Battery 17% sudden drop while driving

[user546379]

Hello Leaf drivers,

BACKGROUND INFO:
I am the original owner of a 2020 Leaf S with 40 kWh battery. No prior issues with the car. I almost always charge at home using 30 amps at 240 volts with the original charger supplied by Nissan. Have never charged at a faster rate than that. Default driving mode is ECO, with frequent use of the "B" gear for extra regen braking, as well as cruise control. I live on Oahu in Hawaii, so the ambient temperature is almost always between 70 and 85 degrees F. The terrain is mountainous, and my daily commute includes an 800 ft elevation gain and drop at a speed of 55 mph each way. I've generally ignored the "range" estimate shown on the dash display as I assume it doesn't "learn" that I drive over a mountain every day. Rather, I monitor the % charge. I aim to charge when the charge level is 30 to 40%, and I use a timer to limit the charge level to 94% or less so that I don't lose regen braking. On September 7, 2023 a dealership installed the NTB23-057 recall software update. They also did a battery health check which showed "perfect" results on the same day.

STATEMENT OF PROBLEM:
Today I was driving uphill at 55 mph, when the % charge instantaneously dropped from 18 to 5%. The warning light also came on. I was not using the A/C at the time. Over the next 30 seconds or so, the gauge quickly went from 5...4...3...2....1. By dumb luck, as the gauge hit 1%, I hit peak elevation on the mountain pass, and was able to coast in neutral until the freeway starts going downhill. I then coasted in D-ECO, and the charge level eventually went up to 12% (though not smoothly 1,2,3,4,5...12). This was sufficient to get me home.

QUESTIONS:
Does this story indicate a faulty battery, or just a bad estimate by the battery management system of the battery capacity? Will a 2020 Leaf automatically "learn" that the 18% estimate was way off, and recalibrate it's percentage scale after such an incident? If so, does that imply that overall battery capacity has degraded significantly (even enough to trigger a warranty claim)? Is there any recommended action on my part (e.g. fully charge to 100%, buy a LeafSpy device).

Thanks to anyone who can advise.

 

[LeftieBiker]

This sounds like one or more cells in the battery are going South. You need to use LeafSpy Pro to get a depiction of the battery cells and the voltage variations between them. Hawaii is kind of deceptive, in that while you don't usually get extreme heat, the generally warm/very warm nights prevent the batteries in EVs without active cooling (like the Leaf) from cooling down.

 

[Stanton]

I'll add the 40 kWh packs in your time frame are notorious for having bad/weak cells/modules. I know because I had one (and "fixed" it) that I upgraded my Gen1 Leaf with.

 

[user546379]

So per LeafSpy pro, the battery pack is fine with no bad cells. Overal SOH is 90%.
There's an active discussion on this at: https://www.reddit.com/r/leaf/comments/16hski4/nissan_leaf_battery_sudden_drop/
Seems like many folks are having this issue, some before a software update, and some after the software update.

 

[ebeighe]

@user546379 so over on reddit thread it looks like you are in line for a warranty replacment as of a couple of weeks ago, correct? How is the timeframe?

 

[decimal]

Do you ever do a 'balancing' charge of the battery to 100%?
Might be worth charging overnight to maximum capacity and then see what Leaf Spy Pro reports the total capacity to be in kWh. Do a test drive with the dongle connected and watch what the kWh drop is as you drive normally. Could be an issue with the BMS mis-reporting SOC rather than a hardware fault with the battery cells.. although there do seem to be issues with some batteries used in the Leaf in the USA that do not seem to affect EU cars in the same way. Would be good to rule-out a software issue.

 

[dwl]

Unfortunately this problem is not uncommon where there are loads such as long steep hills. I have had it on my 2018 and a local survey here in New Zealand showed for the same highway which requires about 3 minutes of power at around 50-60kW that several other 40 kWh cars have same issue, The battery has capacity which if used at moderate rates is the same for all cells (balance same at high and low SoC). It is only when more is demanded that some weaker cells cannot deliver the sustained power and sag but recover SoC when load removed. The issue seems to be more obvious when battery cold and lower SoC. Probably not worth trying to fix with my example and if an issue next winter just sell to someone who doesn’t have this big long climb needing higher power. [signature for first Leaf, the one above is 2018 40kWh now with 66,000 km]

 

[TronJockey]

So per LeafSpy pro, the battery pack is fine with no bad cells. Overal SOH is 90%.
There's an active discussion on this at:
Seems like many folks are having this issue, some before a software update, and some after the software update.

LeafSpy may not detect this if you're scanning the battery after it's been fully charged. I had a similar issue with my brand new 2019 SV Plus. It would operate as if normal when above 50%. At around 45% (at highway speed) the display would become erratic for a minute or two then emerge as if nothing had happened but with a new percentage of only 25%. Somehow, I had lost 20% of my range in just a minute or two. Using LeafSpy just after this occurred revealed that battery module #40 was discharging far faster than all the other modules. Battery module #40 eventually died completely after I decided to continue driving the car down to 0%. All the other modules recharged after that but module #40 finally gave up completely.

 

[Bombastinator2]

*immediately buys the leafSpyPro app because it sounds really cool*

What’s this about a Bluetooth adaptor btw?

