dwl
Posts: 107
Joined: Tue Jan 05, 2016 5:06 pm
Delivery Date: 08 Jan 2016
Leaf Number: 112097
Location: New Zealand

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

Wed Jul 25, 2018 3:23 am

jbuntz wrote:
dwl wrote:
jbuntz wrote: VLB is at the same number of GIDs but SOC in LeafSpy is much higher. At turtle SOC still reported 5.7%. Prior to update SOC at turtle was 0.0%

Useful info. Prior to the update did you notice when SOC first reached 0% (how many GIDs)?
Prior to update up to 6 GID = 0% 9 GID =1.3% 41 GID = 11.5%. Now 5 GID = 5.7 and 5.4 %

These results are similar to what has been seen on the dyno prior to update. In one case the car reached very low SoC and about 9 GIDs and kept going for over 15 mins at a constant C/3 load (27A, probably enough for 45mph). On average the car was dwelling for about 30-40 seconds per GID but at 9 and 8 GIDs dwelt for about 7 mins on each of those GIDs before moving again. Calculation wrong.

Your earlier pre-update post of many miles from LBW to turtle is also very useful. The update appears to have fixed this issue and your experience over time will be of great interest - thanks for sharing.

An update has just been released in New Zealand on our perspective of the update https://flipthefleet.org/2018/30-kwh-nissan-leaf-firmware-update-to-correct-capacity-reporting/
2014 S - 6000 km Jan 2016; 45000 km May 2017 95% SoH; 68,000 km Mar 2018 90% SoH

marcelg
Posts: 21
Joined: Wed Sep 06, 2017 6:04 am
Delivery Date: 06 Sep 2017
Leaf Number: 307144
Location: Ottawa, ON
Contact: Website Twitter

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

Wed Jul 25, 2018 5:58 am

dwl wrote:
jbuntz wrote:
dwl wrote:Useful info. Prior to the update did you notice when SOC first reached 0% (how many GIDs)?
Prior to update up to 6 GID = 0% 9 GID =1.3% 41 GID = 11.5%. Now 5 GID = 5.7 and 5.4 %

These results are similar to what has been seen on the dyno prior to update. In one case the car reached very low SoC and about 9 GIDs and kept going for over 15 mins at a constant C/3 load (27A, probably enough for 45mph). On average the car was dwelling for about 30-40 seconds per GID but at 9 and 8 GIDs dwelt for about 7 mins on each of those GIDs before moving again. Calculation wrong.

Your earlier pre-update post of many miles from LBW to turtle is also very useful. The update appears to have fixed this issue and your experience over time will be of great interest - thanks for sharing.

An update has just been released in New Zealand on our perspective of the update https://flipthefleet.org/2018/30-kwh-nissan-leaf-firmware-update-to-correct-capacity-reporting/


Thanks for the update.

My 2017 Leaf S just got the software update. I've had it since September 2017. It went from SOH 86% in the winter at 2500km, when I first got LeafSpy, to SOH 89% in the spring after recalibrating (running down to turtle, then charging to 100%), to SOH 95% after getting the update at about 7000 km.

I haven't tried any range tests yet, but in the winter it did seem like I got a lot more km out of 10% of the battery at the top end then I did at the bottom end. Eg. from 90%-80% I would get 12km, but from 40%-30% I would get 8km. It felt like the GOM and the % remaining would start going down faster as the battery got lower even if the driving speed was constant.

WetEV
Posts: 2371
Joined: Fri May 04, 2012 8:25 am
Delivery Date: 16 Feb 2014
Location: Near Seattle, WA

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

Wed Jul 25, 2018 7:30 am

lorenfb wrote:Amazing what one can do by changing a few binary numbers, right?


Why not do a range test and see what the reality is, rather than assuming Nissan is wrong?
WetEV
#49
Most everything around here is wet during the rainy season. And the rainy season is long.
2012 Leaf SL Red (Totaled)
2014 Leaf SL Red

lorenfb
Posts: 1845
Joined: Tue Dec 17, 2013 10:53 pm
Delivery Date: 22 Nov 2013
Leaf Number: 416635
Location: SoCal

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

Wed Jul 25, 2018 9:34 am

WetEV wrote:
lorenfb wrote:Amazing what one can do by changing a few binary numbers, right?


Why not do a range test and see what the reality is, rather than assuming Nissan is wrong?


