Leaf 30kwh 2017, any opinion on those graphs?

[ccmm]

Hi everyone,

My name is Michael, I am based in Normandy, france.
I plan to buy a 100,000kms (62,000 miles) 2017 pre-owned 30kwh nissan leaf black edition.

It seems to be in great condition and current owner allowed me to plug a odb dongle on it.

Got those datas from leafspy. SOH seems to be good, regarding mileage. Almost 83%. Did several screen captures. Would someone with some expertise be kind enough to tell me if everything ok or if I missed something (negative) important?

Thank you in advance
Michael

 

[knightmb]

Nissan released a firmware update for the BMS of 30 kWh Leaf owners, ask the owner if that has been applied to the Leaf. The cell voltages look fine. If you can get a capture of the cell voltage when the battery is below 20% SOC, that can help to tease out if any cells look too low compared the pack. The battery is down to about 24 kWh of capacity, so expect a driving range between 96 miles (154 km) and 120 miles (193 km) if driving in ideal conditions, flat drive, minimal climate control for cooling or heating needed, properly inflated tires, etc. Once you start subtracting for uphill one-way drives and heating, expect the range to drop by 10% to 20% on a sliding scare upwards as the weather gets colder/hotter.

 

[ccmm]

Thank you knightmb for your detailed response. I heard about the firmware update for 30kwh BMS. The owner told me he never asked for it, so if it was done, nissan did it during annual service without telling him. I guess I can check with nissan with Vin number. If it has been done, is it something positive, negative or I should not care too much about it? Thanks

 

[Stanton]

At <50% SOC, a 21mV delta is fine. However, the capacity is down to that of a 24kWh pack (~66AHr).
Depending on price and what kind of range you need, it's probably a decent car (especially after >5 years).

 

[ccmm]

Hi, thanks Stanton. I will drive around 40 miles per day, to go to work. Range should be more than enough, even considering future degradation of battery pack, even in winter.

As for price, I will pay around 7000 USD (6500 euros). Sounds correct to me.

 

[Lucky]

We own the same leaf, 2016. It was still useful in warm weather @ 62% SOH but barely. In cold weather it was useless, turtle mode was instantly on. I successfully replaced the cells I got from VW ID.3.

It's not the SOH that worries me, but Hx. If it was driven hard, it might be overheated and degraded. Balance is only one indicator, but even poor cells can be balanced quite nicely. The problem is, when the cells are under load, their voltage difference rises as they have slightly different internal resistance, because they didn't age the same. (What a sentence ) Back pack gets overheated more, because cells are stacked one by another and can't cool as much. This difference in internal resistance is then the reason, that BMS (or LBC as Nissan calls it) limits the amount of power from the battery and eventually shuts it down. SOH shows the remaining capacity, but that capacity can't be used normally because of higher and uneven internal resistance. If you ask me, your state of battery is very poor.

I will give you an example:

This is the state of my first Leaf 30kWh before and after cells swap. You can notice, that the cells are well balanced on bad battery.
Also notice the SOH and Hx. Latter went from 28% to 94%. It could be 100%, but since cells are not original, their configuration is not 96S2P (96 serial with two in parallel) but 96S1P, so only 96 cells and not 192 as original has. I was aware of this and car works fine even in cold weather. Also the voltage difference could be smaller, if I took the effort of charging them within mV range. They will balance eventually...



Now this is from my other leaf, which has overheated and almost exploded battery.



This battery still has SOH @ 82%, but Hx is only 49%. Unfortunately this battery is almost dead.

So, how to test it? Plug in LeafSpy and go for a ride. Find a road which goes uphill and drive it there at least some 5 miles up. If your DASH SOC will be dropping quickly and you will get LeafSpy readings of 200mV or more, then this means that the battery is in poor health. By quickly I mean 1% every half mile or so. Then drive downhill and observe the DASH SOC. If it will be rising quickly (of course not as quick as by driving uphill), that is another confirmation of poor battery. See examples below.



Please, keep in mind, that the SOH doesn't drop linearly and that it is impossible to exactly predict when the battery will die. But when it does, it costs some money or you car is worthless. It is strange with such a low mileage.

If you would pay say 3 or 4k for it and fix the battery for another 4k, then you could have a very nice car which could serve you long time.
But if you pay 7k and then another 8k for battery, then I don't know...

