User avatar
Stanton
Forum Supporter
Posts: 2151
Joined: Thu Feb 03, 2011 10:56 am
Delivery Date: 01 Sep 2011
Leaf Number: 7458
Location: Plano, TX
Contact: Website Twitter

Re: Gid Vs SOC and Cell Balance Issue

Tue Jul 26, 2016 1:39 pm

Vaggeto wrote:
Stanton wrote:
Nubo wrote: Do you use an end-timer? I'm not sure if that allows a full cell-balance, especially if you use the car shortly after the end-time. Maybe someone else can clarify.
That is a good point and basically true: if you really want to give the pack a chance to balance, you need to charge to 100% without a timer and sit for several hours (I think as many as 6).
Does this apply even though I use both a start and end time? My Leaf always charges instantly at 8PM and never waits to finish charging by a specific end time. It usually sits around 8-9 hours at a full charge before being driven.

Thanks,
John
My understanding is: yes, you need to run a 100% charge cycle without timers (use the bypass button). And let it set. Of course, there's no guarantee it will balance, but these are the necessary conditions to allow it.
2011 Blue Ocean SV w/floor mats & window tint
12v LiFePO4 battery & FIAMM 74100 horns
Wet Okole seat covers (front)
Tor's low-power heater mod
2013 sun visor
3G modem upgrade
L2 EVSE Upgrade
Battery Pack replaced (Rev E) @51 months and 41k miles

GerryAZ
Gold Member
Posts: 2289
Joined: Mon Nov 22, 2010 6:47 pm
Delivery Date: 12 Jun 2011
Location: Phoenix, AZ

Re: Gid Vs SOC and Cell Balance Issue

Tue Jul 26, 2016 9:12 pm

Stanton wrote:
Vaggeto wrote:
Stanton wrote:
That is a good point and basically true: if you really want to give the pack a chance to balance, you need to charge to 100% without a timer and sit for several hours (I think as many as 6).
Does this apply even though I use both a start and end time? My Leaf always charges instantly at 8PM and never waits to finish charging by a specific end time. It usually sits around 8-9 hours at a full charge before being driven.

Thanks,
John
My understanding is: yes, you need to run a 100% charge cycle without timers (use the bypass button). And let it set. Of course, there's no guarantee it will balance, but these are the necessary conditions to allow it.
John's start and end timer settings for his free power window are certainly sufficient to allow Leaf's LBC and onboard charger to charge to 100% and to balance the cells. I have start and end timers set for 9:10 pm to 8:50 am (9:00 pm to 9:00 am with 10 minutes to allow for differences between Leaf's clock and meter's clock) for off-peak charging, but usually plug in after 9:10 pm and unplug before 7:00 am. My car usually finishes charging (from very low battery warning) in 4 hours including cell balancing so John's car has plenty of time for cell balancing. The Leaf Spy screen shots clearly indicate he has a couple of somewhat weak cell pairs. They will likely get worse as time goes on.

Gerry
Gerry
Silver LEAF 2011 SL rear ended (totaled) by in-attentive driver 1/4/2015 at 50,422 miles
Silver LEAF 2015 SL purchased 2/7/2015; traded 8/10/2019 at 82,436 miles
White LEAF 2019 SL+ purchased 8/10/2019

TimLee
Posts: 2811
Joined: Thu Jan 20, 2011 9:40 am
Delivery Date: 17 May 2011
Leaf Number: 2026
Location: Chattanooga, TN

Re: Gid Vs SOC and Cell Balance Issue

Wed Jul 27, 2016 7:01 am

GerryAZ wrote:The Leaf Spy screen shots clearly indicate he has a couple of somewhat weak cell pairs. They will likely get worse as time goes on.

Gerry
They could improve.

My first CVLI via LEAF Spy Pro at about two and a half years old and two capacity bars lost had eight cell pairs showing weak.

