The 40KWH Battery Topic

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LeftieBiker said:
I did what may be the last LeafSpy reading on my 2018 yesterday evening.

SOH: 90.36

AHr: 104.31

Hx: 105.80%

Odo: 4420

SOC: 76.6%

Cell variance: 18mv

That's an average degradation rate of 3.12% per year. Mine has followed the typical 40kwh pattern of a single rapid loss the first year, followed by much lower drops afterwards.

Based on your expectation; how many more years to lose a bar if it drops exactly at 85%? You are 2-4% higher than most I know with similar age car but they have much more miles than you. You might make a good case for a time only based degradation chart?
 
I'm figuring two more years at least until the first bar loss. Maybe the correct predictive factors are time plus mileage, with heat also a factor. We are considering buying the car off lease, now that we have an SV Plus for longer trips. My housemate prefers driving the SL, as do I. Since it's guaranteed to have at least 90 miles or so of range for 8 years from new, it's unlikely that we'd find it lacking in range in that period. I'd also be using a Gold Preferred Plus warranty to extend the Bumper to Bumper warranty to six years from new. That's pricey ($2200) if bought locally, but it's a reasonable $829 from one of the dealers who sell it nationally.
 
LeftieBiker said:
I'm figuring two more years at least until the first bar loss. Maybe the correct predictive factors are time plus mileage, with heat also a factor. We are considering buying the car off lease, now that we have an SV Plus for longer trips. My housemate prefers driving the SL, as do I. Since it's guaranteed to have at least 90 miles or so of range for 8 years from new, it's unlikely that we'd find it lacking in range in that period. I'd also be using a Gold Preferred Plus warranty to extend the Bumper to Bumper warranty to six years from new. That's pricey ($2200) if bought locally, but it's a reasonable $829 from one of the dealers who sell it nationally.

Assuming no chemical changes from 40 to 62 kwh pack, I would have a hard time considering heat as a factor. Too many people in very warm areas are in lockstep with northern tier LEAFers. In collecting ongoing LEAF Spy data, its seems the pattern is 6-8% loss year one, 1-3% loss year two then under 1% after that. This covers a pretty wide range of miles driven from very few like you to over 100,000 miles.

It seems that ones who lost the bigger chunks early slowed down sooner so despite the rather wide range of values, they all seemed to have merged into a group that is within 2% of each other. Very...interesting.
 
I finally had a "big" adjustment downward which is a bummer but to be expected. After owning this car for about 30 months I'm personally convinced that SOH degradation is more a factor of time than mileage.

Data logged on 04/11/21:

SOH: 90.37%
AHr: 100.86
Hx: 104.72
QCs: 27 (typically 20-30min & max 36kW due to a 100A charger limitation)
L2's: 1279 (typically 90-120 min session between 1am-7am depending on the season)
ODO: 35,414 mi
 
HerdingElectrons said:
I finally had a "big" adjustment downward which is a bummer but to be expected. After owning this car for about 30 months I'm personally convinced that SOH degradation is more a factor of time than mileage.

Data logged on 04/11/21:

SOH: 90.37%
AHr: 100.86
Hx: 104.72
QCs: 27 (typically 20-30min & max 36kW due to a 100A charger limitation)
L2's: 1279 (typically 90-120 min session between 1am-7am depending on the season)
ODO: 35,414 mi

How is our AHr the same but different SOH?
 
danrjones said:
HerdingElectrons said:
I finally had a "big" adjustment downward which is a bummer but to be expected. After owning this car for about 30 months I'm personally convinced that SOH degradation is more a factor of time than mileage.

Data logged on 04/11/21:

SOH: 90.37%
AHr: 100.86
Hx: 104.72
QCs: 27 (typically 20-30min & max 36kW due to a 100A charger limitation)
L2's: 1279 (typically 90-120 min session between 1am-7am depending on the season)
ODO: 35,414 mi

How is our AHr the same but different SOH?
I treat them as the same too but different scales, although I presume there are more subtle differences that show up from time to time to have made it worth Nissan's trouble to make both.
 
Assuming no chemical changes from 40 to 62 kwh pack, I would have a hard time considering heat as a factor. Too many people in very warm areas are in lockstep with northern tier LEAFers.

I'm talking about the 40kwh pack only. The bigger battery seems to have enough thermal mass - and more available power output - to moderate its temperature.
 
LOL

I am not sure that answered my question. Maybe we just don't know. Weird though to have same AHr and 3% different SOH

I am winning though for the lowest HX! :D
 
I've been thinking the same thing for a while. It almost seems the SOH is just an estimate based on time, temperature, probably a few other inputs. Its accuracy is anyone's guess. The only true test is still an external range test. The nice thing about that is it's impossible to get to tenths of a % accuracy so one doesn't have to fret over every single little drop.
 
danrjones said:
How is our AHr the same but different SOH?

The short answer is I have no idea.

Thinking about what is your typical mV spread in leaf spy? Mine is 12-18mV & perhaps if yours is higher then that may explain since presumably a greater mV spread would indicate less total capacity since the lowest mV cells obfuscates the capacity difference of the higher mV cells.
 
HerdingElectrons said:
danrjones said:
How is our AHr the same but different SOH?

The short answer is I have no idea.

Thinking about what is your typical mV spread in leaf spy? Mine is 12-18mV & perhaps if yours is higher then that may explain since presumably a greater mV spread would indicate less total capacity since the lowest mV cells obfuscates the capacity difference of the higher mV cells.
12-18mV seems like a large spread. I don't check mine frequently but usually is 2-3mV.
Are you seeing this fully charged? and allow the charging to complete & shut off through it's rebalancing routine?
 
rogersleaf said:
HerdingElectrons said:
Thinking about what is your typical mV spread in leaf spy? Mine is 12-18mV & perhaps if yours is higher then that may explain since presumably a greater mV spread would indicate less total capacity since the lowest mV cells obfuscates the capacity difference of the higher mV cells.
12-18mV seems like a large spread. I don't check mine frequently but usually is 2-3mV.
Are you seeing this fully charged? and allow the charging to complete & shut off through it's rebalancing routine?
I often see spreads up to 20mV and hardly ever see them under 5mV...so I think he's fine.
 
Finally charged my 40kWh pack to 100%, so here are some readings:

  • GIDs = 480
  • Pack voltage = 403
  • Ahr = 110
  • Hx = 101
  • SOH = 95
 
rogersleaf said:
HerdingElectrons said:
danrjones said:
How is our AHr the same but different SOH?

The short answer is I have no idea.

Thinking about what is your typical mV spread in leaf spy? Mine is 12-18mV & perhaps if yours is higher then that may explain since presumably a greater mV spread would indicate less total capacity since the lowest mV cells obfuscates the capacity difference of the higher mV cells.
12-18mV seems like a large spread. I don't check mine frequently but usually is 2-3mV.
Are you seeing this fully charged? and allow the charging to complete & shut off through it's rebalancing routine?

Well, that is unusual...
 
danrjones said:
Latest stats for today:

SOH: 87.23
AMPhr: 100.7
Hx: 102.26

10,059 miles

I should be close to my next three month update, if there is one.

Finished my 3 month update.
It was small, but at least it was up this time.

Sitting at:

SOH: 87.90
AMPHr: 101.47
Hx: 102.33
 
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