I don't have a 30 kWh Leaf. We'll see over time what the actual/true result of the firmware update is.
But isn't strange that the BMS firmware for my 24 kWh Leaf hasn't "over estimated" SOH degradation?
Did Nissan use another engineering team to write the BMS code for the 30 kWh versus the 24 kWh Leaf,
which recently required an update that's coincidental with recent increased battery warranty claims?
Leaf SL MY 9/13: 70K miles, 49 Ahrs, 5.1 miles/kWh (average), Hx=70, SOH=78, L2 charges to 100% > 1000, max battery temp < 95F (35C), min discharge point > 20 Ahrs

WetEV
Posts: 2371
Joined: Fri May 04, 2012 8:25 am
Delivery Date: 16 Feb 2014
Location: Near Seattle, WA

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

Wed Jul 25, 2018 9:53 am

lorenfb wrote:But isn't strange that the BMS firmware for my 24 kWh Leaf hasn't "over estimated" SOH degradation?
Did Nissan use another engineering team to write the BMS code for the 30 kWh versus the 24 kWh Leaf,
which recently required an update that's coincidental with recent increased battery warranty claims?


Nissan's claim is that they tested the batteries replaced under warranty, and these packs were not degraded enough to require replacement.

Have you any measurements that show otherwise?

If not, why not?

If not, why the allegations?

I've written a lot of code in my life, which means I written a lot of bugs. I can think of a dozen ways to write a bug that would make the BMS code might overestimate degradation of a larger pack. Why? Because I've seen such bugs, both other peoples and my own.
WetEV
#49
Most everything around here is wet during the rainy season. And the rainy season is long.
2012 Leaf SL Red (Totaled)
2014 Leaf SL Red

SageBrush
Posts: 2943
Joined: Sun Mar 06, 2011 2:28 am
Delivery Date: 13 Feb 2017
Location: Colorado

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

Wed Jul 25, 2018 10:05 am

WetEV wrote:
lorenfb wrote:Amazing what one can do by changing a few binary numbers, right?


Why not do a range test and see what the reality is,

Range tests are too susceptible to driving and environmental variables.

Charging up is a much better test, albeit with perhaps a 5% variation in charging losses even if the test is consistent with L1 or L2 charging. I'm coming around to the idea that the update changed the LB and VLB thresholds. Since people use VLB as a practical range limit, the update has merit so long as it does not drag the battery down into SoC levels at VLB that will accelerate degradation.

Personally, I like the idea of minimum cell 3.3 V as a VLB threshold, and some user experiences report that trigger is now much lower ... in the 2.5 - 2.6 V range if memory serves. If true, this update is not going to end well. A Tesla owner with a 85 kWh Model S monitored cell voltages via canbus and found that the car shut down when a cell hit ~ 2.97 V.
2013 LEAF 'S' Model with QC & rear-view camera
Bought off-lease Jan 2017 from N. California
Car is now enjoying an easy life in Colorado
03/2018: 58 Ahr, 28k miles
11/2018: 56.16 Ahr, 30k miles
-----
2018 Tesla Model 3 LR, Delivered 6/2018

jbuntz
Posts: 139
Joined: Thu Dec 08, 2016 5:41 am
Delivery Date: 17 Dec 2016
Leaf Number: 303765
Location: New Braunfels, TX

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

Wed Jul 25, 2018 10:42 am

dwl wrote:
jbuntz wrote:
dwl wrote:Useful info. Prior to the update did you notice when SOC first reached 0% (how many GIDs)?
Prior to update up to 6 GID = 0% 9 GID =1.3% 41 GID = 11.5%. Now 5 GID = 5.7 and 5.4 %

These results are similar to what has been seen on the dyno prior to update. In one case the car reached very low SoC and about 9 GIDs and kept going for over 15 mins at a constant C/3 load (27A, probably enough for 45mph). On average the car was dwelling for about 30-40 seconds per GID but at 9 and 8 GIDs dwelt for about 7 mins on each of those GIDs before moving again. Calculation wrong.

Your earlier pre-update post of many miles from LBW to turtle is also very useful. The update appears to have fixed this issue and your experience over time will be of great interest - thanks for sharing.

