2016-2017 model year 30 kWh bar losers and capacity losses

[SageBrush]

Right. And the SOH and Ahrs will most likely return to the pre-reset values. Again, Nissan just basically reduced their liability by changing
the slope of the rate at which bars drop over the warranty period.

Do you mean that the 4rth bar will drop at an even lower battery capacity/range ?

[alozzy]

@webeleafowners Nothing has physically changed with the SOH (state of health) of the battery pack, it's just that the algorithms that the BMS uses have been changed as apparently they were flawed.

What's contentious is that Nissan has exclusive control of the algorithms that determine whether an owner qualifies for a replacement battery under warranty. They have just changed that algorithm, claiming that the reported degradation that people were seeing (via the capacity bars and via Leaf Spy metrics) was flawed.

As part of the procedure for applying the software update, the BMS health metrics has been reset. So, for a period of weeks/months the BMS has to learn the actual state of the battery health based on the new algorithms in the software.

So, anyone who has had the update applied to their LEAF will now see "spoofed" metrics in Leaf Spy and any capacity bar losses will likewise be reset to a full 12 bars.

Understand that the only means a LEAF owner has to gauge battery health is via the capacity bars, or via Leaf Spy metrics - both of which rely on the BMS - the same component that is now running the new software.

There really is no way for an owner to independently measure the health of the pack, other than doing a driving test to estimate the range and, along with the efficiency measurement, extrapolating the pack capacity based on those empirical measurements. But even the reported efficiency (in miles/kWh) is derived from the BMS.

Thus the skepticism...

[edatoakrun]

...There really is no way for an owner to independently measure the health of the pack, other than doing a driving test to estimate the range and, along with the efficiency measurement, extrapolating the pack capacity based on those empirical measurements...

Actually, measuring the kWh accepted on recharge from "100%" to stop (or at least turtle) using an accurate external meter is a second, more accurate method.

...But even the reported efficiency (in miles/kWh) is derived from the BMS...

No, in 2011-12 LEAFs the kWh used, as displayed on the dash, nav screen and in CW/NC reports is NOT the same value as the LBC's (BMS's) far-less-accurate estimates of kWh remaining in the pack, and I expect that's probably also the case for all LEAFs to date.

Which allows a third (and easiest) method of calculating the LBC error and actual pack capacity in "24 kWh" packs (and, as yet to be proven, also for "30 kWh" packs?) by finding the corresponding constant error in your LBC's energy calculations, by comparing a large sample of the total kWh used as reported by CW/NC against the data form the corresponding metered recharges, from your regular driving and charging experience.

2016 30 kWh Battery data

...

I also noticed that the car displayed 3.5 mi/kWh avg...

First, use mapping software to find your odometer error in your CW/NC miles driven reports to correct the mi in 3.5 mi/kWh.

Then, use your expected discharge/recharge efficiency to correct the kWh used error, as reported by CW/NC in 3.5 mi/kWh.

If your 30 "kWh" LEAF has the same error in kWH use reported on the Dash/NaV screen and CW/NC as do 2011 LEAFs, then you could calculate capacity loss from this consistent error, without having to do full discharge/charge tests.

My 2011's LBC currently reports ~36% capacity loss, but the kWh use report error is close to a consistent 12%, meaning each nominal kWH reported on my dash/nav screen and CW/NC, actually contains ~1,120 WH, and my available pack capacity is now ~24 % below spec...

http://www.mynissanleaf.com/viewtopic.p ... 59#p530459

If-and-when all three methods give you ~the same results (which has the case for my pack for many years now) I think you should be fairly confident of your actual available pack capacity.

[webeleafowners]

@webeleafowners Nothing has physically changed with the SOH (state of health) of the battery pack, it's just that the algorithms that the BMS uses have been changed as apparently they were flawed.

What's contentious is that Nissan has exclusive control of the algorithms that determine whether an owner qualifies for a replacement battery under warranty. They have just changed that algorithm, claiming that the reported degradation that people were seeing (via the capacity bars and via Leaf Spy metrics) was flawed.

As part of the procedure for applying the software update, the BMS health metrics has been reset. So, for a period of weeks/months the BMS has to learn the actual state of the battery health based on the new algorithms in the software.

So, anyone who has had the update applied to their LEAF will now see "spoofed" metrics in Leaf Spy and any capacity bar losses will likewise be reset to a full 12 bars.

