Assaf
Posts: 60
Joined: Sun Jul 21, 2013 9:46 am
Delivery Date: 26 Aug 2012
Leaf Number: 024379

Bad Module in Brand-New 2017 SV

Tue Jun 13, 2017 10:42 am

A couple of weeks ago we started our 3rd consecutive Leaf lease on a 2017 SV, our first 30 kWh model.
The next day we took it to the mountains for a spin, and were dismayed to see the %SOC drop much faster than expected. Overall range performance was a good 15%-20% below expectations for the season/driving/etc., expectations I'm very familiar with from nearly 5 years of Leaf driving.

After confirming the findings a couple more times - accelerated %SOC drop seen starting around 65-70% till around 25-30% - I contacted the sales person (a very known and liked person in Leaf circles), and right now I'm sitting at the dealership waiting for service.
They just confirmed *one* bad module out of 48, and are chatting with Nissan about whether to replace the module or the entire pack.

My main question is: how likely it is that only one bad module will be responsible for 15-20% range loss? If not very likely, I will need to push back if they try a single-module fix, and demand either a full-pack replacement or a lease swap.

Please respond quickly, but only if knowledgeable about the matter. Links to authoritative info also gratefully accepted.

Thanks!

Assaf

rmay635703
Posts: 409
Joined: Wed Jan 19, 2011 7:43 pm

Re: Bad Module in Brand-New 2017 SV

Tue Jun 13, 2017 11:48 am

One bad module does cause the behavior you state.

No one can say for certain any further than that

Assaf
Posts: 60
Joined: Sun Jul 21, 2013 9:46 am
Delivery Date: 26 Aug 2012
Leaf Number: 024379

Re: Bad Module in Brand-New 2017 SV

Tue Jun 13, 2017 12:01 pm

Thanks!
Do you have any reference for this, though?
Also, do bad-module swaps generally work, or is it only the start of long-term torture?

Nissan hasn't gotten back to me yet so I have some time to do my HW.

Assaf

DaveinOlyWA
Gold Member
Posts: 12052
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Delivery Date: 10 Nov 2016
Leaf Number: 314199
Location: Olympia, WA
Contact: Website

Re: Bad Module in Brand-New 2017 SV

Tue Jun 13, 2017 1:55 pm

One bad module is like one bad link in a chain. The cutoff voltage is based on lowest cell reading, not the average cell reading. Your module was not "very" bad cause it could have caused a much greater loss of range. I think there was someone here who reported going from 75 miles on GOM (24 kwh pack) to Turtle in a few miles.
2011 SL; 44,598 miles. 2013 S; 44,840 miles.2016 S30 (build 10/2016)"low water marks" 24,261.3 miles.363 GIDAhr 80.66Hx95.95%kwh28.1QCs205,L2's 226
My Blog; http://daveinolywa.blogspot.com" onclick="window.open(this.href);return false;

Phatcat73
Posts: 428
Joined: Fri Feb 08, 2013 2:44 pm
Leaf Number: 401511
Location: Buffalo Grove, Il

Re: Bad Module in Brand-New 2017 SV

Tue Jun 13, 2017 9:37 pm

I thought the newer packs were sealed shut vs the older packs which were bolted. Let us know what they do.
2016 SV; purchased 20-Jan-17, <5k, 98% SOH; 01-Apr-17
2013 SV; purchased 6-March-13 44k, 81% SOH; 3-Apr-17
2015 S; purchased 29-July-14, moved to AZ Nov-2014, 19k, 83% SOH; 30-Mar-17
(LD storage) 2009 Ford Escape Hybrid 4x2), 101k

Assaf
Posts: 60
Joined: Sun Jul 21, 2013 9:46 am
Delivery Date: 26 Aug 2012
Leaf Number: 024379

Re: Bad Module in Brand-New 2017 SV

Wed Jun 14, 2017 12:46 pm

The Nissan battery test at near empty yielded the following:
One "cell" (I assume module) at 3.52v, vs. the test threshold of 3.63v (I assume Fail is below threshold).

They were told by Nissan to wait for a more senior Leaf expert who perhaps works in another shop in the region(?), to come in and do more testing. The report mentions gradual discharge from 100% down to 10%. He was scheduled to come in 2 days later.

I had to pick up the car yesterday evening, though, b/c my son is scheduled to have a driving test Friday, and Leaf is what he's used to driving on, besides likely not having insurance for the loaner. It's our only car.

The report sounds much milder than their verbal description of a "bad module" or pre-test suspicions of a "shorting module". On the other hand, I still wonder how can one module with voltage ~3% below spec, cause a 15%-20% range damage.
I also wonder whether this is just a more severe case of "battery teething problems" that will resolve itself with some built-in battery management balancing over some time.

Any insight and constructive input welcome.

Thanks!

Assaf

LeftieBiker
Posts: 6932
Joined: Wed May 22, 2013 3:17 am
Delivery Date: 31 May 2013
Location: Upstate New York, US

Re: Bad Module in Brand-New 2017 SV

Wed Jun 14, 2017 12:57 pm

Think of it as the car being limited to the capacity of just that one cell. That's essentially the case, because the way the BMS works, the car has to conform to the voltage parameters of the weakest cell, not the strongest.
2013 "Brilliant Silver" SV with Premium Package and no QC, and 2009 Vectrix VX-1 with 18 Leaf cells.

The most offensive, tasteless phrase in use here is "Pulled the trigger." I no longer respond to posts that use it.

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jhm614
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Joined: Fri Apr 23, 2010 7:48 pm
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Leaf Number: 000493
Location: Arlington, TX

Re: Bad Module in Brand-New 2017 SV

Wed Jun 14, 2017 1:00 pm

Would LeafSpy help to verify that a single module is bad?
2011 Brilliant Silver SL - 105,000 gasoline free miles so far.
4BL: 06/29/13 @ 27 months, 43,520 miles, 42.56 Ahr. New 12 bar battery: 09/09/13
4BLx2:12/31/16 @ 69 months, 99,475 miles, 42.99 Ahr.

cwerdna
Gold Member
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Joined: Fri Jun 03, 2011 4:31 pm
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Location: SF Bay Area, CA

Re: Bad Module in Brand-New 2017 SV

Wed Jun 14, 2017 3:31 pm

jhm614 wrote:Would LeafSpy help to verify that a single module is bad?

Yes.

'13 blue Leaf SV w/premium package (owned)
'13 blue Leaf SV w/QC + LED & premium packages (lease over, car returned)
'06 Prius

Assaf
Posts: 60
Joined: Sun Jul 21, 2013 9:46 am
Delivery Date: 26 Aug 2012
Leaf Number: 024379

Re: Bad Module in Brand-New 2017 SV

Wed Jun 14, 2017 5:51 pm

Would you have to draw the battery down to ~5% for the LeafSpy test, or can you just do it at any charge level?

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