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Re: 2016 30 kWh Battery data

Posted: Tue Jun 19, 2018 5:57 am
by DaveinOlyWA
jbuntz wrote:Currently my stats are 50.44 Ah 63.46 SOH 60.59 Hx 21622 Odo 230Gid 4 bars down. Appmt for Tuesday to get tested for replacement.

I did a test yesterday drove 77 miles to 6 GIDs. 70 miles were at 70 mph and the rest at less than 30. LeafSpy reported 17660 Wh used .5kWh remains. I then charged to 100%. EVSE total input was 25 kWh. Input was at 6737 Watts. LeafSpy displays 5874 to battery 200 Aux.

At 90% charger efficiency that would add about 22.5 kWh. LeafSpy at 100% charge reports 17.8 kWh Remain.

There will be some loss between battery input and charge but this seems excessive. Maybe this is the bms reprogramming fix?

I also noticed that the car displayed 3.5 mi/kWh avg where LeafSpy showed 4.4 over the 77 mile trip. Or 22.65 vs 17.5 kWh used.

So what do you think the true capacity is and what are they going to tell me Tuesday?
Unless the power in is measured by something other than the LEAF (or LEAF Spy) then there is no guarantee that the numbers are accurate.

I would go to a public station like Chargepoint. They tell you at the end how much power was provided. See how the numbers compare to what LEAF Spy said you received.

Re: 2016 30 kWh Battery data

Posted: Tue Jun 19, 2018 10:39 am
by jbuntz
DaveinOlyWA wrote:
jbuntz wrote:Currently my stats are 50.44 Ah 63.46 SOH 60.59 Hx 21622 Odo 230Gid 4 bars down. Appmt for Tuesday to get tested for replacement.

I did a test yesterday drove 77 miles to 6 GIDs. 70 miles were at 70 mph and the rest at less than 30. LeafSpy reported 17660 Wh used .5kWh remains. I then charged to 100%. EVSE total input was 25 kWh. Input was at 6737 Watts. LeafSpy displays 5874 to battery 200 Aux.

At 90% charger efficiency that would add about 22.5 kWh. LeafSpy at 100% charge reports 17.8 kWh Remain.

There will be some loss between battery input and charge but this seems excessive. Maybe this is the bms reprogramming fix?

I also noticed that the car displayed 3.5 mi/kWh avg where LeafSpy showed 4.4 over the 77 mile trip. Or 22.65 vs 17.5 kWh used.

So what do you think the true capacity is and what are they going to tell me Tuesday?
Unless the power in is measured by something other than the LEAF (or LEAF Spy) then there is no guarantee that the numbers are accurate.

I would go to a public station like Chargepoint. They tell you at the end how much power was provided. See how the numbers compare to what LEAF Spy said you received.
My power meter is a cheap one I bought on eBay. It is hooked to the input side of my GE EVSE.
Yesterday I drove 46.6 mi according to NC. It took 14kWh to charge to 100%. Dash shows 3.7 kWh/mi. I measured the distance to work today. Dash 21.0 GPS 21.3

Re: 2016 30 kWh Battery data

Posted: Tue Jun 19, 2018 10:55 am
by SageBrush
jbuntz wrote: My power meter is a cheap one I bought on eBay. It is hooked to the input side of my GE EVSE.
Yesterday I drove 46.6 mi according to NC. It took 14kWh to charge to 100%. Dash shows 3.7 kWh/mi. I measured the distance to work today. Dash 21.0 GPS 21.3
Good data.
If charging losses are 12.5% then 14*0.875 = 12.25 into battery.
46.6/12.25 = 3.8 miles per kWh. The car miles/kWh meter is probably within display error.

Re: 2016 30 kWh Battery data

Posted: Tue Jun 19, 2018 12:38 pm
by edatoakrun
edatoakrun wrote: 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....
jbuntz wrote: ...My power meter is a cheap one I bought on eBay. It is hooked to the input side of my GE EVSE.
Yesterday I drove 46.6 mi according to NC. It took 14kWh to charge to 100%. Dash shows 3.7 kWh/mi. I measured the distance to work today. Dash 21.0 GPS 21.3
Not clear from that comment, is how far you actually drove?

Use google maps or equivalent to plot the actual distance of your trips as precisely as possible.

I'd suggest you might want to try to use two days of commuting (driving slightly slower, if required) to get to (or beyond) VLBW, on one charge.

You only need to do this one time (carefully) as once you find the odometer error on your dash, and the (different error?) on NC, they will both remain constant until you significantly alter your front tire circumference.

Since your kWh meter is of limited accuracy, this will also give you a larger energy sample to reduce the uncertainty in the next step:
edatoakrun wrote: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...
By using the NC daily kWh use report, or the rate simulation trip reports, you can access the kWh used (to the nearest 0.1 kWh) in your dash display directly, without having to deduce it from the less-accurately-displayed m/kWh on your dash.

