The 40KWH Battery Topic

[WetEV]

Ok, got the new SOH, its 95.64, 0.07 lower, than 8 hours before... either the BMS is dead, or the battery cells are dead. Since I have issues with epedal regen also, I think the BMS is buggy somewhere. Now I need to wait until it dies so I get a replacement...

Past capacity estimates have been about +-3% or worse accuracy. 1% isn't meaningful. 0.1% is even less meaningful.

[kovadam]

Now I am at 95.22. Basically every time I turn off the car, then on it goes down by 0.07%...

[WetEV]

Now I am at 95.22. Basically every time I turn off the car, then on it goes down by 0.07%...

Which doesn't mean that capacity has decreased by 0.07%.

An estimation isn't the same as the real thing.

[kovadam]

Yeah, thats right. Will see if the drop stops,and will also see if the next time I charge to 100%, how many GIDs and kWh I get....

[WetEV]

Yeah, thats right. Will see if the drop stops,and will also see if the next time I charge to 100%, how many GIDs and kWh I get....

GIDs are also estimated. As are kWh as reported by the car.

Discharge to 20% or so, and do a measured charge test with a metered EVSE. Do it with the same battery temperature each time.

[jlv]

Ok, got the new SOH, its 95.64, 0.07 lower, than 8 hours before

You can't make meaningful comparisons of SOH changes unless you do so over the order of months. Trying to compare changes to the value over hours is just noise.

[kovadam]

Ok, got the new SOH, its 95.64, 0.07 lower, than 8 hours before

You can't make meaningful comparisons of SOH changes unless you do so over the order of months. Trying to compare changes to the value over hours is just noise.

I made the comparison over months, this is why it was very-very strange, that it dropped 1.5% within a few days, and about 0.7% within hours, since from the beginning it was declining quite slowly and reached 2.5% drop in 6 months, then 1.5% drop in just 3 days...

[DaveinOlyWA]

In the previous 3 LEAFs, I saw the opposite where it maintained "new" status for probably (don't have specific stats on the 2011) the first 6 months or more. The 2016 went 14 months and over 29,000 miles at 100% SOH and 99.64% of its original ahr

Yes, but you do many QCs, which increase the estimated SOH.

Several experiments have shown usage and not method of charging has the greatest effect. Realize NCTC for me lasted only 90 days on my 2013 so it was charged at home on level 2 about 90% of the time. It did the same; had like new stats for first 8 months and 10,500 miles

[danrjones]

In the previous 3 LEAFs, I saw the opposite where it maintained "new" status for probably (don't have specific stats on the 2011) the first 6 months or more. The 2016 went 14 months and over 29,000 miles at 100% SOH and 99.64% of its original ahr

Yes, but you do many QCs, which increase the estimated SOH.

Several experiments have shown usage and not method of charging has the greatest effect. Realize NCTC for me lasted only 90 days on my 2013 so it was charged at home on level 2 about 90% of the time. It did the same; had like new stats for first 8 months and 10,500 miles

For the newer folks following along, what is NCTC?

[goldbrick]

NCTC = no charge ($) to charge. I think it was promotion from Nissan that allowed free public charging for a period of time.