 

[LeftieBiker]

You need one to plug into the OBDII port under the left side of the dashboard. Your android phone (cheap used ones with no cell service are fine) then connects to the dongle via Bluetooth and the app reads the battery info from the CANBUS system. The one listed in my signature works fine and isn't too expensive.

 

[cornbinder89]

How do you download Leafspy to a phone with no link to the internet (not activated)? It seams that you would need at least one phone or device running Android that can connect to be able to "side load" to the inactive phone. I have no Android devices.

 

[Bombastinator2]

How do you download Leafspy to a phone with no link to the internet (not activated)? It seams that you would need at least one phone or device running Android that can connect to be able to "side load" to the inactive phone. I have no Android devices.

I’ve only got an iPhone.. So I only dwnloaded the phone stuff. I have to “agree” and stay agreed (so Nissan effectively lojacks my car and sells the data to anyone who wants to abuse me with it) for the thing to work?! Fffffffff….. I actually pulled the SD card from the map thing to shut that down so I could “disagree” again. I only even put it back because it was so annoying to drive without it. If I’d even thought they might do their customers that dirty I probably wouldn’t have bought the car. Heck if it was in all electric cars I probably would even drive ICE to avoid it. I am not fricken company property and neither is my car. Learning that piece of knowledge has already made me so angry I will never buy a car again from the people that do it. Screw all the lies the ultra right tells about electric cars. If all of them did it that one fact alone would be enough to destroy the American market. Theres a reason none of the American manufacturers do it. That one fact is big enough to make no one buy a car like that. Phone companies can do it too but they don’t dare without permission (which basically no one intentionally gives) At least they know better. Apple did it without thinking and lost marketshare over it so they’re more careful now. If I even THOUGHT Nissan did it before I bought the car I would never have walked into the dealership.

 

[LeftieBiker]

How do you download Leafspy to a phone with no link to the internet (not activated)? It seams that you would need at least one phone or device running Android that can connect to be able to "side load" to the inactive phone. I have no Android devices.

All you need to do is connect to the dongle using Bluetooth and download info with that. No internet needed.

 

[cornbinder89]

You still need to get Leafspy into the phone! The phone can't do anything without the program!
Put another way:
youmust get the app onto the phone, to do that the phone must be connected to the internet even if only one time. 'Again, how do you do that when the phone is not activated?
Yes I know it doesn't need an internet connection to read the cars info, but it does need one to get the app

 

[decimal]

You still need to get Leafspy into the phone! The phone can't do anything without the program!
Put another way:
youmust get the app onto the phone, to do that the phone must be connected to the internet even if only one time. 'Again, how do you do that when the phone is not activated?
Yes I know it doesn't need an internet connection to read the cars info, but it does need one to get the app

Yes, you need internet to download an app. That's the case with all apps though..

 

[cornbinder89]

Yes, you need internet to download an app. That's the case with all apps though..

Yes, I know, but programs I download aren't limited to Android OS! There are people here advocating that you don't need a phone that is activated. I just don't see how that works. Yes you can use an older phone that is no longer active with an account, but not how you can download to a phone that doesn't have an account.
If I could download to a Linux based machine, I might have a possibility to run it with an Android emulator for that operating system. So far any of the App stores stop any attempt because my stuff isn't running Android.

 

[Ethel's Dad]

Hi fellow Leafers!

I have recently noticed something similar with my Jan-2020-reg 39kW Leaf, my first EV which I've had close to 2 years. I make a regular evening journey of 16 miles out (nett downhill), a 2-hour stop then the same route back (nett uphill). The typical cost of this is ~7% out plus ~14% back, rising to ~30% total in winter.

A couple of weeks ago the weather here (northern England) was 0C and dry, and I set off with 77% charge and arrived with 63%. Halfway back it showed 43% as I started to accelerate to 50 mph for a two-and-a-half-mile gradual climb, and before I reached the top it had plummeted to around 15%, recovering to ~30% as I eased off over the brow. On arrival at home it showed 15%. Charging to 100% at home took 22.2 kWh, which suggests that the real SoC was around 40% ish.

The same journey a week later, with temperature +3C and dry, and a starting SoC of 92%, got me there on 80% and back home on 60%, which looks reasonable. This backs up other posts which suggest the problem occurs at low temperatures with SoC below around 50%.

Is there an "official" report on what's going on here, or do we rely on the user community? I have had a more worrying incident on a similar journey, where I encountered 5% and a "Charge NOW!!!" warning 4 miles from home, even though there was ~30% still in the battery.

Thanks guys.

 

[Chad E. Mo]

@Ethel's Dad, the general consensus is to use the LeafSpy Pro app to examine the status of the modules in the battery.

The likelihood is one or more is failing, and becoming more evident under high load at low temperatures.

 

[Ethel's Dad]

@Chad E. Mo I don't have any fancy apps or dongles or the like. I've had the software update late last year, and just had a service where the dealer was very keen - perhaps too keen? - to tell me how good my battery was. A cynic might think that the manufacturer was aware of a problem which they couldn't afford to fix for everyone.

 

[Bouska006]

Does anyone have a specific OBDII dongle that has worked with the LEAF and LeafSpy? There are so many super cheap to quite expensive; some require their app to be downloaded, etc.