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Hi,

It's running the original code for the BMC 4NR4A. I have booked in a service and MOT in September, so will ask them to update the code and see if SOH recovers. One strange thing is my car's instruments cluster reports only one bar down, but LeadSpy is showing SOH 72%. Nissan may not give a replacement battery until the car is displaying 8 bars or less from my understanding.

Thanks,
 

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Personally i'd book in for the update sooner and get it done, and then book the MOT elsewhere, its just easier normally :)

With the update and your current level there is a chance you could get back upto 85% or more looking at the other values and mileage. At least if the bar doesnt come back your closer to a warranty swap out as well :)
 

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Hi,

It's running the original code for the BMC 4NR4A. I have booked in a service and MOT in September, so will ask them to update the code and see if SOH recovers. One strange thing is my car's instruments cluster reports only one bar down, but LeadSpy is showing SOH 72%. Nissan may not give a replacement battery until the car is displaying 8 bars or less from my understanding.

Thanks,
New SoH = 53 + Current SoH x 0.43

New SoH should be 84.1% after update

Sent from my SM-G973F using Tapatalk
 

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New SoH = 53 + Current SoH x 0.43

New SoH should be 84.1% after update

Sent from my SM-G973F using Tapatalk
Without digging back through many pages, where is this formula derived from ? Is it just empirically curve fitting to reported results of the update or based on something a bit more ?
 

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Without digging back through many pages, where is this formula derived from ? Is it just empirically curve fitting to reported results of the update or based on something a bit more ?
I think I saw it on Flip the fleet which had lot of info on firmware update.
Very likely empirical but I haven't seen anything that deviates

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I think I saw it on Flip the fleet which had lot of info on firmware update.
Very likely empirical but I haven't seen anything that deviates
You mean this article ?

 

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You mean this article ?

That is one of the main ones. They mention linear equation but I think the equation is mentioned elsewhere

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Car is booked into Nissan next month. The service manager has never come across the firmware battery update before. So, I may have to pay a diagnostics fee....
 

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Car is booked into Nissan next month. The service manager has never come across the firmware battery update before. So, I may have to pay a diagnostics fee....
Do not pay for it. It's free. Find another dealer of you have to. Call Nissan Customer and raise a complaint if you have to.

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When I was looking for a second EV (under 40k miles), I saw a few Leafs and using leafspy the highest %SOH wierdly was 63 plate Leaf with 36k miles, %SOH=96%. It was usually charged once a week on granny charger. I couldn't agree a price unfortunately.

The worst ones were 30kwh, which had %SOH between 78% and 86%. Nissan should have added at least some air cooling to 30kwh and 40kwh.

I ended up buying a Soul EV 30kwh six weeks ago (%SOH=100 @ 33 months - 36K miles, my actual average is 5.9 miles/kwh, GOM (under) estimates 152 miles on Full Charge).
 

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I think its down to usage and how often the battery is getting hot & staying at high SoC.
The problem with the Kia/Hyundai units is that they have a built in big buffer that hides the degredation, ie the 64kwh kona is more like nearly 68kwh in the actual pack so can lose 6% SOC before it actually drops below the stated capacity.
Nissan i have run differently and batteries like the 30kwh are more like 26kwh on a good day, and the 40kwh more like 37kwh...

it all adds up and i think Kia/Hyundai have this sewn up as fairer advertising as to what it can do.
 

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When I was looking for a second EV (under 40k miles), I saw a few Leafs and using leafspy the highest %SOH wierdly was 63 plate Leaf with 36k miles, %SOH=96%. It was usually charged once a week on granny charger. I couldn't agree a price unfortunately.

The worst ones were 30kwh, which had %SOH between 78% and 86%. Nissan should have added at least some air cooling to 30kwh and 40kwh.
I wonder if the 30kWh models you looked at had the earlier BMS firmware that under reported the true SoH ?
The problem with the Kia/Hyundai units is that they have a built in big buffer that hides the degredation, ie the 64kwh kona is more like nearly 68kwh in the actual pack so can lose 6% SOC before it actually drops below the stated capacity.
Nissan i have run differently and batteries like the 30kwh are more like 26kwh on a good day, and the 40kwh more like 37kwh...
I'm not so sure that the 30kWh is a lie on the Leaf. Going by the range I have actually achieved (driven down to 11 miles left) and the claimed miles/kWh the car reports over said journey, it works out to 27.4kWh usable capacity on mine. Reported SoH is 92.4%. Calculate 27.4 / 0.924 and you get 29.65kWh if the car had a 100% SoH. Seems reasonable to me ?

