Battery percentage drops erratically on acceleration

[cellocolin]

My 2018 Nissan Leaf SL (40KW battery) has been an excellent car for 5 years. I bought it in August 2018. For the last 3 months, there is an erratic behavior in battery. From 100% to about 65%, it is good. When it goes below that, a slight elevation, or acceleration drops the battery levels by 5% or above drastically. Sometimes, it drops nearly 30% in less than 2 miles. But, it recovers about some of it when slowing down. Overall, on an average, battery lasts for about 90 miles (down from 120 miles just about 3 months back before this problem started).
LeafSpy Reading (on most recent trip) : distance: 26.0, Energy: 6206, Gids: 76, SOH : 86.10%

I took the car to the dealer. They said my 12v battery is weak, and it was at 80% efficiency, and advised me replace the battery. I replaced the 12v battery. But, the problem persists. I lost trust in the dealer. Need advise please.

I also have this problem with my 2017 Leaf SV. The original battery pack was replaced under warranty for an upgraded 40kwh back in 2021. But just a couple weeks ago we started getting this erratic battery draining and fluctuation below 60% and extremely erratic below 50%.

My local dealer, Pinnacle Nissan in Scottsdale Arizona has been very helpful, and after testing for about 1.5 days, they diagnosed a "bad battery" and got Nissan to approve the warranty replacement of the whole battery again.

So we have a non-EV loaner car for a while, but at least I am fully mobile. If Nissan approves the replacement, they should also cover a car rental or loan from the dealer - that's what they are doing for me. The dealer has warned us that the battery packs come in randomly with little to no warning or regularity, so we don't know exactly when our leaf will be back to normal. It could be a week, or several months! I hope this information is helpful, and I will post an update when the repair happens for community reference.

 

[lamimartin]

I also have this problem with my 2017 Leaf SV. The original battery pack was replaced under warranty for an upgraded 40kwh back in 2021. But just a couple weeks ago we started getting this erratic battery draining and fluctuation below 60% and extremely erratic below 50%.

My local dealer, Pinnacle Nissan in Scottsdale Arizona has been very helpful, and after testing for about 1.5 days, they diagnosed a "bad battery" and got Nissan to approve the warranty replacement of the whole battery again.

So we have a non-EV loaner car for a while, but at least I am fully mobile. If Nissan approves the replacement, they should also cover a car rental or loan from the dealer - that's what they are doing for me. The dealer has warned us that the battery packs come in randomly with little to no warning or regularity, so we don't know exactly when our leaf will be back to normal. It could be a week, or several months! I hope this information is helpful, and I will post an update when the repair happens for community reference.

If you use Leafspy pro software, you may see that the milivolts (mV) difference between the cells Gets Much Higher under sustained acceleration. (Higher than 60-70mV). This is a symptom of a failing cell that can no longer be equalized by the BMS.

 

[Jerther]

If you use Leafspy pro software, you may see that the milivolts (mV) difference between the cells Gets Much Higher under sustained acceleration. (Higher than 60-70mV). This is a symptom of a failing cell that can no longer be equalized by the BMS.

That difference may also increase with lower SoC, even more so in colder weather. The defective 40kwh on my previous 2018 was fine at 90% but it showed over 300mv in the lower 30% in freezing temperatures. I got that battery replaced under warranty, but that's another story

 

[lamimartin]

That difference may also increase with lower SoC, even more so in colder weather. The defective 40kwh on my previous 2018 was fine at 90% but it showed over 300mv in the lower 30% in freezing temperatures. I got that battery replaced under warranty, but that's another story

I purchased a uses 2018 SV with 103,000km, aware of the risk of purchasing a EV out of warranty. I told myself that considering the very strong used EV depreciation, it was not much more risky than purchasing a comparable used ICE powered véhicule that may suffer of major engine or transmission damage prematurely. One thing for sure, the current cost of operation is so ridiculously low that it will pay for itself within 3 years, compared to the cost of driving my Frontier 2016 as daily driver. Rebuilding a battery is a major issue, but cost is comparable to ICE engine or transmission replacement. Current used market allow for bargain prices on EV, but fuel and maintenance cost of a gas car is not about to drop. Facing a sudden battery degradation is certainly a deception, but it is not the end!

 

[cellocolin]

I also have this problem with my 2017 Leaf SV. The original battery pack was replaced under warranty for an upgraded 40kwh back in 2021. But just a couple weeks ago we started getting this erratic battery draining and fluctuation below 60% and extremely erratic below 50%.

My local dealer, Pinnacle Nissan in Scottsdale Arizona has been very helpful, and after testing for about 1.5 days, they diagnosed a "bad battery" and got Nissan to approve the warranty replacement of the whole battery again.

So we have a non-EV loaner car for a while, but at least I am fully mobile. If Nissan approves the replacement, they should also cover a car rental or loan from the dealer - that's what they are doing for me. The dealer has warned us that the battery packs come in randomly with little to no warning or regularity, so we don't know exactly when our leaf will be back to normal. It could be a week, or several months! I hope this information is helpful, and I will post an update when the repair happens for community reference.

I just want to follow up about how this was resolved. Hopefully this is helpful to some of you experiencing the same issue.

Nissan did approve the replacement of the entire 40kwh battery. The battery came in after 3 weeks, and they replaced it right away, did some testing and charged it up. I picked it up yesterday and all appears to be normal. The service rep also told me that the new battery has a 12,000 mile warranty on it, excellent, as I was only 8,000 miles from exceeding the original powertrain warranty. Hopefully we get more than three years out of this replacement battery!

Again, Pinnacle Nissan in Scottsdale, Arizona has been extremely helpful. They took our problem seriously, made a strong case to Nissan on our behalf (quickly, too), offered us a rental car (on Nissan's dime), and completed the repair competently and quickly.

 

[hornstudio]

Could you replace a 40kWh battery by "any other" battery out of a 40kWh wreck plug and play?