2018 LEAF Poor Range / Battery Issue - Please Help

[gundamzd]

Hello everyone,
I'd like to share the range / battery issues with my 2018 LEAF here and see if anyone could give me some pointers. Thanks in advance!
I bought it on 4/8/2023, and I checked that the battery health bar was full. Later I installed LeafSpy and the SOH was at 91.1%.
However, my car only averages about 90 miles on a full charge (normal driving conditions), which falls far short of the estimated range of 136 miles. Also, the battery % drops really fast between 60% and 20%, losing 2% or more per mile. From 100% to 20% I only get about 60 miles. Then it gets back to normal again and I can drive another 30 miles from 20% to 0%.
When the battery is full, LeafSpy shows that there is a weak cell #15 that has 300+mv lower voltage than others. The voltage difference gets smaller as the battery drains.
When the car says the battery is dead and would not drive anymore, LeafSpy shows that there is still about 30% SOC left. I suspect that the weak cell tricked the car into thinking it has less charge than it actually does, causing it to prematurely shut down.
I took it to the dealer but they said there was no DTC about the cell voltage loss. I kept emphasizing that the range was really poor and the battery had a weak cell, but they told me it was "normal". There were some other codes but they fixed them by updating the controller. Now I finally have the car back after two weeks but the same issues persist.
Do you guys think the weak cell is the culprit behind these issues? Without actual DTCs Nissan would not replace it, so now I don't know what else I can do to get the range back. Any tips are greatly appreciated!

[LeftieBiker]

Welcome. Yes, it sounds very much like that bad cell is causing your issues, and yes, unfortunately Nissan won't do anything without a DTC. I just got up, but others will tell you how to deal with that. It should be possible, for example, to trigger one by accelerating hard up a steep hill. Normally one would do that at a low state of charge, but if yours has the highest voltage differential when full, I'd try that first. I'll be back later.

[Stanton]

When the battery is full, LeafSpy shows that there is a weak cell #15 that has 300+mv lower voltage than others. The voltage difference gets smaller as the battery drains.

Classic sign of a weak cell (and pretty bad at that). Unfortunately,you're going to have wait until it triggers some DTCs (as mentioned) unless you can find a sympathetic ear at Nissan. I've replaced a bad cell/module myself as Nissan doesn't like to do that sort of work (even if you pay them); they don't have a lot of (replacement) modules floating around, and it's a lot of time/labor.
Wish I could say it will be easy...but you have my sympathies.

[Learjet]

Yep, I went through that and Nissan wouldn't do anything until it logged a code.

Eventually, my car displayed a code and went into turtle mode, then Nissan replaced a module (group of cells) under warranty and now the car is good again.

[gundamzd]

Understood, thank you all for the reply!

[SageBrush]

When the battery is full, LeafSpy shows that there is a weak cell #15 that has 300+mv lower voltage than others. The voltage difference gets smaller as the battery drains.

Classic sign of a weak cell (and pretty bad at that).

Classic behavior to me is a widening voltage delta as the pack is discharged. Can you explain this pack's opposite behavior ?

[LeftieBiker]

I wonder it it's actually a defective BMS cell unit that's bleeding off too much charge when near full.

[Stanton]

When the battery is full, LeafSpy shows that there is a weak cell #15 that has 300+mv lower voltage than others. The voltage difference gets smaller as the battery drains.

Classic sign of a weak cell (and pretty bad at that).

Classic behavior to me is a widening voltage delta as the pack is discharged. Can you explain this pack's opposite behavior ?

Because that's the same thing mine did; even now (with new module), the voltage delta narrows as the pack empties...but returns to the same (slightly unbalanced) value it was when I installed it.
You are correct that the pack becomes more unbalanced (in general) as the SOC lowers, but we're talking here about an isolated module/cell that is "weak/bad" (never charges to the level of the rest of the pack).

