SageBrush
Posts: 4747
Joined: Sun Mar 06, 2011 2:28 am
Delivery Date: 13 Feb 2017
Location: NM

Re: Cell Voltage Loss Inspection test (cell-pair test), P33E6

Sun Jul 21, 2019 11:08 am

Marktm wrote:Will set up a "test", take data and get back. Fun project for a retired guy! Just hope I don't have to push my leaf for a block to get to the front of my house after I went too far with battery depletion :shock: I was definitely a newbie at that time!

Interesting concept of pushing both "pedals" - it would seem regen and accel at the same time would cancel, or is the CAN system smart enough to only use the disks brakes when accelerating?
^^
Test with the car standing still.
2013 LEAF 'S' Model with QC & rear-view camera
Bought off-lease Jan 2017 from N. California
Two years in Colorado, now in NM
03/2018: 58 Ahr, 28k miles
11/2018: 56.16 Ahr, 30k miles
-----
2018 Tesla Model 3 LR, Delivered 6/2018

User avatar
Marktm
Gold Member
Posts: 507
Joined: Thu Jan 21, 2016 10:49 am
Delivery Date: 09 Jan 2016
Leaf Number: 022737
Location: Houston, TX

Re: Cell Voltage Loss Inspection test (cell-pair test), P33E6

Sun Jul 21, 2019 12:02 pm

Got it!
2012 Leaf SL; 43,000 miles. Battery replaced November 1st, 2016.

Dala
Posts: 99
Joined: Sun Oct 28, 2018 11:24 am
Delivery Date: 01 Jan 2015
Leaf Number: 316851

Re: Cell Voltage Loss Inspection test (cell-pair test), P33E6

Mon Jul 22, 2019 1:20 am

Marktm wrote: Quite happy with my 2012 leaf, especially with the "Lizard" replacement battery. However, it does seem that there are two weak cell assemblies - # 75,76. Do you have a recommended procedure that might help rebalance - without "peeling" to the individual cells?

Any success with a replacement business? A company called Fenix Power is working on it in the US - no updates for sometime however :roll:
Only non invasive thing you can do is to keep the car in ON position as much as possible, and charge using the slowest method possible (L1, 110V 6A). That will allow for as much cell balancing as possible.

However, if the cells balance out good at the top SOC, then the situation will not improve. Bottom balancing an EV is inherently much better than top balancing, but the BMS doesn't work that way.

User avatar
Marktm
Gold Member
Posts: 507
Joined: Thu Jan 21, 2016 10:49 am
Delivery Date: 09 Jan 2016
Leaf Number: 022737
Location: Houston, TX

Re: Cell Voltage Loss Inspection test (cell-pair test), P33E6

Mon Jul 22, 2019 4:17 am

Dala wrote:
Only non invasive thing you can do is to keep the car in ON position as much as possible, and charge using the slowest method possible (L1, 110V 6A). That will allow for as much cell balancing as possible.

However, if the cells balance out good at the top SOC, then the situation will not improve. Bottom balancing an EV is inherently much better than top balancing, but the BMS doesn't work that way.
I will drive to "turtle and beyond" , leaving the Leaf sitting in the on position as much as possible, then charge using my L1 charger (or my OpenEVSE set at 6 amps) - I have the time. Generally, the weak cells #75/76 will be the lowest voltages when at 100% charge, but the differential may only be 20 mv.

Thanks for the advice
2012 Leaf SL; 43,000 miles. Battery replaced November 1st, 2016.

LeftieBiker
Moderator
Posts: 12985
Joined: Wed May 22, 2013 3:17 am
Delivery Date: 30 Apr 2018
Location: Upstate New York, US

Re: Cell Voltage Loss Inspection test (cell-pair test), P33E6

Mon Jul 22, 2019 4:20 am

This just occurred to me, and it may be nonsense. That said, charging to the EQ stage (all 3 charging lights lit) and then running the heater on Low just might keep the voltage in the EQ stage a bit longer, giving the BMS more time to bring up the weak cells. You might have to turn the heater on and off several times.
Scarlet Ember 2018 Leaf SL W/ Pro Pilot
2009 Vectrix VX-1 W/18 Leaf modules, & 3 EZIP E-bicycles.
BAFX OBDII Dongle
PLEASE don't PM me with Leaf questions. Just post in the topic that seems most appropriate.

