New Leaf 2016 SL, Bad Battery?

[gregn]

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[Cryptizard]

You should have the tech at the dealer take the car out and run it from 100% down to turtle so they can see for themselves that getting only 50 miles isn't normal.

They did do that. They said mileage varies according to temperature and speed blah blah blah no particular distance is guaranteed. If there isn't a check engine light on they can't do anything. That is what they said.

 

[Jedlacks]

You should have the tech at the dealer take the car out and run it from 100% down to turtle so they can see for themselves that getting only 50 miles isn't normal.

They did do that. They said mileage varies according to temperature and speed blah blah blah no particular distance is guaranteed. If there isn't a check engine light on they can't do anything. That is what they said.

If you were in or around Atlanta I would ask you to pick me up to go for a ride. If I "exercise" my wife's ICE mercedes it can give me 6-8 mpg. Getting 50 miles out of a new car would seem strange while reading it on the board.

 

[Foschas]

There is clearly a bad cell.

I initiated a lemon law demand on a Toyota Prius because the car was not drivable and "waiting parts" for weeks. No drama just a concise, polite written descriptive of the problem and time lines. Low and behold the part magically appeared with personal and written corporate apologies and a gift card.

https://www.consumeraffairs.com/lemon_law/demand_letter.html

Nissan North America Inc.
Jose Munoz
One Nissan Way
Franklin, TN 37067
Phone: (615) 725-1000

 

[sendler2112]

Did you show the tech specialist the screen shot of the cell that is constantly 100mv below the others? Don't give up. Post another screen shot after letting the car sit on charge for as long as you can get by without using it to try to balance the pack. Maybe even try disconnecting the charger and restrting the charge a couple times after it is full to get it all the way to 100% repeatedly to give it the best chance to balance the weak cell. Packs are charged with all of the cells in series all at once and the only way the lowest cells can catch up is when the higher cells go "red" which indicates their shunt resistors are switched on to bleed power away from them while the lower cells are still soaking up power. But this can't happen if the car keeps thinking it is full enough and discontinuing the charge.
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If it is still low it is not a big deal or even that expensive for Nissan to replace one cell group for you if that is all it is. You need to document repeated screen shots over time to show it is not going away.

 

[sendler2112]

Actually, you have 29 L2 charges now and I would assume most of those were to 100% so if it didn't balance by now , it never will. Print out a few more leafspy screen shots at 100% and a couple at less than 20% when you get home which will probably look even worse. Call Nissan and open an owner contact and make another appointment at the selling dealer to show all of this to them. More than 100 millivolt imbalance, always on the same cell group is an obvious fault. Which could probably be fixed just by replacing the one cell group which wouldn't even cost them that much.
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Your overall capacity is being limited by the weakest cell. When that one hits the low voltage cut off voltage, you are done. Even if all of the other cells have plenty of energy left.

 

[Cryptizard]

Did you show the tech specialist the screen shot of the cell that is constantly 100mv below the others? Don't give up. Post another screen shot after letting the car sit on charge for as long as you can get by without using it to try to balance the pack. Maybe even try disconnecting the charger and restrting the charge a couple times after it is full to get it all the way to 100% repeatedly to give it the best chance to balance the weak cell. Packs are charged with all of the cells in series all at once and the only way the lowest cells can catch up is when the higher cells go "red" which indicates their shunt resistors are switched on to bleed power away from them while the lower cells are still soaking up power. But this can't happen if the car keeps thinking it is full enough and discontinuing the charge.
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If it is still low it is not a big deal or even that expensive for Nissan to replace one cell group for you if that is all it is. You need to document repeated screen shots over time to show it is not going away.

Yeah I showed them the screen shots. They say no check engine light so nothing is wrong. And this is the Nissan specialist btw not the dealer techs. All of the cells but the weak ones are constantly being bled (I check all the time in leafspy), it doesn't balance it at all. There is no where else to escalate it, I have talked to Nissan headquarters and they just say if there is no check engine light then nothing is wrong with it and they won't fix anything :-\ Very frustrating.

 

[Cryptizard]

Actually, you have 29 L2 charges now and I would assume most of those were to 100% so if it didn't balance by now , it never will. Print out a few more leafspy screen shots at 100% and a couple at less than 20% when you get home which will probably look even worse. Call Nissan and open an owner contact and make another appointment at the selling dealer to show all of this to them. More than 100 millivolt imbalance, always on the same cell group is an obvious fault. Which could probably be fixed just by replacing the one cell group which wouldn't even cost them that much.
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Your overall capacity is being limited by the weakest cell. When that one hits the low voltage cut off voltage, you are done. Even if all of the other cells have plenty of energy left.

