HV Battery Trouble

[RNeil]

My 2021 Leaf SV with a 40 kwh battery usually works well around town. But once or twice a week, I need to go to the other side of town. It is 28 miles one way or 56 miles round trip.

I start with 100% charge. The car has been in the garage overnight at a temperature of about 60F. I drive 28 miles, mostly highway. The dash display might show 75% charge and 110 miles range. The car sits for maybe 3 hours at a temperature of maybe 30F. As I drive home, the charge goes below 50% and then drops very fast. On two occasions, I have gotten the low battery warning. I find that the charge can go up if I slow down. The last such trip I took, I used the cruise control and set it for 65 or 70 mph. I reduced it to 60 mph when I was worried about the range. I got the low battery warning, which cleared when I got off the highway.

LeafSpy shows a SOH of 90.08%. It shows SOC of 49.3% when the dash display shows 10% (up from 5%). It showed a voltage deviation of 123 mV and identified 7 weak cells. After charging it showed a deviation of 3 mV.

I'm the original owner. The car has 28,000 miles on it. LeafSpy counts 15 quick charges. I did not expect this trouble on a relatively new car.

Any suggestions?

 

[NeguE]

I'm sorry for your situation.
You better show us print screens with LeafSpy cells page to understand better your situation.
A battery At 0*C or 30F ( from my experience ) you have half of energy and half of continuous discharge power.
Try to use when battery have at least 15*C or 45F for better performance. Charge before drive.

 

[RNeil]

I'm just learning how to take a screen shot. But LeafSpy still has the data. Tomorrow I will make a 40 mile round trip without the 3 hour wait in the middle.

I also just found how to get the capacity bars on the dash display. It shows a solid grey bar. I don't know if that means it has all the bars or none of them. Neither interpretation makes sense. I have a January 2 appointment at the Nissan dealer.

 

[Lucky]

I'm just learning how to take a screen shot. But LeafSpy still has the data. Tomorrow I will make a 40 mile round trip without the 3 hour wait in the middle.

I also just found how to get the capacity bars on the dash display. It shows a solid grey bar. I don't know if that means it has all the bars or none of them. Neither interpretation makes sense. I have a January 2 appointment at the Nissan dealer.
View attachment 6240

Was this taken when the car was idle? I doubt and hope not because it doesn't look good at all. When your cells are balanced when charged and this much unbalance @50% SOC it can mean a big capacity mismatch. The BMS must protect the weakest cell so it reduces ouput power. The dealer should look into this but they avoid it at all cost. Wish you luck.

 

[RNeil]

The car was idle after the trip.
Today I dropped off my nephew at the airport. I traveled 42 miles in 50 minutes at speeds of up to 75 mph. I recorded LeafSpy screens before and after. Both were with the car parked. I started with 100% charge. At the airport, it showed 80%. On the way home, it got down to 10% and I briefly saw the low battery warning. When I got home it was 40%. The battery temperature started and ended at about 60F. The outside temperature was 37F.

 

[Stanton]

It's already been said, but you obviously have some weak cells; low temps tend to exacerbate the problem.
The real problem is the cells span across multiple modules (which is the smallest "replaceable" element). I've been there done that (with a 40 kWh pack), so I looked up exactly how many modules you are talking about:

• cell #17 -> module #5
• cells #21-24 -> module #6
• cell #75 -> module #19
• cells #83-84 -> module #21
• cell #85 -> module #22
• cell #95 -> module #24

These span a combination of the rear and front module stacks (mine was only in the rear stack), which means more labor to assemble/disassemble. You could save a few $ by only replacing the worst offenders (or the ones with multiple bad cells), but the truth is the others will just get worse and labor is a big piece of the cost (if you have to do it again). I have to say: the number of modules is high enough that it might even warrant a new pack (if done under warranty).
Wish I had better news; good luck with whatever you do.

 

[RNeil]

I just got a call from the stealership. She says they checked the car and it's fine. I said but it's not working right. She says they will do a diagnostic, but if it's not covered under warranty, it will cost $180.

 

[hornstudio]

There are dozens of threads across the globe now in countries like Spain, France, Germany, Norway, etc. with single cell failures making 40kWh Nissan partially un-drivable.
Law division of Nissan is in panic mode. Hundreds of thousands of 40kwh batteries have to be upgraded for free by Nissan. At least a software update for the BMS has to be invented that excludes dead cells.

 

[RNeil]

Good news! A technician that knows something about EVs (they only have one) looked at it and recognized that something is wrong that needs to be fixed under warranty. First they said I might need a new battery, for which I might have to wait weeks or months, then they said they are waiting for instructions from Nissan.

Meanwhile, I am driving a loaner. It is a 2024 Leaf SV+. The big difference between it and my car is the 62 kwh battery rather than the 40 kwh battery.

 

[Turbo21]

Good news! A technician that knows something about EVs (they only have one) looked at it and recognized that something is wrong that needs to be fixed under warranty. First they said I might need a new battery, for which I might have to wait weeks or months, then they said they are waiting for instructions from Nissan.

Meanwhile, I am driving a loaner. It is a 2024 Leaf SV+. The big difference between it and my car is the 62 kwh battery rather than the 40 kwh battery.

great news , driving and wearing out their battery and tyres on a loaner is a bonus every day you have it. I would visit the dealership and attach a 12v solar panel to my car direct to the battery, that is the only casualty i can think of in this situation else id never follow up the dealership and just keep driving the loaner. Take photos of your car from every angle so you can prove dents and scratches occuring during the long wait and ask what the excess is on the loaner insurance policy.

 

[NeguE]

View attachment 6244View attachment 6245

I see that you charged mainly AC.
You charged mainly at 100% overnight ?
Did you QC in a ~500+ miles ride summer time ?

I have a 30kwh and I cooked 2 cells because I QC 3 times in 3 h , summer temps (40*C) and i hit red temp indicator in last charge.

 

[RNeil]

Yes I usually connect the charger in my garage and disconnect it when it is finished. I only used it for 3 long trips. They were in warmer weather, used the highway and level 3 charging. I now take my ICE car on long trips.

 

[nlspace]

At least a software update for the BMS has to be invented that excludes dead cells.

Huh? How could you exclude any cell in a series string?

 

[RNeil]

It has been 3 weeks. I picked up my car yesterday. It behaved well on the ride home, except the charge port door opened on the highway because it was not properly latched. This morning I got this from LeafSpy as it was parked. I am happy. It is interesting to note that although it is a new battery, the number of charges was not reset.