User avatar
Marktm
Gold Member
Posts: 507
Joined: Thu Jan 21, 2016 10:49 am
Delivery Date: 09 Jan 2016
Leaf Number: 022737
Location: Houston, TX

Re: Cell Voltage Loss Inspection test (cell-pair test), P33E6

Mon Jul 22, 2019 2:32 pm

Depleted battery totally today with mix of highway, suburban, sitting with drive on. The final SOC was 2.4% with 4 GIDS. Full power was 80,000 watts right up until turtle. When turtle kicked in, the max was around 7000 watts (LeafSpy battery bar readings). At present L1 charging (for the next 12 hours of so!).

The battery values at shutdown:
Turtle mode capture 7.22.19.jpg
Quite a surprise that the weakest cells are quite different this time - almost a year later than the last "depletion" and that the message is "all cells OK". The only DTCs are the A/C system - it's so hot, it seems 82785 and 6 are thrown regularly.
You do not have the required permissions to view the files attached to this post.
2012 Leaf SL; 43,000 miles. Battery replaced November 1st, 2016.

SageBrush
Posts: 4747
Joined: Sun Mar 06, 2011 2:28 am
Delivery Date: 13 Feb 2017
Location: NM

Re: Cell Voltage Loss Inspection test (cell-pair test), P33E6

Mon Jul 22, 2019 3:47 pm

Interesting and good data.
Looks like 3.1 volts -> Turtle

To elicit turtle at a higher SoC due to weak cells you have to stress them, meaning sustained maximum load.
2013 LEAF 'S' Model with QC & rear-view camera
Bought off-lease Jan 2017 from N. California
Two years in Colorado, now in NM
03/2018: 58 Ahr, 28k miles
11/2018: 56.16 Ahr, 30k miles
-----
2018 Tesla Model 3 LR, Delivered 6/2018

User avatar
Marktm
Gold Member
Posts: 507
Joined: Thu Jan 21, 2016 10:49 am
Delivery Date: 09 Jan 2016
Leaf Number: 022737
Location: Houston, TX

Re: Cell Voltage Loss Inspection test (cell-pair test), P33E6

Mon Jul 22, 2019 6:06 pm

SageBrush wrote: To elicit turtle at a higher SoC due to weak cells you have to stress them, meaning sustained maximum load.
I actually did the hard accelerations almost until turtle - but of course had to "tool around" close to home right before and during turtle.
2012 Leaf SL; 43,000 miles. Battery replaced November 1st, 2016.

User avatar
Marktm
Gold Member
Posts: 507
Joined: Thu Jan 21, 2016 10:49 am
Delivery Date: 09 Jan 2016
Leaf Number: 022737
Location: Houston, TX

Re: Cell Voltage Loss Inspection test (cell-pair test), P33E6

Mon Jul 22, 2019 6:08 pm

Battery temps went above 100 oF - the highest I've ever seen.
2012 Leaf SL; 43,000 miles. Battery replaced November 1st, 2016.

SageBrush
Posts: 4747
Joined: Sun Mar 06, 2011 2:28 am
Delivery Date: 13 Feb 2017
Location: NM

Re: Cell Voltage Loss Inspection test (cell-pair test), P33E6

Mon Jul 22, 2019 6:14 pm

Marktm wrote:
SageBrush wrote: To elicit turtle at a higher SoC due to weak cells you have to stress them, meaning sustained maximum load.
I actually did the hard accelerations almost until turtle
Then the weak cells passed the test ... for now

The good news for you is that when those weak cells eventually hobble the pack power, it will be a pack defect warranty rather than a degradation issue
2013 LEAF 'S' Model with QC & rear-view camera
Bought off-lease Jan 2017 from N. California
Two years in Colorado, now in NM
03/2018: 58 Ahr, 28k miles
11/2018: 56.16 Ahr, 30k miles
-----
2018 Tesla Model 3 LR, Delivered 6/2018

Return to “Problems / Troubleshooting”