After quite a bit of deep discharge down to high voltage disconnect and then recharging to 100% most went away.
And that was before Jim revised LEAF Spy Pro to require a much bigger error than the original 2011 manual CVLI test procedure.

The eight are still usually the weakest cells, but with deep discharge and rebalancing they now stay much closer.

Tim Lee
Chattanooga, TN

Man. Date: 03/10/11, VIN # 2026
Delivered 05-17-2011
Blue Ocean, 2011 SL-eTec

Valdemar
Posts: 2628
Joined: Tue May 10, 2011 10:32 pm
Delivery Date: 09 Sep 2011
Location: Oak Park, CA

Re: Gid Vs SOC and Cell Balance Issue

Wed Jul 27, 2016 9:59 am

Given the accessible capacity of the pack is limited by the weakest cell (pair) I wonder how much range is lost if there are obvious outliers, even if they only pop up below the LBW.
'11 SL, totaled
-1CB@33k/21mo, -2CB@53k/33mo, -3CB@68k/41mo, -4CB(41.5AHr)@79k/49mo, -5CB(38.85AHr)@87.5k/54mo
-0CB(66.14AHr)@87.5k/54mo (BBB), -1CB(53.92Ahr)@140k/29mo,
51.1AHr, SOH 80%, 150k miles

9kW Solar

DaveinOlyWA
Posts: 14206
Joined: Sat Apr 24, 2010 7:43 pm
Delivery Date: 16 Nov 2019
Leaf Number: 319862
Location: Olympia, WA
Contact: Website

Re: Gid Vs SOC and Cell Balance Issue

Fri Jul 29, 2016 5:26 am

Vaggeto wrote:
DaveinOlyWA wrote:run it down to around 80% and post a screen shot
Alright... you can find a new series of screenshots at the link below.

http://imgur.com/a/O70cG

I started at ~75% and then another at about 45% and then took some others as I got lower all the way until I turtled.

The variance looked until half full but then it really started to grow. I also got one at exactly 3.712.

Do these provide any other insight? it's interesting that at about 11.7% it highlights the weak cells but at 3.9% turtle it says all cells are okay.

Do these provide any other insight?

Thanks again for your time and knowledge. It's appreciated!
your variances are looking pretty normal here. did you take these screen shots

right after driving?

while driving?

several hours after driving?
2011 SL; 44,598 mi, 87% SOH. 2013 S; 44,840 mi, 91% SOH. 2016 S30; 29,413 mi, 99% SOH. 2018 S; 25,185 mi, SOH 92.23%. 2019 S Plus; 412 mi, 99.72% SOH
My Blog; http://daveinolywa.blogspot.com" onclick="window.open(this.href);return false;

Vaggeto
Posts: 14
Joined: Sat Mar 02, 2013 10:19 pm

Re: Gid Vs SOC and Cell Balance Issue

Fri Jul 29, 2016 8:34 am

DaveinOlyWA wrote:
Vaggeto wrote:
DaveinOlyWA wrote:run it down to around 80% and post a screen shot
Alright... you can find a new series of screenshots at the link below.

http://imgur.com/a/O70cG

I started at ~75% and then another at about 45% and then took some others as I got lower all the way until I turtled.

The variance looked until half full but then it really started to grow. I also got one at exactly 3.712.

Do these provide any other insight? it's interesting that at about 11.7% it highlights the weak cells but at 3.9% turtle it says all cells are okay.

Do these provide any other insight?

Thanks again for your time and knowledge. It's appreciated!
your variances are looking pretty normal here. did you take these screen shots

right after driving?

while driving?

several hours after driving?
These screenshots were primarily while driving or for the last one, right after driving.

DaveinOlyWA
Posts: 14206
Joined: Sat Apr 24, 2010 7:43 pm
Delivery Date: 16 Nov 2019
Leaf Number: 319862
Location: Olympia, WA
Contact: Website

Re: Gid Vs SOC and Cell Balance Issue

Fri Jul 29, 2016 7:57 pm

Vaggeto wrote:
DaveinOlyWA wrote:
Vaggeto wrote:
Alright... you can find a new series of screenshots at the link below.

http://imgur.com/a/O70cG

I started at ~75% and then another at about 45% and then took some others as I got lower all the way until I turtled.