An update has just been released in New Zealand on our perspective of the update https://flipthefleet.org/2018/30-kwh-nissan-leaf-firmware-update-to-correct-capacity-reporting/

This report is the best explanation of the update I have read and correlates with my experience. Unfortunately after the update I am still at 82% SOH and falling. No longer 8 bars but still heading in that direction. I should be due a new battery by this time next year.
Mfg 11/15 Del 12/16 TX 2016 SL 30kWh,
Date Bar MI GID Ahr SOH
05/17 12 05175 324 70.75 89
08/17 11 09245 282 61.68 77
10/17 10 12000 260 57.22 71
01/18 09 15329 244 53.72 68
06/20 08 21716 230 50.41 63
06/27 11 22047 296 66.01 83 Aftr Updt

SageBrush
Posts: 2943
Joined: Sun Mar 06, 2011 2:28 am
Delivery Date: 13 Feb 2017
Location: Colorado

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

Wed Jul 25, 2018 11:23 am

Awesome report from New Zealand.
I'd like to recommend the update to a 30 kwh LEAF owning friend if I can confirm that the lowest cell voltage threshold for VLB has not been lowered into accelerated degradation territory.
2013 LEAF 'S' Model with QC & rear-view camera
Bought off-lease Jan 2017 from N. California
Car is now enjoying an easy life in Colorado
03/2018: 58 Ahr, 28k miles
11/2018: 56.16 Ahr, 30k miles
-----
2018 Tesla Model 3 LR, Delivered 6/2018

dwl
Posts: 107
Joined: Tue Jan 05, 2016 5:06 pm
Delivery Date: 08 Jan 2016
Leaf Number: 112097
Location: New Zealand

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

Wed Jul 25, 2018 1:02 pm

SageBrush wrote:
WetEV wrote:
lorenfb wrote:Amazing what one can do by changing a few binary numbers, right?
Why not do a range test and see what the reality is,
Range tests are too susceptible to driving and environmental variables.

Charging up is a much better test, albeit with perhaps a 5% variation in charging losses even if the test is consistent with L1 or L2 charging. I'm coming around to the idea that the update changed the LB and VLB thresholds. Since people use VLB as a practical range limit, the update has merit so long as it does not drag the battery down into SoC levels at VLB that will accelerate degradation.

I agree range tests can be variable which is why the tests here were dyno based with external current metering. Significant efforts were also made to temperature stabilise the battery (needed heating, cold here in New Zealand at the moment). The final answer is how much energy can the battery deliver when driving.

One of the dealers here uses the charge method to prove actual capacity and this result doesn’t change with the update. One friend who had dropped to 80% SOH on Leaf Spy had the check done and charge method showed around 88% SOH so a dealer could claim no fault. However as this issue affected LBW and VLBW levels it meant the effective range was reduced. This has been a useful wake up from Nissan that EVs have their own complexities.

Another issue is mentioned in a local forum - especially relevant if people don’t like letting their car go below LBW:
“I think something important has been left out of the conversation here. The patch doesn't just fix the perception of range, it also results in more of the battery being used between charges, and thus the battery being at a lower state of charge on average. If I can charge my car every 3 days instead of every 2 days, my average state of charge will be lower and my (real) battery degradation should be lower over time.

So not applying the patch could cause it to decline in capacity sooner than if you had the patch installed.

Some of the rapid degradation we have seen, even after the patch is applied is thus very real, and caused by people keeping their batteries at a higher state of charge than they knew.

This is probably a small effect, but noteworthy for those of us who have a choice around charging and want to keep the battery in top shape.“
2014 S - 6000 km Jan 2016; 45000 km May 2017 95% SoH; 68,000 km Mar 2018 90% SoH

SageBrush
Posts: 2943
Joined: Sun Mar 06, 2011 2:28 am
Delivery Date: 13 Feb 2017
Location: Colorado

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

Wed Jul 25, 2018 1:44 pm

^^ Regarding that dyno test, I'd like to know if the results change when a higher discharge rate is used, say 1 C.

Second, do you have an opinion or data on what minimum cell voltage is reached at VLB in these post-update packs ?
2013 LEAF 'S' Model with QC & rear-view camera
Bought off-lease Jan 2017 from N. California
Car is now enjoying an easy life in Colorado
03/2018: 58 Ahr, 28k miles
11/2018: 56.16 Ahr, 30k miles
-----
2018 Tesla Model 3 LR, Delivered 6/2018

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