It's clear that the Kia and Hyundai have a significant buffer kept in reserve though like you say, so will probably show "no" degradation until the point where that buffer is used up. Another way to look at it would be that they sell the car with a SoH of 106% of the claimed usable capacity, but cap the SoH reading to 100%. So you don't see any loss until the true capacity degrades below the advertised 64kWh.

It's all about how you interpret the numbers.
 

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@Kingpleb1

Factors that imo effect degradation
  • Battery Temperature
  • regular charge %SOC (80% or 100%)
  • Lack of adequate Cooling
  • Bad Monitoring/Management Software
  • number of Rapid charges (heat)
I agree that High Temperature is the biggest factor on battery degradation. Doesn't matter if its because of rapid charges or hot climate.

Due to my required weekly range (around 110 miles), I can get away with granny charge to around 80% per week and 100% per month (as per manual). This in theory (and the battery manufacturer documents) also helps prolong the battery life. The last 20% of battery charge are also slower, I assume due to the heat produced. Tesla (even with best battery cooling and best BMS software) only recommend you charge to 100% if you plan to go on a long trip.

I am horrified at the Battery Temperatures on rapid charges of the new Leaf when I watch TeslaBjorn videos (best EV reviewer ever), considering he is Norway and not Arizona.
 

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@Kingpleb1

Factors that imo effect degradation
  • Battery Temperature
  • regular charge %SOC (80% or 100%)
  • Lack of adequate Cooling
  • Bad Monitoring/Management Software
  • number of Rapid charges (heat)
You forgot depth of discharge. Deeply discharging a Lithium Ion cell causes dramatically more degradation than two partial discharges (with a top up in between) travelling the same distance all else (temperature etc) being equal.

Number of rapid charges is not a good metric, if the battery is cool (winter) it's not harmful. Time spent too hot at a high SoC is what matters.
 

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I have to admit, at the rate the battery is declining in mine, I'm tempted part ways with it before the loss of the first bar impacts resale value. Decisions decisions....
 

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I wonder if the 30kWh models you looked at had the earlier BMS firmware that under reported the true SoH ?
Could well be! But whats to say the new update has a bug skewed the other way, sounds to me like they don't actually know how to calculate the real %SOH.

Have people actually had more tangible range increase than before? If so, is that still the case after a month or longer?

Or is it like Mitsubushi Outlander Phev (my wife's car). The Mitsubishi BMU software is really bad (possibly the worst ever) but luckily can be reset in 20 secs (Dublin method) and you do get 10% more miles than before the reset. Though the buggy software means that you need to do this every couple of months.
 

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@DBMandrake
You're right. I have never let %SOC go below 20%

Would you buy a car from someone who lives in a flat and only charges for free at Nissan dealers Chademo?
 

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Could well be! But whats to say the new update has a bug skewed the other way, sounds to me like they don't actually know how to calculate the real %SOH.
The article I linked to discusses how the usable capacity of the battery pack was independently measured and verified on several cars pre and post firmware update and compared to the reported figures from the BMS, and they confirmed that the original firmware was indeed under reporting the SoH, more so for lower SoH cars and by as much as 17%. They also verified that the post firmware update figure correlated very closely with the independently measured battery capacity.

Normally I would be as suspicious as you that an update didn't just fudge the numbers higher to avoid warranty claims, but it seems that in the case of the 30kWh Leaf the update genuinely addresses an under reporting of SoH and that the new firmware gives an accurate indication of true SoH.

How this mistake happened in the first place I don't know, however it's interesting that the mistake resulted in little to no error for cars at nearly 100%, so perhaps that's why it wasn't caught. Perhaps the firmware was never tested on an actual degraded battery before release...
 
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