The variance looked until half full but then it really started to grow. I also got one at exactly 3.712.

Do these provide any other insight? it's interesting that at about 11.7% it highlights the weak cells but at 3.9% turtle it says all cells are okay.

Do these provide any other insight?

Thanks again for your time and knowledge. It's appreciated!
your variances are looking pretty normal here. did you take these screen shots

right after driving?

while driving?

several hours after driving?
These screenshots were primarily while driving or for the last one, right after driving.
well then, I have to say your pack appears to be in fairly good shape. my delta stays under 20-25 mV until I hit the teens on SOC. This is where I see wild variances quite regularly. I do see up to 400mV and more sometimes. As far as the weak cells? I would keep a close eye on them paying attention to which # cell is having the most issues. the real issue starts when you have range issues so its hard to say what I would do in your case but if it were me, I would literally have no choice but to take it in for a cell check. I need all the range I can get plus some.
2011 SL; 44,598 mi, 87% SOH. 2013 S; 44,840 mi, 91% SOH. 2016 S30; 29,413 mi, 99% SOH. 2018 S; 25,185 mi, SOH 92.23%. 2019 S Plus; 412 mi, 99.72% SOH
My Blog; http://daveinolywa.blogspot.com" onclick="window.open(this.href);return false;

jmk
Posts: 9
Joined: Thu Oct 22, 2015 3:48 am
Delivery Date: 06 Jun 2012

Re: Gid Vs SOC and Cell Balance Issue

Sun Jul 31, 2016 4:06 am

DaveinOlyWA wrote: well then, I have to say your pack appears to be in fairly good shape.
Speaking of which, does anyone know how the SOH is calculated exactly? My pack seems to give delta of 6mV after balancing and overall stays looking very nice under all conditions. Yet the SOH is reading is 87% and I'm not sure I see any considerable difference in range to new. Car is 2012 SL with 35 000km in it.

TimLee
Posts: 2811
Joined: Thu Jan 20, 2011 9:40 am
Delivery Date: 17 May 2011
Leaf Number: 2026
Location: Chattanooga, TN

Re: Gid Vs SOC and Cell Balance Issue

Mon Aug 01, 2016 3:12 pm

jmk wrote:
DaveinOlyWA wrote: well then, I have to say your pack appears to be in fairly good shape.
Speaking of which, does anyone know how the SOH is calculated exactly? My pack seems to give delta of 6mV after balancing and overall stays looking very nice under all conditions. Yet the SOH is reading is 87% and I'm not sure I see any considerable difference in range to new. Car is 2012 SL with 35 000km in it.
Nissan engineers know but they haven't told anyone outside Nissan the secret.

Even in Finland a 2012 has probably lost 13% capacity just due to time.

Tim Lee
Chattanooga, TN

Man. Date: 03/10/11, VIN # 2026
Delivered 05-17-2011
Blue Ocean, 2011 SL-eTec

jmk
Posts: 9
Joined: Thu Oct 22, 2015 3:48 am
Delivery Date: 06 Jun 2012

Re: Gid Vs SOC and Cell Balance Issue

Thu Aug 04, 2016 1:22 am

TimLee wrote: Nissan engineers know but they haven't told anyone outside Nissan the secret.

Even in Finland a 2012 has probably lost 13% capacity just due to time.
Maybe, but I hear funny stories from people here that say how SOH keeps changing. Some say 91% reading jumped to 99% after balancing and quick charging. Also in my case I can't really confirm any actual capacity loss, car goes quite happily 150km on single charge and I'm not sure it has ever done any more than that. Drive very very carefully and I think that 160-170km is doable. Yet 13% should be noticeable already..

Return to “Range / Efficiency / Carwings”