The 62kWh Battery Topic

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I suppose this is a bit tongue in cheek but I realise I didn't have any worries about SOH or even knew what it meant before I bought a Leaf Spy dongle. I think my best plan is to chuck the dongle in the draw, forget about it and just enjoy the car.
 
oxothuk said:
Doesn't sound abnormal.

I bought my 62kWh Leaf in May 2021 and it is down to 92.7%. Decline was rapid for first 9 months, but has slowed dramatically since then. Batteries degrade with age, even if you don't drive much.
Sounds like your car was sitting around before being bought. When was the build date?
 
That is not a hot climate, so the 9% degradation in ~ 2 years is more than I expect.

Look for more shade
DO NOT park the car in a poorly ventilated, hot garage
Keep on LeafSpy monitoring once a year. Perhaps the first year was worse than now.
 
Had my first positive SOH adjustment....still dealing with the weak cell....


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I've got an odd problem. My 22 Leaf SV+ has one weak cell. At full charge it is 70-75mv lower than the other cells. As I deplete the battery, the gap narrows. At 20% or less charge it is only 25mv low compared to the other cells. I've taken the battery down as low as 6-8% and then recharged it overnight. The cell sill persists in being lower by 70-75mv compared to the rest of the pack. I've done this more than a few times but but I can't get the cell to equalize. SOH is 97.93%, AH = 172.75. Has anyone else seen anything similar?
 
SageBrush said:
That is not a hot climate, so the 9% degradation in ~ 2 years is more than I expect.

Look for more shade
DO NOT park the car in a poorly ventilated, hot garage
Keep on LeafSpy monitoring once a year. Perhaps the first year was worse than now.

What is 'hot' for the battery? What is the max temperature in a garage before the battery suffers. July and August are hot months in the South of France.
 
What is Hot for the battery actually depends on another factor: whether or not the temperature drops enough at night to let the battery cool. 30C isn't really bad as a daytime high - unless the temperature stays in the twenties at night. A desert environment where it gets to 36 in the daytime but then drops well below 20 at night could actually be easier on the battery, as long as it gets exposed to the cool nighttime air.
 
johnlocke said:
I've got an odd problem. My 22 Leaf SV+ has one weak cell. At full charge it is 70-75mv lower than the other cells. As I deplete the battery, the gap narrows. At 20% or less charge it is only 25mv low compared to the other cells. I've taken the battery down as low as 6-8% and then recharged it overnight. The cell sill persists in being lower by 70-75mv compared to the rest of the pack. I've done this more than a few times but but I can't get the cell to equalize. SOH is 97.93%, AH = 172.75. Has anyone else seen anything similar?

see my post before yours and read back in this thread...I have the same problem with a weak cell.
 
Duggo1941 said:
SageBrush said:
That is not a hot climate, so the 9% degradation in ~ 2 years is more than I expect.

Look for more shade
DO NOT park the car in a poorly ventilated, hot garage
Keep on LeafSpy monitoring once a year. Perhaps the first year was worse than now.

What is 'hot' for the battery? What is the max temperature in a garage before the battery suffers. July and August are hot months in the South of France.
There is not a line in the sand -- higher is worse. The relation between temperature and degradation is logarithmic, insofar as it represents a chemical reaction. See Arrhenius' law of reaction rates for details.

My rule of thumb is that 6 temp bars is not great and 7 temp bars is going to be noticed by the owner as accelerated degradation if it is more than infrequent. In any case, it is not the ambient temperature, it is the pack temperature. The other important thing to note about temperature is that the duration of the temperature matters a lot more than the temperature per se. 85F for 10 hours is a lot worse than 90F for one hour. This is mostly why it is a bad idea to put a hot pack in a poorly ventilated, hot garage. That just extends the time the pack sits at high temperature.

If your garage in the early morning (say 6am) is within a couple degrees or warmer than outside, park outside.
 
Learjet said:
johnlocke said:
I've got an odd problem. My 22 Leaf SV+ has one weak cell. At full charge it is 70-75mv lower than the other cells. As I deplete the battery, the gap narrows. At 20% or less charge it is only 25mv low compared to the other cells. I've taken the battery down as low as 6-8% and then recharged it overnight. The cell sill persists in being lower by 70-75mv compared to the rest of the pack. I've done this more than a few times but but I can't get the cell to equalize. SOH is 97.93%, AH = 172.75. Has anyone else seen anything similar?

see my post before yours and read back in this thread...I have the same problem with a weak cell.
In my case the real oddity is that the cell seems to improve as the battery discharges. 25mv at a low state of charge isn't much of a difference and I wouldn't expect it to cause any real problem. I just keep wondering why it doesn't charge back up properly.
 
johnlocke said:
In my case the real oddity is that the cell seems to improve as the battery discharges. 25mv at a low state of charge isn't much of a difference and I wouldn't expect it to cause any real problem. I just keep wondering why it doesn't charge back up properly.