Yes this is what I suspect, and have suspected for months now. I have taken many screenshots and shown them to the dealership and the Nissan technical specialist. I have called Nissan headquarters and the response every time from everyone I talk to is that there is no check engine light so there is nothing wrong with it and they will not do any repairs.

 

[sendler2112]

You have plenty of time. I guess you will just have to get by as best as possible for now and then hammer them again when you get closer to three years. If it makes it that far.

 

[Cryptizard]

You have plenty of time. I guess you will just have to get by as best as possible for now and then hammer them again when you get closer to three years. If it makes it that far.

So the most recent time I took it in to the dealer, they were able to observe a 240 mV differential between the functioning cells and the weak one but they (the dealer and the Nissan corporate specialist) insist that this is not outside of allowable tolerances. From everything I have read on this forum it seems like over 100 mV is a lot, so I don't know what to do at this point.

 

[sendler2112]

Don't let it drive you crazy. The car still does what you need it to do and you have plenty of time left in all of the warranties. Did you lease or buy? Do you like the car if it wasn't having this problem?
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240mv is a huge difference. The 100mv that you have shown at the top of the charge is a huge difference. It is obviously taking 14% right out of your pack already because the low voltage cutoff is being calculated from the bad cell. Too bad they won't just cough up and replace the couple cell groups that keep looking week and get it over with. They are wasting more manpower on just testing it over and over again ever time you bring it in to tell you it is ok. Have you ever been invited into the shop to look at the screens that their diagnostic equipment can see? I wonder if it even shows them the individual cell voltages that Leafspy does. It seems that eventually the mil light will be triggered. If you really want to capture a screenshot of that cell at it worst you can sometime when it is convenient, and you have time to do a full recharge on the car before you need it again, find a little hill or clear piece of road near your house on your way home some night when the battery is already low so you don't have to waste alot of time, and do some high power accel runs to stress the bad cell and get the biggest voltage differential possible at the bottom of the state of charge. Pop the car into neutral and stop with the friction brakes to keep it from regenning. Do it again and again as long as it takes to get it down as far as you dare, watching your Leafspy and your temp gauge but beware that it may go from LBW to VLBW to turtle in a very short time because the car will be just mainly looking at the weak cell at that point. So make sure you are close to home. Running your car down to turtle shouldn't even stress out the rest of the battery at this point since it will just be the one cell that is turtled.
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Post all of your screenshots here and email links to this thread every time you update this to the service manager and to Nissan corporate and eventually they will realize they should fix it for you because it is obviously faulty and I don't believe they will even need to replace the whole pack. The cell groups should be individually serviceable in the shop.

 

[DaveinOlyWA]

240 mV is a huge difference but its all relative. I know someone in their 24 kwh LEAF who went to turtle with SOC of nearly 14%! but this LEAF is cycled shallowly, rarely top end balanced, etc. But went to Turtle because one cell (that is all it takes) was way out of balance. Now will this happen every time? No because cells that far out of balance tend to naturally bring themselves back into the pack over time. Now is it always a possibility that cell is simply an indication of pack failure just around the corner but in this case, only the single module needs to be replaced, not the entire pack.

problem with that is the pack is not designed to be broken open. Its sealed up pretty tight and its very labor intensive to open it. Its not a simple matter of loosening a dozen bolts. So even a single module is going to be expensive.


one way to combat a low cell is ratchet your SOC up higher. Weak cells are more pronounced as the pack is depleted. Also charging to 100% several days in a row could help the cell become more balanced with the pack

 

[sendler2112]

one way to combat a low cell is ratchet your SOC up higher. Weak cells are more pronounced as the pack is depleted. Also charging to 100% several days in a row could help the cell become more balanced with the pack

He is way past this point. This pack has been charged 50 times now and that cell just keep getting worse out of balance.The rest of the pack reaches the end of charge before that cell can balance. And even if it were manually balanced at the BMS pins with a hobby charger it would immediately go right back out of balance on the first deep cycle since it has less capacity than the other cells and a higher internal impedance which prevents it from accepting charge current as fast as the others. It is obviously defective from day one. Just not well matched to the rest.
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It doesn't require a whole new pack. Just a couple new cell modules (there is one more that is suspect in the screen shots) would make this whole situation right. Which can be done in an afternoon. Right in the shop.
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Running the car to turtle under max accel a couple times might get the mil light to come on if the imbalance gets large enough. Charge back up to 10% and go do it again, and again. To get those two cells as far out of balance as possible. It won't hurt the other cells because they will still be at 20% when the bad one hits 0%.