[DaveinOlyWA]

Hello everyone,
I'd like to share the range / battery issues with my 2018 LEAF here and see if anyone could give me some pointers. Thanks in advance!
I bought it on 4/8/2023, and I checked that the battery health bar was full. Later I installed LeafSpy and the SOH was at 91.1%.
However, my car only averages about 90 miles on a full charge (normal driving conditions), which falls far short of the estimated range of 136 miles. Also, the battery % drops really fast between 60% and 20%, losing 2% or more per mile. From 100% to 20% I only get about 60 miles. Then it gets back to normal again and I can drive another 30 miles from 20% to 0%.
When the battery is full, LeafSpy shows that there is a weak cell #15 that has 300+mv lower voltage than others. The voltage difference gets smaller as the battery drains.
When the car says the battery is dead and would not drive anymore, LeafSpy shows that there is still about 30% SOC left. I suspect that the weak cell tricked the car into thinking it has less charge than it actually does, causing it to prematurely shut down.
I took it to the dealer but they said there was no DTC about the cell voltage loss. I kept emphasizing that the range was really poor and the battery had a weak cell, but they told me it was "normal". There were some other codes but they fixed them by updating the controller. Now I finally have the car back after two weeks but the same issues persist.
Do you guys think the weak cell is the culprit behind these issues? Without actual DTCs Nissan would not replace it, so now I don't know what else I can do to get the range back. Any tips are greatly appreciated!

Ok several moving parts here.

300 mV diff at high SOC indicates bad cell

Delta shrinking as SOC drops indicates bad battery connects (not uncommon)

Driving until shutdown is NEVER to be done. You are hastening your pack's demise.

Way to verify; When SOC starts dropping rapidly, let it drop 15-20%. Then park, shut down for a few mins, restart. If you gained more than 1% (you "shouldn't" gain anything with normal operation but systems do round) You have a weak cell.

This is hard to prove simply because codes are created but EASILY reset (a simple power cycle does it in most cases) leaving you w/o evidence.

A handful have been successful in getting the issue resolved by simply driving SOC down until the issue becomes very apparent then allowing the tech to take a test drive.

[Oostenrijker]

Hello everyone,
I'd like to share the range / battery issues with my 2018 LEAF here and see if anyone could give me some pointers. Thanks in advance!
I bought it on 4/8/2023, and I checked that the battery health bar was full. Later I installed LeafSpy and the SOH was at 91.1%.
However, my car only averages about 90 miles on a full charge (normal driving conditions), which falls far short of the estimated range of 136 miles. Also, the battery % drops really fast between 60% and 20%, losing 2% or more per mile. From 100% to 20% I only get about 60 miles. Then it gets back to normal again and I can drive another 30 miles from 20% to 0%.
When the battery is full, LeafSpy shows that there is a weak cell #15 that has 300+mv lower voltage than others. The voltage difference gets smaller as the battery drains.
When the car says the battery is dead and would not drive anymore, LeafSpy shows that there is still about 30% SOC left. I suspect that the weak cell tricked the car into thinking it has less charge than it actually does, causing it to prematurely shut down.
I took it to the dealer but they said there was no DTC about the cell voltage loss. I kept emphasizing that the range was really poor and the battery had a weak cell, but they told me it was "normal". There were some other codes but they fixed them by updating the controller. Now I finally have the car back after two weeks but the same issues persist.
Do you guys think the weak cell is the culprit behind these issues? Without actual DTCs Nissan would not replace it, so now I don't know what else I can do to get the range back. Any tips are greatly appreciated!

Ok several moving parts here.

300 mV diff at high SOC indicates bad cell

Delta shrinking as SOC drops indicates bad battery connects (not uncommon)

Driving until shutdown is NEVER to be done. You are hastening your pack's demise.

Way to verify; When SOC starts dropping rapidly, let it drop 15-20%. Then park, shut down for a few mins, restart. If you gained more than 1% (you "shouldn't" gain anything with normal operation but systems do round) You have a weak cell.

This is hard to prove simply because codes are created but EASILY reset (a simple power cycle does it in most cases) leaving you w/o evidence.

A handful have been successful in getting the issue resolved by simply driving SOC down until the issue becomes very apparent then allowing the tech to take a test drive.

Wow this verify my issue with weak cells: up to 20% Leafspy SoC, nothing very obvious is wrong. Then when I go down to 18% which is 8% dash SoC.

From that point, the dash SoC drops rapidly within mins or even seconds: almost like its counting down from 8% to 0% and on that point, I still have between 17% and 18% SoC left.

I easily still drove about 10km, got home and Leafspy reported at that point 15% SoC.



So when I arrived it was still showing ---% and after I got back into the car, to drive it to the charging station.

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It all of a sudden got back to showing 1% dash SoC. I only feel like, the dealership which is also the salesperson isn't taking me seriously. But they going do a battery test, when I bring it in for the recall.