The 62kWh Battery Topic

[OldManCan]

New SL+ saw 775 first time I charged to 100% and last time it was 772 after about 3500 miles and 2 months of use. I take 775 to be the 100% for my battery.

 

[Learjet]

First positive adjustment I have witnessed....only .02% :roll:

Weak cell, basically no change in voltage difference. I have noticed some erratic battery percentage movements between 27 and 31% on the car display. Sometimes it will drop rapidly from 31 to 27%...then might increase a little later. Below 27% it is normal again as the battery reduces.

 

[Learjet]

Ok...took the car to "-- on the Battery" then ran the heater on high with windows open until turtle, then finally battery disconnect....here are the results and problems....

fully charge only got 156 miles until "-- battery %" readings below:

Then turtle mode after about an hour with heater on high and windows open:

When it hit turtle mode above...it didn't take long after for the battery to disconnect!!

So....is this warranty? will find out when I try to get the annual battery check next month.

Should I hold out as long as I can until I get a DTC...then maybe a new pack under warranty?

Comments or suggestions? The reduced range thing is a small problem...but not a deal killer right now.

 

[LeftieBiker]

You definitely have a bad cell, and I think that a CVLI test will indicate that, but I can't say for sure. I don't think we've ever seen the exact parameters for the test, and required results to get a new cell or battery.

 

[SageBrush]

Cell #1 is weak.
As Lefty says though, Nissan *appears* to ignore weak cells when the warranty is called upon unless a related DTC is logged.

I *think* that a DTC can be triggered by stomping on the go pedal until the LEAF complains when the SoC is relatively high. A cold battery should be your friend in this endeavor.

 

[GerryAZ]

If range is not an issue for you, I would just keep driving the car unless or until it indicates EV System error codes. You could also mention low range to your dealer to document your concerns. Don't mention LEAF Spy reading but ask if there are any tests they could perform. I would also be absolutely certain to get annual battery tests performed on time. Be aware that it may go into Turtle mode suddenly without much warning when that weakest cell drops to the threshold.

 

[SageBrush]

Be aware that it may go into Turtle mode suddenly without much warning when that weakest cell drops to the threshold.

If that happens, log a safety incident with Nissan AND with the NHTSA. Nissan is playing loose with people's safety and it is way past time for Nissan to act responsibly.

 

[Learjet]

all good information...thanks!!!

 

[knightmb]

I have to agree with all the others, it looks like someone dropped Cell #1 on the concrete floor when the battery was being put together at the plant :? , the rest of the cells look fine. I suppose there is the really off chance that it just needs to be cycled a few more times to bring it up with it's siblings, but that voltage difference compared to the others is just too far out there. I've never seen one that far off, the most I've seen on any of the ones I've worked with was probably +250 mV max. I wonder if that is affecting the SOH calculations as well.
Seems like you have a silver lining though, you can drive your Leaf as normally as you can, keeping in mind that when the SOC gets low, be careful of the sudden turtle and then disconnect mode due to the weak cell. But, it seems you could be able to generate a DTC code easily given the right conditions and basically get a free replacement pack under warranty, that part is like getting a brand new Leaf again. :mrgreen:

 

[LeftieBiker]

I should caution that Nissan is still only obligated, AFAIK, to replace the bad cell, not the whole pack. They usually replace the whole pack, but not always. If the #1 cell is easily accessible, they may opt to just replace that one...

 

[OldManCan]

At what point do we call it a bad cell? I did my first full discharge / charge exercise couple weeks ago and found that one of my cell shows 105mV delta at lowest SOC. I’m hoping after some time of reconditioning it will sort itself up and I’m not worried but just wanted to know where you would declare it a bad cell. Thanks

 

[LeftieBiker]

I don't think we have a number, but when it's far below the other cells at a high SOC, I'd say that that's a bright red flag. If it's near the bottom of the histogram while the others are near the top, I'm going to call that a bad cell, because they can't recover that much. If I had to pick a number, I'd say 150+ mv at a high SOC, like 80% or above. It's more a gray area at a low SOC, but 200+mv at a SOC of 20% or less should mean, at the very least, a seriously weak cell...

 

[OldManCan]

Thanks for that input. I am usually at low 10s with usable SOC ranges. I will observe this particular cell next time I do a 0% deplete to 100% charge exercise and see if it improves along the way.