Understand that the only means a LEAF owner has to gauge battery health is via the capacity bars, or via Leaf Spy metrics - both of which rely on the BMS - the same component that is now running the new software.

There really is no way for an owner to independently measure the health of the pack, other than doing a driving test to estimate the range and, along with the efficiency measurement, extrapolating the pack capacity based on those empirical measurements. But even the reported efficiency (in miles
/kWh) is derived from the BMS.

Thus the skepticism...

Ahhh. That makes it clearer. I kinda understand most of that.

I’ll remain optimistic and report what I can after the update, which is tomorrow at 8 o’clock.

[lorenfb]

Right. And the SOH and Ahrs will most likely return to the pre-reset values. Again, Nissan just basically reduced their liability by changing
the slope of the rate at which bars drop over the warranty period.

Do you mean that the 4rth bar will drop at an even lower battery capacity/range ?

Yes. And how about if bars drop based on time now, e.g. a bar every two years. Now that would surely reduce battery liabilities, right?
Using loss of bars is such an arbitrary measure that Nissan can have it represent anything. We'll have to see what happens over time.

[alozzy]

@edatoakrun

Actually, measuring the kWh accepted on recharge from "100%" to stop (or at least turtle) using an accurate external meter is a second, more accurate method.

Not really, there are losses.

No, in 2011-12 LEAFs the kWh used, as displayed on the dash, nav screen and in CW/NC reports is NOT the same value as the LBC's (BMS's) far-less-accurate estimates of kWh remaining in the pack, and I expect that's probably also the case for all LEAFs to date

I was talking about efficiency - miles/kWh

[edatoakrun]

edatoakrun:

Actually, measuring the kWh accepted on recharge from "100%" to stop (or at least turtle) using an accurate external meter is a second, more accurate method.

Not really, there are losses...

Of course, but since those losses are known (much more precisely for the "24 kWh" packs, than the "30 kWh" packs, unfortunately) you can use the metered kWh supplied, to find the error in the kWh used report, as I pointed out in the other thread I linked in my previous comment.

Range tests, on the other hand, are very difficult to conduct accurately, since there are many variables that cannot be easily controlled.

edatoakrun:

No, in 2011-12 LEAFs the kWh used, as displayed on the dash, nav screen and in CW/NC reports is NOT the same value as the LBC's (BMS's) far-less-accurate estimates of kWh remaining in the pack, and I expect that's probably also the case for all LEAFs to date

I was talking about efficiency - miles/kWh

Yes, but miles/kWh will be corrupted if either factor is.

And, if you do learn how to do a (fairly) accurate range test, I expect it will be obvious to you that LBC kWh values are so FUBAR that they are best disregarded entirely, if you are trying to get an accurate estimate of your pack capacity.

After all, if the LEAF's LBC kWh values were correct, this entire thread, and the hundreds of threads and tens of thousands of posts preceding on the same subject, would have been unnecessary...

[SageBrush]

Of course, but since those losses are known (much more precisely for the "24 kWh" packs, than the "30 kWh" packs, unfortunately) you can use the metered kWh supplied, to find the error in the kWh used report, as I pointed out in the other thread I linked in my previous comment.

There is a fair amount of variation in charging efficiency, and not just SoC related. Battery temperature matters too.
That said, I'm tempted to say that charging is the best casual test owners have. The meter to OBC losses can be circumvented by using the charging graph presented by LeafSpy. I'll presume that the LEAF can at least measure the Amps and Volts accurately during charging.

[SageBrush]

Right. And the SOH and Ahrs will most likely return to the pre-reset values. Again, Nissan just basically reduced their liability by changing
the slope of the rate at which bars drop over the warranty period.

Do you mean that the 4rth bar will drop at an even lower battery capacity/range ?

Yes.

I take it then that you doubt Nissan's pitch that they have simply corrected a reporting bug ?
As is, the 4rth bar was dropping around 60 - 65% of new battery capacity if you believe the LeafSpy Ahr readings.

[dwl]

@edatoakrun

Actually, measuring the kWh accepted on recharge from "100%" to stop (or at least turtle) using an accurate external meter is a second, more accurate method.

Not really, there are losses.

The complance documents from Nissan https://iaspub.epa.gov/otaqpub/display_ ... 671&flag=1 that state Recharge Energy Event value of 31.78kWh at 240V should be expected to take these losses into account. This would seem a reasonable way to assess relative SoH provided done at normal ambient temperatures around 25°C.