WLJ
Posts: 16
Joined: Fri Jun 15, 2018 1:59 pm
Delivery Date: 15 May 2019
Leaf Number: 310396
Location: Kamuela, Hawaii

Wildly inaccurate battery %

Thu Aug 20, 2020 6:44 pm

My 2019 Leaf plus battery percentage decreases normally to about 70% then begins to plummet. On my most recent drive, I started at 86% and after driving 56 miles was indicating 22% remaining. Leaf Pro said I had 63% remaining, and I used that figure to calculate time needed to bring the battery to 85%. The charge indicator worked normally for the first year, but began giving me bogus information a couple of months ago. Has anyone else encountered this problem?

WLJ
Posts: 16
Joined: Fri Jun 15, 2018 1:59 pm
Delivery Date: 15 May 2019
Leaf Number: 310396
Location: Kamuela, Hawaii

Re: Wildly inaccurate battery %

Thu Aug 20, 2020 6:53 pm

One bit of information I forgot to include in my post is that Leaf Spy indicates that cell #68 is weak. Could one weak cell cause this problem?

GerryAZ
Gold Member
Posts: 2589
Joined: Mon Nov 22, 2010 6:47 pm
Delivery Date: 12 Jun 2011
Location: Phoenix, AZ

Re: Wildly inaccurate battery %

Thu Aug 20, 2020 7:39 pm

The Distance To Empty (DTE or GOM, aka Guess-O-Meter) has always been optimistic on my 2019 SL Plus. It tends to drop faster after the battery is partially discharged (the SOC % display also drops faster as the DTE drops). I have a couple of cells that Leaf Spy sometimes shows as weak, but am not too worried about them. If you have a failing cell that just started showing as weak, it may be causing the change you are seeing.
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 Plus purchased 8/10/2019

goldbrick
Posts: 914
Joined: Tue Aug 01, 2017 3:33 pm
Delivery Date: 01 Aug 2017
Leaf Number: 311806
Location: Boulder, CO

Re: Wildly inaccurate battery %

Fri Aug 21, 2020 11:52 am

It could help to run the car down to 0% indicated SOC and then take a reading with LeafSpy. It would be interesting to see what the low cell is reading at that point. I'd do this close to home in case the car decides to go into turtle mode at some point.

SageBrush
Posts: 5155
Joined: Sun Mar 06, 2011 2:28 am
Delivery Date: 13 Feb 2017
Location: NM

Re: Wildly inaccurate battery %

Sat Aug 22, 2020 9:48 am

WLJ wrote:
Thu Aug 20, 2020 6:53 pm
One bit of information I forgot to include in my post is that Leaf Spy indicates that cell #68 is weak. Could one weak cell cause this problem?
Yes.

There is another recent thread almost identical to yours.
2013 LEAF 'S' Model with QC & rear-view camera
Bought Jan 2017 from N. California
Two years in Colorado, now in NM
03/18: 58 Ahr, 28k miles
11/18: 56.16 Ahr, 30k miles
09/20: 54.3 Ahr; 38k miles
-----
2018 Tesla Model 3 LR, Delivered 6/2018

MikeinPA
Forum Supporter
Posts: 20
Joined: Wed Jul 08, 2015 7:20 am
Delivery Date: 21 Dec 2013
Location: SE Pennsylvania

Re: Wildly inaccurate battery %

Sun Aug 23, 2020 12:10 pm

Yes. I am fairly sure the battery % becomes correlated with the lowest cell voltage when the lowest cell is below a certain voltage . I know that sounds confusing. Above that voltage, it looks like it sets 100% by multiplying pack ahr times pack voltage, and then reduces battery % based on ahr discharged. Battery % drops slowly, GOM is dropping slowly as well--pack looks normal. Then the lowest cell crosses some voltage, and the battery% is now based on tracking the weakest cell (and likely using some calibration curve in the firmware). Battery % plummets, GOM does as well. You may notice that after really dropping quickly, it slows down again.

I could be totally wrong.
2013 Pearl White SV man 09/13 58k ser no 418089 purchased new 12/13
2013 Ocean Blue SV man 07/13 18k ser no 413361 purchased used 12/19

SageBrush
Posts: 5155
Joined: Sun Mar 06, 2011 2:28 am
Delivery Date: 13 Feb 2017
Location: NM

Re: Wildly inaccurate battery %

Sun Aug 23, 2020 8:06 pm

MikeinPA wrote:
Sun Aug 23, 2020 12:10 pm
I could be totally wrong.
Sounds right to me
2013 LEAF 'S' Model with QC & rear-view camera
Bought Jan 2017 from N. California
Two years in Colorado, now in NM
03/18: 58 Ahr, 28k miles
11/18: 56.16 Ahr, 30k miles
09/20: 54.3 Ahr; 38k miles
-----
2018 Tesla Model 3 LR, Delivered 6/2018

WLJ
Posts: 16
Joined: Fri Jun 15, 2018 1:59 pm
Delivery Date: 15 May 2019
Leaf Number: 310396
Location: Kamuela, Hawaii

Re: Wildly inaccurate battery %

Wed Aug 26, 2020 8:01 pm

Update 1. Was on my way to dealer to check weak cell when EV warning light illuminated 5 miles from dealer and car went into turtle mode. Left car at dealer where I was told battery will be pulled and faulty cell replaced or entire battery will be replaced under warranty.

WLJ
Posts: 16
Joined: Fri Jun 15, 2018 1:59 pm
Delivery Date: 15 May 2019
Leaf Number: 310396
Location: Kamuela, Hawaii

Re: Wildly inaccurate battery %

Thu Aug 27, 2020 8:59 pm

Update 2. Good news: Bad battery module will be replaced under warranty. Bad news: Module will be shipped from mainland to Hawaii by boat, which will take about 3 weeks.

cwerdna
Posts: 10989
Joined: Fri Jun 03, 2011 4:31 pm
Delivery Date: 28 Jul 2013
Location: SF Bay Area, CA

Re: Wildly inaccurate battery %

Thu Aug 27, 2020 9:14 pm

^^^
That is good news they determined what's wrong. Did they give you a loaner? That's a hell of a long wait. :(

'19 Bolt Premier
'13 Leaf SV w/premium (owned)
'13 Leaf SV w/QC + LED & premium (lease over)

Please don't PM me with Leaf questions. Just post in the topic that seems most appropriate.

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