 

[drhlee1]

Any chance you can find another Leaf near by (friends, co-worker or someone here on MNL) to drive the same routine side by side? Both cars would start off with 100% SOC. This way you would have the same outside temperature and traffic conditions. The driving style of each may be different but it should be within a few percent. At the end of the trip, you would have SOC of a normal Leaf vs yours. You can then show Nissan your new finding. If Nissan still won't respond, you can file complaints to lemon law or BBB.

 

[Cryptizard]

Don't let it drive you crazy. The car still does what you need it to do and you have plenty of time left in all of the warranties.

Actually it doesn't. My round trip commute is 60 miles and it currently only gets about 50-55 miles on a charge. I am driving my wife's car or using the DC fast charger, which I try to avoid because it is terrible on the battery. I might try to run it very low a few times in a row and see if that gets a light to come on.

 

[Cryptizard]

Any chance you can find another Leaf near by (friends, co-worker or someone here on MNL) to drive the same routine side by side? Both cars would start off with 100% SOC. This way you would have the same outside temperature and traffic conditions. The driving style of each may be different but it should be within a few percent. At the end of the trip, you would have SOC of a normal Leaf vs yours. You can then show Nissan your new finding. If Nissan still won't respond, you can file complaints to lemon law or BBB.

At one point I was given a Leaf as a loaner car while mine was in the shop so I know that a normal car gets better mileage. They gave me a 24 kWh Leaf and it went about 5 miles further on a charge than my 30 kWh version. Nissan responds to that by saying that no mileage is guaranteed and range will vary from car to car... they are basically doubling down on the fact that there is no check engine light on so therefore there cannot be anything wrong with the car. I tell them, not being able to find out what is wrong with the car is not the same as there being nothing wrong with the car but they don't understand the distinction.

I am pursuing the lemon law option but it is hard to find a lawyer that is willing to try to understand all the intricacies of electric cars. They basically ask, "did the dealer admit that something was wrong?" and when I say no they won't take the case. As far as the BBB, my dealer already has an F rating and they don't respond to complaints :-(

 

[sendler2112]

Actually, if you like the car, you are in a good position. Just enjoy it as as if nothing is wrong. You may get several years out of this battery before it eventually sets the mil light on. Which I believe you can probably do at any time by never charging to 100% to allow any balancing of the cells and by taking the state of charge to a hard turtle whenever it is low and yo are close to home. Then when they are forced to make a repair, maybe you will get a new complete battery.

 

[LeafMuranoDriver]

Don't let it drive you crazy. The car still does what you need it to do and you have plenty of time left in all of the warranties.

Actually it doesn't. My round trip commute is 60 miles and it currently only gets about 50-55 miles on a charge. I am driving my wife's car or using the DC fast charger, which I try to avoid because it is terrible on the battery. I might try to run it very low a few times in a row and see if that gets a light to come on.

Don't take the bold part so seriously. It's not that bad on the battery and can actually improve the battery in the short term. I try to QC as often as possible.

Last week my Ahr was down to 54.04. After driving a lot for a week and QC'ing almost every day, I'm up to 57.5 Ahr.

Maybe a few QC's will be good for your battery. How many have you done?

 

[DaveEV]

It's not that bad on the battery and can actually improve the battery in the short term. I try to QC as often as possible.

QCing will always speed up actual capacity loss. But I wouldn't avoid it if you need it, either.

Just because the car thinks the battery holds more capacity after quick charging, doesn't mean that it actually does. The car can only estimate capacity and for some reason, QCing makes the car think the battery improves capacity.

QCing heats up the pack significantly and heat speeds up the rate of capacity loss.

 

[DaveinOlyWA]

Some LEAFs were tested using various types of charging and the QC LEAFs did degrade faster but it was not "significant" according to them (they failed to define what significant meant) but I read the report and feel that the reason for the degradation was more likely heat and not the type of charging.

So fast charge all you want but keep it no higher than 6-7 bars and you will be fine.