I hope this serves other potential buyers too. Wish you all the best.

 

[ccmm]

Hi Lucky,
Thank tyou so much for your detailed response and the valuable information you provided.
I indeed noticed the low Hx rate but after spending some time on forums to read everything i could find from many users experience in many countries, i came to the conclusion that i should not care to much about this Hx value. I was aparently wrong.

I won't be able to do any further test unfortunately as the car is located at 300 kms from the place i live, and drove there specially last week-end to meet the owner and test the car. The car will be available next month, as the current owner is waiting for the delivery of his new car.

So now, it's on me to take the decision whether to buy it or not, with the risk it entails, based on the values and info i shared, and responses i got from persons with more expertise than i have.

However what i know: the current owner bought the car when its mileage was 30,000 kms and since then drove only flat roads, 60km every day of the week to go to work (30 in the morning / 30 in the evening, no highway). He mainly charges the Leaf at office during day time most likely from 4 or 6kwh wallbox (he bought L2 cable). The car spent most of it's life in north of france, close to belgium, where temperatures are generally quite low. He never did any QC (leafspy reported only 26QC, aparently by first owner).

Last service from Nissan in november 2023 reported "excellent battery condition" but no further details...i am not even sure they plugged anything on it...

I am not skilled enough to understand the level of risk i am takink if i buy it but i don't plan to change any cells for sure. If car became unusable > Bin!
I think i'll pass even if it was good deal on paper. If experienced electronic enginneer wouldn't take the risk, i shouldn't neither. There are plenty of Leaf on the market

If anyone has opposite experience, i mean low Hx for a long time, with no particular problem and no fast degradation preveting the car to be used, it could be interesting. After 5 years of use, i will get return on investment (i spend around 1500 dollars in fuel to go to work every year) even if it's value drop to 0.

Thanks

 

[Lucky]

Hi Lucky,
Thank tyou so much for your detailed response and the valuable information you provided.
I indeed noticed the low Hx rate but after spending some time on forums to read everything i could find from many users experience in many countries, i came to the conclusion that i should not care to much about this Hx value. I was aparently wrong.

I won't be able to do any further test unfortunately as the car is located at 300 kms from the place i live, and drove there specially last week-end to meet the owner and test the car. The car will be available next month, as the current owner is waiting for the delivery of his new car.

So now, it's on me to take the decision whether to buy it or not, with the risk it entails, based on the values and info i shared, and responses i got from persons with more expertise than i have.

However what i know: the current owner bought the car when its mileage was 30,000 kms and since then drove only flat roads, 60km every day of the week to go to work (30 in the morning / 30 in the evening, no highway). He mainly charges the Leaf at office during day time most likely from 4 or 6kwh wallbox (he bought L2 cable). The car spent most of it's life in north of france, close to belgium, where temperatures are generally quite low. He never did any QC (leafspy reported only 26QC, aparently by first owner).

Last service from Nissan in november 2023 reported "excellent battery condition" but no further details...i am not even sure they plugged anything on it...

I am not skilled enough to understand the level of risk i am takink if i buy it but i don't plan to change any cells for sure. If car became unusable > Bin!
I think i'll pass even if it was good deal on paper. If experienced electronic enginneer wouldn't take the risk, i shouldn't neither. There are plenty of Leaf on the market

If anyone has opposite experience, i mean low Hx for a long time, with no particular problem and no fast degradation preveting the car to be used, it could be interesting. After 5 years of use, i will get return on investment (i spend around 1500 dollars in fuel to go to work every year) even if it's value drop to 0.

Thanks

Hello.
There is another, yet a bit expensive point. If the car is very good preserved in general and you intend to own it "till the end", then there is also an option to run on this battery while you can and then replace the battery when it fails and use it for the rest of it's life.
As the Hx goes, I would like to be proven wrong, I'm always open for new information, if there is something new to be learned.

At least I hope you have enough information to make your decision.

Wish you all the best.

 

[lorenfb]

Hi Lucky,
Thank tyou so much for your detailed response and the valuable information you provided.
I indeed noticed the low Hx rate but after spending some time on forums to read everything i could find from many users experience in many countries, i came to the conclusion that i should not care to much about this Hx value. I was aparently wrong.

I won't be able to do any further test unfortunately as the car is located at 300 kms from the place i live, and drove there specially last week-end to meet the owner and test the car. The car will be available next month, as the current owner is waiting for the delivery of his new car.