 

[knightmb]

I should caution that Nissan is still only obligated, AFAIK, to replace the bad cell, not the whole pack. They usually replace the whole pack, but not always. If the #1 cell is easily accessible, they may opt to just replace that one...

That's true, I suspect though it's probably cheaper to have the dealership do the pack replacement (labor hours wise) than to bring in a certified Leaf tech to the dealership and then spend all day taking the pack apart to replace, test, verify, certify, etc. If the dealership can just unbolt and reconnect some plugs, pair up the pack and send the old one back to Nissan. They (Nissan) probably have a better facility to examine the pack and determine why the single cell went bad and recycle the rest of them into some other machines that can use the batteries. A one-off like this could be more interest to them than if *all* the packs had a bad Cell #1, then they would know something was up at the battery plant. :shock:

 

[Learjet]

Re-Charged fully overnight...you can see fully charged, no change, the cell is ~107 mV lower....the problem is at the lower SOC levels.

 

[LeftieBiker]

If I had to guess, I'd say that with no DTC, Nissan won't act on it. It will have to get worse. I'm also thinking that if they did act, it would be to replace that one cell module.

 

[knightmb]

Still showing 54.2 kWh of capacity also, which is still good given the lower SOH, I would imagine that if Cell #1 was behaving properly, you could easily get it back up into the +56 kWh range of capacity for a full charge. As the others have said, it will take some tricky work to get it to DTC on that cell (safely so you don't lose power down the middle of the highway in traffic for example), but as always we find a way here... :lol:

 

[Learjet]

Still showing 54.2 kWh of capacity also, which is still good given the lower SOH, I would imagine that if Cell #1 was behaving properly, you could easily get it back up into the +56 kWh range of capacity for a full charge. As the others have said, it will take some tricky work to get it to DTC on that cell (safely so you don't lose power down the middle of the highway in traffic for example), but as always we find a way here... :lol:

What has me worried is the lost of range and the quick turtle mode.

Last year I tried for my first battery check on the 1st year anniversary...called all the dealers in my area and none could or would do it. Made notes of that for future reference and put it off because of Covid. This year I will make it happen and call Nissan HQ if needed. I'll report back after the battery health check.

 

[SageBrush]

Still showing 54.2 kWh of capacity also, which is still good given the lower SOH, I would imagine that if Cell #1 was behaving properly, you could easily get it back up into the +56 kWh range of capacity for a full charge.

It doesn't work that way. At high SoC the available pack voltage has only dropped 100 mV.
At low SoC, all the good cells are unable to discharge to the normal threshold for low cell voltage because the bad cell has invoked turtle mode. The tell tale sign of a pack with a weak cell is normal range estimate at high SoC, but in practice that range is not close to realistic even with EPA type driving


To my knowledge, Nissan has never disclosed the conditions that set a DTC when weak cell(s) are present, although past threads make it clear that Nissan has no interest in having the warranty invoked when an old pack has multiple weak cells. In this case ONE cell is weak, which is presumably what the algorithm is looking for. The greater the discrepancy between one weak cell and the average of the rest of the pack, the more aberrant the pack. This is why stomping on the go pedal when the pack is cold will likely unmask the weak cell, and perhaps cross the threshold to set a DTC

 

[Learjet]

Still showing 54.2 kWh of capacity also, which is still good given the lower SOH, I would imagine that if Cell #1 was behaving properly, you could easily get it back up into the +56 kWh range of capacity for a full charge.

It doesn't work that way. At high SoC the available pack voltage has only dropped 100 mV.
At low SoC, all the good cells are unable to discharge to the normal threshold for low cell voltage because the bad cell has invoked turtle mode. The tell tale sign of a pack with a weak cell is normal range estimate at high SoC, but in practice that range is not close to realistic even with EPA type driving


To my knowledge, Nissan has never disclosed the conditions that set a DTC when weak cell(s) are present, although past threads make it clear that Nissan has no interest in having the warranty invoked when an old pack has multiple weak cells. In this case ONE cell is weak, which is presumably what the algorithm is looking for. The greater the discrepancy between one weak cell and the average of the rest of the pack, the more aberrant the pack. This is why stomping on the go pedal when the pack is cold will likely unmask the weak cell, and perhaps cross the threshold to set a DTC

Multiple full accelerations this am...but not really cold...no DTC.

You are spot on with the range...show 209-218 fully charged...but normal mixed driving...less than 160 miles actual right now. Really drops around 30% at an alarming rate.