tivollix
Posts: 65
Joined: Wed Apr 03, 2013 6:56 am
Delivery Date: 18 Mar 2013
Leaf Number: 006065

Bad cells reported by CVLI test with LeafSpy pro

Hello,
I just did a CVLI test on my battery because the dealer did one with my car but told me that everything was fine.
Many cells are shown as bad. Should I repport that to the dealer or Nissan?

Image

Capacity evolution, the spike in capacity is the P3227 update:
Image
Last edited by tivollix on Thu Oct 16, 2014 10:10 am, edited 1 time in total.
2016 Leaf since 21000KM.
2015 for 30000KM
2011 Black SL Leaf. Demo. In service: 2013/03
Sold at 38000 KM
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DaveEV
Posts: 6252
Joined: Fri Apr 23, 2010 3:51 pm
Location: San Diego

Re: CVLI test, what do you think

What do the CP voltages look like when the pack is fully charged?
tivollix
Posts: 65
Joined: Wed Apr 03, 2013 6:56 am
Delivery Date: 18 Mar 2013
Leaf Number: 006065

Re: CVLI test, what do you think

Hello,
Here is the evolution during my commute:

After 80% charge and before driving:
Image

After 6 miles of very slow driving:
Image

After 22 miles:
Image

The "weak" cells are visible very fast.
drees wrote:What do the CP voltages look like when the pack is fully charged?
2016 Leaf since 21000KM.
2015 for 30000KM
2011 Black SL Leaf. Demo. In service: 2013/03
Sold at 38000 KM
muus
Posts: 186
Joined: Mon Jun 28, 2010 9:48 am
Delivery Date: 16 Jun 2014
Location: Ottawa, ON, Canada

Re: Bad cells reported by CVLI test with LeafSpy pro

tivollix wrote:I just did a CVLI test on my battery because the dealer did one with my car but told me that everything was fine.
When you brought the car to the dealer, was your battery at a low state of charge? Maybe the dealer didn't bother draining down the battery to do the test?

How do you do a CVLI test in LeafSpy pro? Does it automatically show you the bad cells when you are at a low SOC? When I'm below VLBW I have a much wider range of voltages (about 145mV) but none are reported as being bad.
2014 Leaf SL (Gun Metal Grey)
Upgraded Panasonic EVSE (20A)
JuiceBox bought from Kickstarter
23 months 50,000 KMs
Leaf Spy Pro: 62Ahr (up from a low of 50Ahr)
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RegGuheert
Posts: 6419
Joined: Mon Mar 19, 2012 4:12 am
Delivery Date: 16 Mar 2012
Leaf Number: 5926
Location: Northern VA

Re: Bad cells reported by CVLI test with LeafSpy pro

I think your capacity plot has turned south partially due to your pack being unbalanced. If you have been charging exclusively to 80% for a long time, you really should do a 100% charge several days in a row to get the pack back into a full balance. If you do that, I think you will see a bump back up in reported capacity and no more CVLI failures.
RegGuheert
2011 Leaf SL Demo vehicle
10K mi. on 041413; 20K mi. (55.7Ah) on 080714; 30K mi. (52.0Ah) on 123015; 40K mi. (49.8Ah) on 020817; 50K mi. (47.2Ah) on 120717; 60K mi. (43.66Ah) on 091918.
Enphase Inverter Measured MTBF: M190, M215, M250, S280
tivollix
Posts: 65
Joined: Wed Apr 03, 2013 6:56 am
Delivery Date: 18 Mar 2013
Leaf Number: 006065

Re: Bad cells reported by CVLI test with LeafSpy pro

Thank you for your feedback. I dont charge the pack daily to 100% in summer in order to limit pack aging. Usually I still do it twice a month.
Now that cold days are back I will switch to 100% charging daily as soon as we will be below 32F during the nights. I will redo the test then.
RegGuheert wrote:I think your capacity plot has turned south partially due to your pack being unbalanced. If you have been charging exclusively to 80% for a long time, you really should do a 100% charge several days in a row to get the pack back into a full balance. If you do that, I think you will see a bump back up in reported capacity and no more CVLI failures.
2016 Leaf since 21000KM.
2015 for 30000KM
2011 Black SL Leaf. Demo. In service: 2013/03
Sold at 38000 KM
tivollix
Posts: 65
Joined: Wed Apr 03, 2013 6:56 am
Delivery Date: 18 Mar 2013
Leaf Number: 006065

Re: Bad cells reported by CVLI test with LeafSpy pro

The dealer did discharge the battery to one bar, the interesting part was that he did not see that the battery timer was on ( I forgot to remove it). So The car was empty when I got it back...

muus wrote:
tivollix wrote:I just did a CVLI test on my battery because the dealer did one with my car but told me that everything was fine.
When you brought the car to the dealer, was your battery at a low state of charge? Maybe the dealer didn't bother draining down the battery to do the test?

How do you do a CVLI test in LeafSpy pro? Does it automatically show you the bad cells when you are at a low SOC? When I'm below VLBW I have a much wider range of voltages (about 145mV) but none are reported as being bad.
2016 Leaf since 21000KM.
2015 for 30000KM
2011 Black SL Leaf. Demo. In service: 2013/03
Sold at 38000 KM

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