The 40KWH Battery Topic

[kovadam]

Hi!

After 1723km and 4 weeks of ownership I almost down to 99% according SOH. The daily 0.01-0.02% drop continues every day no matter if I charge to 100% and leave it so for hours (or half a day) or keep it around 80%, whether I only do L2 or I do Chademo. I start to think, that the SOH value in LeafSpy does not have anything to do with real SOH. The AHr is dropping also continuously the Hx is keeping rising. Current values are:

AHr: 114.38
SOH: 99.08%
Hx: 106.64%
Cell delta when charged to 100%: 9mV

I don't know what AHr means, I guess Ampere hours, If yes, it cannot be true. If you multiply it with the Pack average voltage like 370V you get over 42kWh, which is more than the calculated 39.6kWh max capacity. (if multiplying with 400V you get even higher)

The only thing what gives some idea about degradation are the GIDs. I still can charge the car to 498GIDs, and if I assume (from LeafSpy) that 500 is the max for 40kWh pack, it is 99.6%, and it is quite steady, since I got the car it was always like this. I once managed to charge to 501 GIDs, but I think that was only a mistake reading.

Although I don't know if the above values are read directly from the CAN bus messages or are calculated based on some values, but I think the 2018's Leaf BMS is sending the data totally different way to CAN bus, and values cannot be used the same way like with older Leafs.

Regards

kovadam

[WetEV]

[quote="kovadam]"I start to think, that the SOH value in LeafSpy does not have anything to do with real SOH.[/quote]

The SOH in LeafSpy is the estimate from the car's battery controller. It is not a measurement. Changes less than 3% probably mean nothing.

[kovadam]

What I mean is, that in 2018 Leaf it is not even an estimate value from the BMS, it is some value interpreted totally wrongly as SOH, I think this value has nothing to do any more with SOH. A new analysis should be done on the 2018 Leaf CAN bus messages to see if the messages are still the same (since there are some things which are different on CAN bus as on previous Leafs).

BTW: if they are the same, and this really means the SOH, I will get a new battery after 3-4 years... and it seems everyone who is owing a new Leaf

[cwerdna]

After 1723km and 4 weeks of ownership I almost down to 99% according SOH. The daily 0.01-0.02% drop continues every day no matter if I charge to 100% and leave it so for hours (or half a day) or keep it around 80%, whether I only do L2 or I do Chademo. I start to think, that the SOH value in LeafSpy does not have anything to do with real SOH. The AHr is dropping also continuously the Hx is keeping rising. Current values are:
...

The only thing what gives some idea about degradation are the GIDs. I still can charge the car to 498GIDs, and if I assume (from LeafSpy) that 500 is the max for 40kWh pack, it is 99.6%, and it is quite steady, since I got the car it was always like this. I once managed to charge to 501 GIDs, but I think that was only a mistake reading.

I had to look up you to see if it was you who I replied to earlier.

I still say, who cares? These values will continue to fluctuate and will have some variance. Even the # of gids on a full charge will vary, It's not like the battery has some magic output value that tells the car remaining capacity. They only have +, - and temperature sensors. You should just look at the long term trend. Let's see what it looks like in 2 or 3 years.

I posted my capacity bar loss at http://www.mynissanleaf.com/viewtopic.p ... 15#p511915 from Nov 2017. Back then, Leaf Spy would only show whole numbers for SOH. That day it was 83%. Skimming thru my trip logs, I've had periods of time after that where SOH became was high as 86% but I was still missing a capacity bar. It never came back.

Looking at the latest entries and going back about a month, my SOH is now typically 83.xx% to 84.xx%.

[kovadam]

Well it fluctuates with prevois leafs, but does not fluctuate with the new. It just goes down. This is why I think that the value in Leaf Spy is not right any more. It interprets some integer values as SOH which has nothing to do with SOH like in previous leafs.

[cwerdna]

Well it fluctuates with prevois leafs, but does not fluctuate with the new. It just goes down.

Big deal. You may see a trend of SOH and gids on a full charge being lower as temps decline and them picking back up once the weather gets warmer.

From glancing thru my 10/2017 thru 2/2018 SOH values quickly, that seems to be the case. Can someone else chime in who remembers or has checked their numbers? Let's see where yours are at in Feb or March 2019.

To me, you're worrying needlessly. Why?

[LeftieBiker]

You aren't looking at a brand new Leaf trending only downward, Cwerdna. I have no stats for my 2013's first year, but the 2018 has declined faster with warmer temps, IIRC, rather than improved. Maybe all of these cars will stabilize this Winter, and if they do I'll worry less at that point.

[kovadam]

Well here the max temp for the last 4 weeks was like 25°C, but mostly around 22°C. In night it goes down to 6-9°C mostly. My battery pack is always around 17-25°C (parking in a garage, where the temp is still above 20°C), sometimes going around 30°C (when going on the motorway).
The highest I saw was 37°C, when I was to Budapest (started with battery temp 17°C), drowe 120km on motorway (110/120km/h), and I did a 30 min long QC after a 2 hour Type2 charging, then some hours later driving home on the Motorway doing 110/120km/h over 130km long. At the end when I exited the motorway the battery temp was slightly above 37°C, but started to drop immediately i reduced the speed in the city, and I arrived home ~36°C, next morning it was 27°C. The battery temp gauge never was above the midpoint, mostly it is one section below midpoint. So the degradation cannot be the temperature, as the battery is mostly at it's optimal temperature (20-25°C, I only did two long journeys using motorway and high speed).

[DaveinOlyWA]

TBH; I post my info only so others can see it. What you do with it is up to you. I opted for the 40 kwh LEAF because it was the best deal available to me by quite a bit. Now we can chime in with our great Bolt deals or whatever but I missed that window so it means NOTHING to me. In reality, I missed the great LEAF deals (which are going on right now) but it is what it is.

But unlike the previous LEAFs, I am not in a position where I am in trouble if I lose 15% of my range so if SOH whatever it measures says I have lost 5% I really don't care because the range is what I am concerned about and my ideal is

1) Lose less than 15% in first 100,000 miles

or

2) lose it fast enough to get new pack at 80 or 90,000 miles

because in either situation, I still have enough range left to make the car work.

But I see too many people chime in with "I have 120 mile commute and wondering if the new LEAF will be ok for me. I "try" to keep it under 75 as much as possible" posts...

I mean... you know. Its like EV Emergence Day One over and over and over...

[kovadam]

Hi!

I discovered an interesting picture on Nissan UK's website:

https://www-europe.nissan-cdn.net/conte ... .smart.jpg

I found this on this site:

https://www.nissan.co.uk/vehicles/new-v ... rging.html

Looks like there is a FAN on the side of the battery pack???? I never saw anything like this on any videos/pictures about the Leaf battery pack.