That is a new one for me. I agree though, probably much less a concern than the typical case of the mv delta growing as the SoC drops
 
johnlocke said:
Learjet said:
johnlocke said:
I've got an odd problem. My 22 Leaf SV+ has one weak cell. At full charge it is 70-75mv lower than the other cells. As I deplete the battery, the gap narrows. At 20% or less charge it is only 25mv low compared to the other cells. I've taken the battery down as low as 6-8% and then recharged it overnight. The cell sill persists in being lower by 70-75mv compared to the rest of the pack. I've done this more than a few times but but I can't get the cell to equalize. SOH is 97.93%, AH = 172.75. Has anyone else seen anything similar?

see my post before yours and read back in this thread...I have the same problem with a weak cell.
In my case the real oddity is that the cell seems to improve as the battery discharges. 25mv at a low state of charge isn't much of a difference and I wouldn't expect it to cause any real problem. I just keep wondering why it doesn't charge back up properly.
I had 25 to 30 mV delta at full charge when my 2019 SL+ was new with less delta when discharged. The delta at full charge is typically less than 10 mV now after more than 48,000 miles of use. I was initially a little concerned, but chose not to fret over it since it came with an 8-year, 100,000-mile warranty. Although the capacity has dropped a little, the battery pack is very well balanced now. Therefore, I would not worry about the unbalance you see--just drive/charge the car and enjoy it.
 
To add; my Plus had 2 cells with a 210% greater delta than the rest of the pack at (a VERY) full charge when picked up from the dealer. Delta was 32 mV so, well not really concerned as that is a minor thing at high SOC.

I did notice the delta being as low as 15 mV as SOC traveled downward. Fast forward 35,000 miles and I don't do many full charges but the last one had a delta of 24 mV but the one previous had one at 17 mV. Both still significantly higher than previous packs but I ventured into the "very low" and had no issues including the end of the weekend the full charge initiated with a 10 mile 70 mph drive to the charger with nothing on the dash (zero SOC, zero GOM) and had no power issues.

My first suspect in all cases like this is Nissan instrumentation.
 
It is time to post results of the latest discharge test for my 2019 SL Plus. The last 90-day adjustment (between April 9th and 12th) yielded a loss of 1.36 AHr and 0.77% SOH. The car still has 90.4% of original battery storage capacity (based upon charging energy from the wall) after 48,125 miles and 33 months of use. Ahr is still 89.6% of reading after first full charge. Gids are still 89.9% of reading after first full charge. Discharge tests are performed every 3 months by driving the car until battery is deeply discharged and then running HVAC in the driveway until shutdown (main DC contactor opens). The car is then charged fully using AeroVironment 240-volt, 30-ampere L2 EVSE. Charging energy is measured by a revenue accuracy digital meter on the 240-volt input to the EVSE.
LEAF 2019 Battery Information 7.jpg
 
The car still has 90.4% of original battery storage capacity (based upon charging energy from the wall) after 48,125 miles and 33 months of use.

Thanks for the in-depth assessment of the car's battery Gerry. One number I would like to see if what SOH LeafSpy shows when your (better) analysis is showing 90.4%? Is it the same, less, more? Thanks!
 
dmacarthur said:
The car still has 90.4% of original battery storage capacity (based upon charging energy from the wall) after 48,125 miles and 33 months of use.

Thanks for the in-depth assessment of the car's battery Gerry. One number I would like to see if what SOH LeafSpy shows when your (better) analysis is showing 90.4%? Is it the same, less, more? Thanks!
The SOH as read by LEAF Spy was 99.29% when the car was new and 88.92% at the last discharge test. Therefore, the SOH is about 89.6% of original. In general, LEAF Spy numbers show slightly worse deterioration than charging energy from the wall, but difference is minimal.
 
The SOH as read by Leaf Spy was 99.29% when the car was new and 88.92% at the last discharge test. Therefore, the SOH is about 89.6% of original. In general, LEAF Spy numbers show slightly worse deterioration than charging energy from the wall, but difference is minimal.

Thanks, I think we can live with that tiny variation between LeafSpy and observed actuals!
 
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