dwl
Posts: 107
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Leaf Number: 112097
Location: New Zealand

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

Thu Jul 26, 2018 1:52 am

SageBrush wrote:^^ 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 ?

I managed to get a brief chat with the specialist and a test was done at 1C which did create a significant rise in temperature. I would expect slightly less capacity but didn’t get any data. By staying down at C/3, which is also a reference used by AESC, the temperature rise was only a few degrees and removes that as a variable.

Cell voltages were usually not taken down very low to turtle as the amount of energy on that last slope (e..g once under 2.9V per cell) is very little. These cars are owned by others and don’t want to stress the battery.
2014 S - 6000 km Jan 2016; 45000 km May 2017 95% SoH; 68,000 km Mar 2018 90% SoH

SageBrush
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Location: Colorado

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

Thu Jul 26, 2018 7:07 am

dwl wrote:Cell voltages were usually not taken down very low to turtle as the amount of energy on that last slope (e..g once under 2.9V per cell) is very little. These cars are owned by others and don’t want to stress the battery.

I'm asking about minimum cell voltage at VLB
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

WetEV
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Location: Near Seattle, WA

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

Thu Jul 26, 2018 9:32 am

SageBrush wrote:
dwl wrote:Cell voltages were usually not taken down very low to turtle as the amount of energy on that last slope (e..g once under 2.9V per cell) is very little. These cars are owned by others and don’t want to stress the battery.

I'm asking about minimum cell voltage at VLB


Sage is trying to find some reason to complain about the Leaf's battery.
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

Evoforce
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Location: Fountain Hills Arizona

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

Thu Jul 26, 2018 2:08 pm

Hopefully with the 2019 Leaf, there won't be a reason to complain about the battery. I am looking forward to that day.
*2011 Leaf 1 bought 2/28/15 @ 28,000ish mi 10 bar (8 bars @ 11/25/15 @ 37,453 ) (New lizard @ 39,275 mi @ 1/20/2016) Now 52,166 mi.
*Tesla Model S 61,000 mi
*2011 Leaf 2 bought 4/28/15 @ 24,000ish mi 12 bar (new lizard Dec. 2014 @ 22,273 mi) Now 35,485 mi

johnlocke
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Leaf Number: 300582

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

Thu Jul 26, 2018 6:39 pm

WetEV wrote:
SageBrush wrote:
dwl wrote:Cell voltages were usually not taken down very low to turtle as the amount of energy on that last slope (e..g once under 2.9V per cell) is very little. These cars are owned by others and don’t want to stress the battery.

I'm asking about minimum cell voltage at VLB


Sage is trying to find some reason to complain about the Leaf's battery.

OK, I ran my battery down to 13 GID's today. I couldn't get the value for VLB because I was going up a long grade and couldn't pull over to record it but I do have a value for VLBW (25 GIDS, 6%) 334 VDC (3.48 V/cell). 9% (32 GID's) was 336 VDC (3.50 V/cell) and 3%(13 GID's) was 330 VDC (3.44 V/cell). I didn't have any desire to find turtle so that's not included. Referring back to my notes for the original battery when new, I can see that the new battery is holding a higher voltage at low charge ( old battery was 317VDC at 3%) but that;s the only difference I see.

LeafSpy was reporting 9.5% SOC at the 13 GID mark. It normally reports 97.5% SOC at full charge (100% on the dash gauge and 363 GID's in LeafSpy). I honestly don't know how much further I could have driven it so It could gone another couple or three miles (13 GID's=1 KWH) or perhaps as much as another 10 miles (9.5%=2.85 KWH). I'm not that adventurous. I would be interested in what others come with in regards to the cell voltages.
2016 SV, New battery at 45K mi.
Jamul, CA
San Diego East County

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

Thu Jul 26, 2018 6:59 pm

johnlocke wrote:OK, I ran my battery down to 13 GID's today. I couldn't get the value for VLB because I was going up a long grade and couldn't pull over to record it but I do have a value for VLBW (25 GIDS, 6%) 334 VDC (3.48 V/cell). 9% (32 GID's) was 336 VDC (3.50 V/cell) and 3%(13 GID's) was 330 VDC (3.44 V/cell). I didn't have any desire to find turtle so that's not included. Referring back to my notes for the original battery when new, I can see that the new battery is holding a higher voltage at low charge ( old battery was 317VDC at 3%) but that;s the only difference I see.
I'm most interested in the lowest cell pair voltage, since that is the trigger for the VLB warning.

Thanks for sharing.
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
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Leaf Number: 112097
Location: New Zealand

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

Thu Jul 26, 2018 8:23 pm

SageBrush wrote:
johnlocke wrote:OK, I ran my battery down to 13 GID's today. I couldn't get the value for VLB because I was going up a long grade and couldn't pull over to record it but I do have a value for VLBW (25 GIDS, 6%) 334 VDC (3.48 V/cell). 9% (32 GID's) was 336 VDC (3.50 V/cell) and 3%(13 GID's) was 330 VDC (3.44 V/cell). I didn't have any desire to find turtle so that's not included. Referring back to my notes for the original battery when new, I can see that the new battery is holding a higher voltage at low charge ( old battery was 317VDC at 3%) but that;s the only difference I see.
I'm most interested in the lowest cell pair voltage, since that is the trigger for the VLB warning.

Thanks for sharing.

I believe the trigger for the warnings (except turtle) isn't voltage but GIDs with the change to 49 and 24 GIDs for LBW and VLBW respectively. These are samples from part of one test where coincidentally SOC dropped to 0% at VLBW - note the timestamps in h:mm and extended period around 8 and 9 GIDs - the current was set at 27A on an external meter:

Image

As the battery ages, the voltage at the knee may not change a lot but the Ah curve reduces the location of the knee on the time axis. Voltage could be used but using GIDs may be a key reason why the calculation is causing more range anxiety - the VLB and VLBW thresholds are higher than expected above available capacity.

Using the example of 336V, the dyno test result had VLBW (2kWh) coming on while the measured capacity at that point down to cutoff (bit before turtle) was actually 3.74kWh.
Last edited by dwl on Fri Jul 27, 2018 2:47 am, edited 1 time in total.
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

Thu Jul 26, 2018 8:56 pm

@dwl,
Very informative, and reassuring that the update is not going to harm the battery.

Thanks
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

Fri Jul 27, 2018 12:52 am

SageBrush wrote:@dwl,
Very informative, and reassuring that the update is not going to harm the battery.

Thanks

To clarify, the data above is pre update. The update seems a genuine fix for the reporting issues most obvious where the car kept running with GIDs stuck at 9 then 8. The update may be beneficial to the battery as on average it can probably be left with less actual charge to achieve the same reported range.
2014 S - 6000 km Jan 2016; 45000 km May 2017 95% SoH; 68,000 km Mar 2018 90% SoH

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

Fri Jul 27, 2018 5:32 am

dwl wrote:
SageBrush wrote:
johnlocke wrote:
I believe the trigger for the warnings (except turtle) isn't voltage but GIDs with the change to 49 and 24 GIDs for LBW and VLBW respectively.


Correct
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http://jpwhitenissanleaf.com
Blue SL-e, Res 4/22/10, Ord 3/29/11, Del 7/30/11
110,000 Miles.
Lost 5 Capacity bars
7/18/13 (29,206), 8/25/14 (51,728), 7/12/15 (71.108), 5/12/16 (88,362), 10/17/16 (96,532)
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