So now, it's on me to take the decision whether to buy it or not, with the risk it entails, based on the values and info i shared, and responses i got from persons with more expertise than i have.

However what i know: the current owner bought the car when its mileage was 30,000 kms and since then drove only flat roads, 60km every day of the week to go to work (30 in the morning / 30 in the evening, no highway). He mainly charges the Leaf at office during day time most likely from 4 or 6kwh wallbox (he bought L2 cable). The car spent most of it's life in north of france, close to belgium, where temperatures are generally quite low. He never did any QC (leafspy reported only 26QC, aparently by first owner).

Last service from Nissan in november 2023 reported "excellent battery condition" but no further details...i am not even sure they plugged anything on it...

I am not skilled enough to understand the level of risk i am takink if i buy it but i don't plan to change any cells for sure. If car became unusable > Bin!
I think i'll pass even if it was good deal on paper. If experienced electronic enginneer wouldn't take the risk, i shouldn't neither. There are plenty of Leaf on the market

If anyone has opposite experience, i mean low Hx for a long time, with no particular problem and no fast degradation preveting the car to be used, it could be interesting. After 5 years of use, i will get return on investment (i spend around 1500 dollars in fuel to go to work every year) even if it's value drop to 0.

Thanks

Yes, Hx is a key battery parameter as it ages, i.e. it's a measure of the conductivity (inverse of resistivity) of the battery cells.

 

[ccmm]

Hello.
There is another, yet a bit expensive point. If the car is very good preserved in general and you intend to own it "till the end", then there is also an option to run on this battery while you can and then replace the battery when it fails and use it for the rest of it's life.
As the Hx goes, I would like to be proven wrong, I'm always open for new information, if there is something new to be learned.

At least I hope you have enough information to make your decision.

Wish you all the best.

Thank you for your help lucky

 

[ccmm]

Yes, Hx is a key battery parameter as it ages, i.e. it's a measure of the conductivity (inverse of resistivity) of the battery cells.

Thank you lorenfb. So you agree with lucky, that hx at 55% is a sign of poor battery state and not worth take the risk to buy?

 

[ACDCPhilip]

I had a 2016 30kwh Leaf that I sold around 6 months ago.
It had around 56% Hx when I sold it.
The person buying it lived 170 miles ( 272Km ) away & I agreed to deliver it for him.
Drove at around 55mph & just charged once from about 25% back up to 98% around half way there, arrived with about 20% charge left.
That didn't indicate to me that there was any problem with the battery.

I'm not saying that the one you have looked at will be the same, but I wouldn't let that Hx figure put you off if it's current range, which I assume would be about 90 miles in summer is sufficient for your needs.
At 6500 Euro, seems like a good buy.

By the way, your Leafspy screenshot shows the 12v battery @ 11.76 which indicates it will probably need replacing.
Perhaps you can negotiate a bit more discount for the low Hx & replacement 12v.

 

[Lucky]

Yesterday I recorded a video of driving Nissan Leaf 2019 with the intent of showing how can a battery with still good SOH number of 82% and bad Hx at 49% really behave in very moderate cold (10°C). I think everyone should make this test before buying and even without of LeafSpy. The results tell me, that the SOH by itself is really a poor indicator of battery health. Also dash indicator still shows 11 bars.

The test is very simple, I drove the car 5km uphill where it almost stalled, so I took it from the road the first possible moment and ended on some muddy road. Then I turned and went another 5km downhill. What you will learn is what I learned also: Don't trust solely on the indicators and readings. You must test your Leaf and it must be a bit of stress test, at least a couple of miles uphill.

Here is the video:

Hope this helps more then it confuses

 

[ccmm]

Thank you lucky. Sorry, could not respond earlier. That's a really informative video. It does not confuse at all but I am surprised that almost no one mention this issue with low hx rate, maybe because most users use drive them on flat city centers? The only thing I did not understand is how can soc displayed from leafspy remains stable at around 40% when it drops on leaf's display? Aren't those value supposed to be read/supplied by BMS, thus should be identical or at least similar? Thanks again for the valuable information provided.

 

[knightmb]

Yes, actually quite an interesting video. First, the battery wasn't freezing, so a reduction in power wouldn't be necessary for the BMS. But before you started to drive, it was already reducing your "top" end acceleration power, which might mean is was close enough to freezing to reduce power?