Re: 2016 30 kWh Battery data

Posted: Sat Jun 23, 2018 1:25 pm
by dwl
In the related thread at http://www.mynissanleaf.com/viewtopic.p ... 08#p530808 @jbuntz has provided some valuable insights into what look like substantial reporting errors at low GIDs. That earlier post said:
jbuntz wrote:I did a full discharge test yesterday. Got it down to 9gids on LeafSpy 3.639v 349.62v pack voltage. The qc screen said it was starting at 3% LeafSpy 2.2% soc .7kWh 98° Battery. 100% Charge took 31 minutes. Started at 45kW ended at 20kW. Started ramp Dow at 15 minutes. Ending temp 120F. Charger reported 19.81kWh delivered. (19.81 + .7) / 31.78 = 65% of original capacity?

Also, I was sitting in the car with th ac on for 30 minutes so I should subtract .5kWh from the delivered amount.

This is before bms reset.
The following discussion has:
jbuntz wrote:At 9 gids the voltage spread was only 14mv. At 6 gids (turtle) it was 68mv 331v pack.
It was clarified that at 6 GIDs turtle light hadn't come on. There is further discussion about 4 GIDs last year being 282V pack voiltage so seems to be getting way out now. Any wisdom from others in this forum as to what kWh should still be in the pack with cell voltages above 3.4V would be welcomed. [EDIT] The voltages mentioned may be during charging so could be significant offsets due to Hx but still seems too low GIDs for the voltages.

Re: 2016 30 kWh Battery data

Posted: Sat Jun 23, 2018 3:10 pm
by DaveinOlyWA
Turtle is voltage controlled and GIDs is charge storage so there is no real way to correlate the two. I had turtle come on at 4 GIDs one time and 8 GIDs another on the same pack.

Re: 2016 30 kWh Battery data

Posted: Sat Jun 23, 2018 3:50 pm
by dwl
DaveinOlyWA wrote:Turtle is voltage controlled and GIDs is charge storage so there is no real way to correlate the two. I had turtle come on at 4 GIDs one time and 8 GIDs another on the same pack.
This makes sense. I believe the issue is the difference between reported GIDs (calculated capacity) and turtle (voltage based). It seems the GID calculation may be substantially wrong in some cars by multiple kWh resulting in under-reporting Ahr/SoH.

Re: 2016 30 kWh Battery data

Posted: Sat Jun 23, 2018 9:38 pm
by lorenfb
dwl wrote:
DaveinOlyWA wrote:Turtle is voltage controlled and GIDs is charge storage so there is no real way to correlate the two. I had turtle come on at 4 GIDs one time and 8 GIDs another on the same pack.
This makes sense. I believe the issue is the difference between reported GIDs (calculated capacity) and turtle (voltage based). It seems the GID calculation may be substantially wrong in some cars by multiple kWh resulting in under-reporting Ahr/SoH.
And your conclusion is; That possibly the 30 kWh battery degradation is on par with other Leaf batteries, and all that's needed is the BMS
firmware update to indicate such, right?

Re: 2016 30 kWh Battery data

Posted: Sun Jun 24, 2018 12:26 am
by dwl
lorenfb wrote:
dwl wrote:
DaveinOlyWA wrote:Turtle is voltage controlled and GIDs is charge storage so there is no real way to correlate the two. I had turtle come on at 4 GIDs one time and 8 GIDs another on the same pack.
This makes sense. I believe the issue is the difference between reported GIDs (calculated capacity) and turtle (voltage based). It seems the GID calculation may be substantially wrong in some cars by multiple kWh resulting in under-reporting Ahr/SoH.
And your conclusion is; That possibly the 30 kWh battery degradation is on par with other Leaf batteries, and all that's needed is the BMS firmware update to indicate such, right?
The underlying degradation isn't yet clear. In addition to significantly under-reporting, I am aware of some cars that are reporting higher than expected SoH (e..g close to 100% when over a year old) which have less measured capacity than indicated so they may drop with the update. I imagine the target, as in the owners manual, is around 80% SoH at 5 years. I think it is too early to say how they will track towards that even with the BMS update. For the 24kWh models we are sitting, on average, slightly better than 80% at 5 years here in New Zealand (temperate climate).

Re: 2016 30 kWh Battery data

Posted: Sun Jun 24, 2018 6:01 am
by DaveinOlyWA
lorenfb wrote:
dwl wrote:
DaveinOlyWA wrote:Turtle is voltage controlled and GIDs is charge storage so there is no real way to correlate the two. I had turtle come on at 4 GIDs one time and 8 GIDs another on the same pack.
This makes sense. I believe the issue is the difference between reported GIDs (calculated capacity) and turtle (voltage based). It seems the GID calculation may be substantially wrong in some cars by multiple kWh resulting in under-reporting Ahr/SoH.
And your conclusion is; That possibly the 30 kWh battery degradation is on par with other Leaf batteries, and all that's needed is the BMS
firmware update to indicate such, right?
well that is a leap over several other recommended observations.