon, it is informative !
 

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Discussion Starter · #10 ·
Thats what I have been ploughing through all afternoon, it is informative !
All of the Leaf factory manuals are online and available, I have no idea if they are copyrighted ... so don't shoot this messenger.

Here is one site - https://nicoclub.com/FSM/Leaf/2015 LEAF/

The battery test procedure is detailed within evb.pdf - it's a rather well written, informative and detailed description of all of the associated systems, including the test methodology.

I doubt anyone employed by Nissan to service or maintain EVs has ever read it.
Very true I printed out the relevant section and left it open on the passenger seat when it went for diagnostics with the initial test carried out no fault found when shown leaf spy screenie and asked to perform cvli test as per the printout 2 duff cells were reported
 

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Discussion Starter · #11 ·
Update so as previously mentioned I had a couple of weak cells in my battery, I took it to my local Nissan dealer ( Dumpton Park Nissan) where they performed a basic diagnostic test, the same one as they do with the annual health check.
This showed up no errors, and my battery was in good condition !!! so I then explained my problem and showed them Leaf Spy screenshots of my bad cells, I asked them to do a CVLI test which they did and hey ho 2 bad cells were reported.
The dealership had not come across this issue before and sought advice from Nissan Technical, they asked for further voltage readings.
Once these were submitted Nissan Technical said get it shipped to Lookers Nissan Gateshead for repair.
It was shipped off 2 days later and back in a week so a pretty damn good turnaround by Lookers.
2 modules were replaced and the difference in the performance of the battery is astounding to say the least !!

So from diagnosis to repair and return 10 days so I have to take my hat off to Nissan Customer services on this one, special thanks go to Dumpton Park Nissan for managing the repair and Lookers Nissan Gateshead for turning the car round quickly.

Great Service from Nissan !!
 

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Wow you managed a resolution from Nissan. Good to know

- Leaf 30 kWh
Sent from mobile phone so please mind the typos
 

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Out of interest, may I ask how weak was the bad cell? What was your delta reading?

If possible, scrub out your details (VIN etc) and post your Leafspy screenshot?
 

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Discussion Starter · #15 ·
122159


This is at 100% SOC

122160


This was when car said 0% charge as you can see lspy still reports 25%soc that 25% is the loss of range I experienced.
Lookers changed 2 modules one that contained cell 91-92 and 47-48.

I have noticed a big difference in the time it takes to charge the battery and the usable range has increased dramatically, I get at least 23 miles more usable range per charge, in a 24Kw that is a lot.
 

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Discussion Starter · #16 ·
122161


This is the firsrt time I charged to 100% after the cells were replaced, apparently the 4 blue cells will balance over the next few weeks of usage and reduce the mV delta to around 20mV, thats according to Lookers technician.
 

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View attachment 122161

This is the firsrt time I charged to 100% after the cells were replaced, apparently the 4 blue cells will balance over the next few weeks of usage and reduce the mV delta to around 20mV, thats according to Lookers technician.
I don't know why they do it like this. They should ideally replace cells are same voltage

- Leaf 30 kWh
Sent from mobile phone so please mind the typos
 

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Update so as previously mentioned I had a couple of weak cells in my battery, I took it to my local Nissan dealer ( Dumpton Park Nissan) where they performed a basic diagnostic test, the same one as they do with the annual health check.
This showed up no errors, and my battery was in good condition !!! so I then explained my problem and showed them Leaf Spy screenshots of my bad cells, I asked them to do a CVLI test which they did and hey ho 2 bad cells were reported.
The dealership had not come across this issue before and sought advice from Nissan Technical, they asked for further voltage readings.
Once these were submitted Nissan Technical said get it shipped to Lookers Nissan Gateshead for repair.
It was shipped off 2 days later and back in a week so a pretty damn good turnaround by Lookers.
2 modules were replaced and the difference in the performance of the battery is astounding to say the least !!

So from diagnosis to repair and return 10 days so I have to take my hat off to Nissan Customer services on this one, special thanks go to Dumpton Park Nissan for managing the repair and Lookers Nissan Gateshead for turning the car round quickly.

Great Service from Nissan !!
Brilliant. Most helpful. Thank you.
 

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Discussion Starter · #20 ·
I don't know why they do it like this. They should ideally replace cells are same voltage

- Leaf 30 kWh
Sent from mobile phone so please mind the typos
As it happens I do recall the local dealer telling me that Lookers had asked him to get the voltages of the cells on either side of the bad ones so that they could precharge the new cells before the car got to them in order to speed up the turnaround, so maybe it was the local dealer that didnt provide the correct voltages as requested.
 
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