When I saw the number of QC sessions, I just have to ask. Do you use your Leaf as a taxi / ride share service?

I saw a big gap of 371 mV and further into your drive I could see nearly half the cells were part of the large gap in voltage. I was expecting full power most of the way, but it seems you were doing your best not to strand yourself. All the way up, it was reducing top end power a little more each passing second. Once the weakest cell got under 3.0 V I could see the turtle mode came up immediately. I saw one cell dip as low as 2.3V which I'm surprised the pack didn't shut off, but I think for safety reasons it gives you turtle first as a greatly reduced power, perhaps hoping the weakest cell will recover enough to avoid that.

There are some things you can try on this pack to see if you can balance out the pack better, granted it won't fix any cell issues, but it's a way to try to reduce some range issues that doesn't require taking the pack apart. I can save that for another topic though as to avoid creating too much of a sidetrack for this one.

 

[lorenfb]

Thank you lorenfb. So you agree with lucky, that hx at 55% is a sign of poor battery state and not worth take the risk to buy?

Yes, that's a good assumption.

 

[Lucky]

The only thing I did not understand is how can soc displayed from leafspy remains stable at around 40% when it drops on leaf's display? Aren't those value supposed to be read/supplied by BMS, thus should be identical or at least similar?

Hi. Now I'm a bit late after a couple of feverish days. It looks like the BMS (or LBC) reports the real numbers to the dash, but the dash computer adjusts the displayed SOC to be in tandem with GOM, otherwise it wouldn't make sense to the driver. So there is stil juice in the battery, but it cannot be pulled out of it with the speed required from the motor, because of the big differences in internal resistances of the modules.

 

[Lucky]

Yes, actually quite an interesting video. First, the battery wasn't freezing, so a reduction in power wouldn't be necessary for the BMS. But before you started to drive, it was already reducing your "top" end acceleration power, which might mean is was close enough to freezing to reduce power?

It was around 10°C, absolutely no freezing.

When I saw the number of QC sessions, I just have to ask. Do you use your Leaf as a taxi / ride share service?

No, I bought this car to fix it and then we'll se if we keep it for my wife or sell it.

I saw a big gap of 371 mV and further into your drive I could see nearly half the cells were part of the large gap in voltage. I was expecting full power most of the way, but it seems you were doing your best not to strand yourself. All the way up, it was reducing top end power a little more each passing second. Once the weakest cell got under 3.0 V I could see the turtle mode came up immediately. I saw one cell dip as low as 2.3V which I'm surprised the pack didn't shut off, but I think for safety reasons it gives you turtle first as a greatly reduced power, perhaps hoping the weakest cell will recover enough to avoid that.

It was a bit challenging and it almost stranded me. I didn't expect it to be so bad, otherwise I wouldn't even do it. I didn't even notice cells going so low. It looks like it allows it for some short time and you are right, for safety reasons

There are some things you can try on this pack to see if you can balance out the pack better, granted it won't fix any cell issues, but it's a way to try to reduce some range issues that doesn't require taking the pack apart. I can save that for another topic though as to avoid creating too much of a sidetrack for this one.

Before buying this car, I was at the Nissan dealer where they had the pack opened and I could se the modules. Trust me, there is no saving of this pack. It is so inflated it almost tore the screws apart. I ordered new cells as soon as I got the car on my name, so I wasn't ever thinking on repairing anything. I'll post some pictures when I completely heal.

 

[ccmm]

Hi. Now I'm a bit late after a couple of feverish days. It looks like the BMS (or LBC) reports the real numbers to the dash, but the dash computer adjusts the displayed SOC to be in tandem with GOM, otherwise it wouldn't make sense to the driver. So there is stil juice in the battery, but it cannot be pulled out of it with the speed required from the motor, because of the big differences in internal resistances of the modules.

Yep, makes sense. Thanks a lot!

 

[danelo]

A lot of useful information here.

What I am getting from this thread is that Hx is very important if you live in an area that has a lot hills. Seems like Hx is almost a measure of how much hard work the battery can do. A slightly poor Hx number is probably not so much of an issue if you are in an area that is mostly flat.

So at what percent is Hx considered bad? Looks like around 50% is bad, but is 70% or 85% bad?